Posted by Hemos on Monday October 11, @03:51PM EDT from the defusing-the-errors dept. ajs sent us a good investigative piece from the Boston Globe. Many of you recall the article about the Long Island particle accelerator that was going to try to replicate Big Bang conditions. Over the last three months, it's moved around the media, culminating with Fred Moody's scare piece about it, although the British Sunday Times recently picked it up yet again. The Globe article does a great job dissecting the actual facts behind the experiment and pokes fun at the growth of this Chicken Little-type story.
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So...what I get from this, is that Slashdot as a community isn't really any more (or less) prone to knee-jerk reactions when someone trys to stir things up.
No, they're merely as uneducated as everybody else in quantum theory. Anyway, it does seem alittle strange that people keep thinking that a bunch of physicists are going to blow up the world. I'd trust a physicist over a politician claiming the 'end of the world' any day. Besides, it's the politician that's going to cause WWIII, not the physicist. . .
-- What goes up, must come down. Ask any system administrator.
Anyone who has a more than passing interest in this story and is a fan of science fiction owes it to [him|her]self to check out Forever Peace, by Joe Haldeman. For those of you who read Forever War, the author says that it's a continuation, of sorts, of the issues he raised in the first book, though not a sequel in the strict sense.
One of the two central plot devices (you'll excuse the pun) in the book is the construction of a particle accelerator near Jupiter capable of recreating the Big Bang.
It bears a passing resemblance to David Brin's Earth. Although even that had the notion that a singularity would have to be of a certain size before it started to be a problem.
Earth was a singularly horrible book... David Brin has done pretty good stuff and less good stuff, but Earth was the literary equivalent of sticking your arm down your throat and pinching your own pancreas, hard.
--
"Have fun, be nice, veer left and never stop thinking, that's what it boils down to."
Iain Banks, Walking on Glass
warning label (Score:2, Funny) by Anonymous Coward on Monday October 11, @04:12PM EDT (#12)
"Warning: Use of this produce can cause space time to eat itself"
In my day, we didn't have particle accelerators. We had to tickle the dragon's tail with lumps of radioactive uranium isotpes. AND WE LIKED IT! These confounded kids today with their theory of evolution, beowulf clusters, open-source operating systems. MAMBY PAMBY! HUH! In my day, Mr. Watson told us there was a world market for four or five computers and we liked it.
Well, I don't think that the world is gonna end thanks to that darn Scooby Doo and those darn meddlin' kids. Romanes eunt domus? People called Romanes, they go the 'ouse? It says Romans go home. No it doesn't. What's Latin for Romans?... Now write this 100 times
Good journalism (Score:2, Insightful) by Muggins the Mad on Monday October 11, @04:15PM EDT (#15) (User Info)
It's nice to see a sensible article responding to all too common poorly researched media rubbish.
The sad thing is that it seems people would rather buy sensationalist fiction than (IMHO interesting) facts. Papers only report what their buyers want to hear.
I think experimental physics is interesting enough without wildly claiming we're going to risk the universe every few months. (I expect we'll *really* get onto that kind of dangerous stuff in a decade or two)
I would *much* rather hear that the world isn't going to end anytime soon than to hear about some physicists mucking about with something that could blow up the Earth.
OTOH, the millennium is coming soon, and I find myself suffixing prophetic sentences with "if Jesus doesn't gate-crash the party, that is." I mean, after all, due to tunneling, Jesus could show up at my New Years bash, and boy would he be ticked.
Jesus and tunneling aside, this whole thing makes me a little nervous. Scientists are the people who have high-energy atom-whackers at their fingertips. What happens if one of them decides "Hell, there's only a %0.00000000002 chance of this blowing up in my face?" Kerzap, there goes humanity.
Not a calming thought. Not a rational thought, for that matter, but still... due to tunneling there's a non-zero chance of a physicist... -- I can't think of anything witty to put here. Sorry.
Who cares about the big bang? What I want to know is what happens when they smash clueons and bogons together? What do you get - the element MadScientistium?
-- What goes up, must come down. Ask any system administrator.
I remember reading that there was a ridiculously teeny tiny insignificant chance that something horrible would occur, but no one could prove with absolute certainty for certain that it wouldn't occur. But by the same token, you be absolutely certain that the world wasn't created in 1976 and that all of history and all of people's memories were falsified to test our faith in Storkilious, True Lord of the Universe (TM).
There comes a point where "certainty" is just a topic of academic debate for metaphysicians and logicians.
However, consider what would happen if you really could create a black hole. The Army would immediately take it, hide it away and use it as a new weapon of mass destruction. Assuming, of course, there was a way to target and limit it's power, you could just drop a black-hole bomb on China or something.
Is something like this theoretically possible?
Take care,
Steve ------ Remove the text "SPAM-ME-NOT." from my e-mail address if you would like to send e-mail.
Yes, it is. You need to generate a VERY high energy density, though - it's something like the total energy output from a hydrogen bomb in three cubic centimeters. You'd probably get something just as destructive, for any military purposes, by using the hydrogen bomb.
A -much- more devastating weapon would be created if there was an effective way to tunnel, in a controlled manner. Link two quantum-scale wormholes together, get one into the target area and inflate the tunnel. Whatever you lobbed through the tunnel would arrive at the other mouth of the wormhole, without apparently traversing any intermediate space. It would be impossible to shield against, and impossible to detect.
There's that "assuming there's a way." I wouldn't put it past the army to try something like that. "We're going to generate a black hole of Chna, and so waht if it does swallow the entire solar system, it's in the name of democracy..." === -Ravagin "The Omnians say, 'Don't play God. He always wins.'"
a black hole weapon really would be devastating. So devastating, in fact, its use would be suicide.
There is a book, Forge of God by John Barnes (a good read), where a couple of mini-black-holes are dropped onto the earth's surface by malicious aliens.
The two black holes start eating through the earth, spriraling in towards the Earth's center, growing all the while. There, they meet and merge, liberating enough energy to blow the earth to hell.
Especially if you read the sequel to the Forge of God, the Anvil of Stars, in which the guys who used the black holes on us get what they deserve.
BTW, i HIGHLY recommend to anyone that they read the series, it's a great relief to read about a universe in which we are not the center, we are not the victors, but there are many species, of which some are hostile and some are not.
infinitely better than most of his other work (IMHO). Forge of god got me into bear, and unfortunately I haven't gotten as excited by anything else he's done...
However, consider what would happen if you really could create a black hole. The Army would immediately take it, hide it away and use it as a new weapon of mass destruction.
You can destroy mass? I'd love to know how... -- I support anonymous posting.
...The Army would immediately take it, hide it away and use it as a new weapon of mass destruction. Assuming, of course, there was a way to target and limit it's power, you could just drop a black-hole bomb on China or something.
One might not even need a way to target or limit its power. The point of a doomsday weapon is not to detonate it, but to get the other guy to give you what you want out of fear that you will detonate it. In all honesty, you don't even need to have the weapon, you just have to convince the other guy that you not only have it but are willing to use it. Even if it kills you.
It's the logic of people who hold up convenience stores with unloaded guns, and of people who strap explosives (or things that look like explosives) to themselves in order to get something they want.
In the anime series stated, towards the end, humanity comes to the conclusion that to defeat the enemy insect race, they must destroy another galaxy. Jupiter is converted into the Black Hole Bomb(which requires a hyperdrive engine to set it off), and used to destroy the enemy galaxy. Yes, there's a whole backstory, plot, and angst behind the show--go watch it.
Making the black hole is trivial. For a big one - collect enough mass until it collapse. You'll need mass comparable to a really big star. Expensive.
For a smaller one, compress a smaller mass, such as a mountain or the moon. Maybe you can do it by detonating lots of H-bombs around the thing.
Store the black hole in space, in a very wide orbit. When you want to use it as a weapon, change its orbit so it goes very near earths surface (or through the upper layer) of whatever nation you want to hit. Use sufficient speed so it goes back into space where you collect it for future use. An appropriately sized black hole could do a lot of damage this way, without destroying earth compeltely. Be prepared for quakes though...
Of course an asteroid strike is a lot easier and does the same damage. Conventional stuff like smuggling H-bombs into all their cities is simpler still, it is even doable.
I'd be interested in knowing if the authors of that piece have any connection to the Long Island facility or stand to gain any direct benefit from supporting the story that there is no realistic risk.
Personally, I agree with them, in my limited knowledge of particle physics, especially about the idea that collisions of this type and energy (and MUCH higher energy) happen frequently in nature, but I would feel much more comfortable if this was from a truly independant source.
The nagging question is: What if it DOES happen rarely in the uncontrolled collisions of cosmic rays in nature. How would we ever know that a world had been destroyed by conversion to strange matter or converted into a black hole? Sure there is a lot of catastrophic, random badness that happens in the universe, but is such an accident any MORE likely to happen in a controlled environment?
There is just something far to elegant about the idea that this type of experiment is just the reason there are no signs of intelligent life in the universe...
I have met both John Swain and Steve Reucroft, and they are both very intelligent and talented physicists. They have basic homepages at Northeastern (be gentle on the server, it's a rather ancient Alpha):
Whats the energy? (Score:0) by Anonymous Coward on Monday October 11, @06:49PM EDT (#129)
C'mon guys. Can somebody just tell how many GeV's they are going to achieve with this accelerator or post a more informative (and scientific) reference to that stuff? Concerning the fears, we are currently much, MUCH below the necessary energies. We are to go some other 50 orders of magnitude (thats 10^50 times higher energies).
RHIC will operate at energies of up to about 100 GeV per nucleon (that is, proton or neutron).
There is lots of scientific information about RHIC here. Follow the links to "Documentation" and "RHIC Design Manual" for detailed information about its motivation and specifications.
I'm pretty sure more informative documents can be found at www.rhic.bnl.gov, or check the last few Quark Matter proceedings (Nucl Phys A 610, 638, ...)
As mentioned in the previous Slashdot discussion, the March 1999 "Scientific American" mentioned this, and a letter to the editor reply mentioned that reactions with higher energy happen in Earth's own atmosphere. After many millions of years of such activity, we haven't been destroyed yet. We can also see that it hasn't happened to eight other planets, moons, and the Sun.
Holy! (Score:1, Funny) by Anonymous Coward on Monday October 11, @04:18PM EDT (#19)
Re:Holy! (Score:1) by spiral on Monday October 11, @04:26PM EDT (#26) (User Info)
>I wonder what a beowulf of black holes would do?
Don't even bother thinking about it. It would *really* suck.
(sorry...I couldn't resist)
Re:Holy! (Score:1) by Phase Shifter on Monday October 11, @06:17PM EDT (#115) (User Info)
>>I wonder what a beowulf of black holes would do?
>Don't even bother thinking about it. It would *really* suck.
Yeah, but think of the spin states. Couple them together and you could have a beowulf quantum cluster. At least, as long as Microsoft doesn't require us to license the Grand Unified Theory.
Re:Holy! (Score:0) by Anonymous Coward on Monday October 11, @04:30PM EDT (#31)
I'm always for experiments, but when something could produce a black hole, shouldn't we be REALLY sure that it can't first? Actually, I've read that black holes under a certain size evaporate. Steven Hawking too I believe. Another note, if creating the conditions of the beginning of the universe creates black holes, shouldn't the universe be littered with the things by now? We've just recently (couple of years) found a black hole.
Black holes (Score:2) by Tau Zero(spherethis@youknownottoincludethis.yahoo.com) on Monday October 11, @05:46PM EDT (#85) (User Info)
... when something could produce a black hole, shouldn't we be REALLY sure that it can't first?
The Schwarzchild radius of a black hole is given by the equation Rs = 2GM/c^2. Now G is a mighty small number, the mass M of 2 gold atoms is less than 1e-22 kilograms, and 1/c^2 is a pretty small number too (about 1e-17 in MKS units). The upshot is that a black hole with the mass of 2 gold atoms would be much, much smaller than a proton. The atoms are too wide to get all of the mass into a space that small during a collision.
Actually, I've read that black holes under a certain size evaporate. Steven Hawking too I believe.
Yup. You'd get a pretty good energy flash from the decay, and then it would be gone.
Another note, if creating the conditions of the beginning of the universe creates black holes, shouldn't the universe be littered with the things by now? We've just recently (couple of years) found a black hole.
Astrophysicists have been finding evidence of things that couldn't be much else for years (things in galactic cores, whose influence on surrounding objects shows they have masses of a million suns and more), but given that a black hole doesn't radiate or do anything in and of itself other than pull on things it's difficult to prove that the object is truly a black hole and not something else. Every galaxy seems to have a big one in the center.
What was theorized that we might see left over from the Big Bang is quantum black holes, of a few million or billion tons (the mass of a big iceberg or small asteroid). So far there is no evidence for their existence. -- Deja Moo: The feeling that you've heard this bull before.
but given that a black hole doesn't radiate Actually, the THINGS you are talking about are quasars, pulsars, and their derivatives, and were detected by the massive amounts of x-ray raditation that they emit. These bursts are the most powerful forms of radation known (although they arent really being radiated by teh balck hole, and are thought to be produced by molecules hitting each other really really fast, somewhere near about half the speed of light). And of course you simply made an error when you stated that black gholes dont really radiate, right (since you had just said that they do?)
For links referring to a discussion on Hawking raditaion as well as the original paper which described it, see my first post. The truth is out there - we'll let it back in after it sobers up a bit. -The Cube
Actually, I've read that black holes under a certain size evaporate. Steven Hawking too I believe.
I don't think there is any support for that theory. To my knowledge, Stephen Hawking has not evaporated yet. Can anyone confirm?
Hmm, that's odd... (Score:0) by Anonymous Coward on Monday October 11, @04:22PM EDT (#22)
Perhaps the most astonishing feature of physics is the way that it ties together seemingly disparate phenomena at widely different scales. The same laws govern the big and the small and everything in between, and looking at one scale, we can learn something about another.
I thought that the General Theory of Relativity and Quantum Mechanics weren't unified as of yet. This author seems to want to calm our worries, but making statements that are outright errata doesn't help his credibility, or my feelings of security that anyone other than the experimenters themselves really knows what they're doing.
They aren't, so his statement is technically false.
However, I think it's pretty commonly believed that a grand unified theory (not to be confused with any specific Grand Unified Theory) of some sort does govern the entire universe. Whether it be a single equation, or a set of equations, the universe acts according to that grand theory.
So while his statement is technically incorrect using today's theories, eventually (for suitably arbitrary definitions of "eventually") we will figure out how to unite all of the various theories and forces into one encompassing mathematical/physical explanation.
Personally, I almost wish a black hole would sweep down from that big bad particle accelerator and wipe out earth, just so we could stop having to read these ignorant doomsayers (Fred Moody) predict the end of the world....how's that for recursive irony? :)
"Get out of my way! Can't you see I'm trying to save the world!!" -Xion
But you can be certain of one thing -- there will be a TV movie made within six months about a black hole created by clueless scientists that threatens to destroys the earth. Destroy, that is, until the hero scientist that no-one listened to comes up with a magic black hole plug...
Only, I doubt that they'll even get the term "Black Hole" right. My bet is on, "Blank Hole" or perhaps "Black Hood" or somesuch. Educational sig-line: Choose rhymes with lose. Chose rhymes with goes. Loose rhymes with goose.
The idea that we are going to destroy the world with the RHIC is absolutely ridiculous. I remember reading that a large number of physicists thought the first nuclear weapon would ignite the atmosphere, destroying all life on Earth. Didn't happen. Now we have a _journalist_ - not even a Ph.D. in physics - claiming that we're going to create a black hole with the RHIC. This is a remote possibility, to say the least - collisions at much higher energy than this happen in our upper atmosphere daily without destroying us. But assuming for a moment that a black hole is created, what happens? The answer is simple: it will evaporate. Black holes lose mass constantly (a consequence of quantum mechanics). A black hole of the size that would be created by two gold ions colliding would be gone in a matter of microseconds, if I remember my astro course correctly. What's more, the Swarzschild radius would be so tiny, and the densities in the ion beam so low, that there is only a probability on the order of 1E-35 that another ion would fall past the event horizon before said event horizon disappears. In short, we have nothing to worry about. At least not from RHIC. I'd be more worried about ballistic nukes from China. LinuxPPC - it's Linux for your Mac! www.linuxppc.org
I remember reading that a large number of physicists thought the first nuclear weapon would ignite the atmosphere, destroying all life on Earth. Didn't happen.
You're not giving the Manhattan Project gang enough credit. As I heard the story, they feared that setting off an atomic bomb might destroy the world only until they had explored the physics enough to prove that it wouldn't. Nobody was holding his breath when the first a-bomb was tested, at least not for that reason.
I'm sure the same thing has happened in the current situation. Unfortunately, the RHIC folks don't have the luxury of a super-duper-secret classification to protect them from the scientifically illiterate press.
You're right, nobody was really holding their breath when that first bomb was tested (or rather they were, but not because they were afraid of destroying the planet (at least not right then)). On the other hand, the first tests on Bikini atoll, which got a substantial amount of publicity, had a lot of people holding their breath. Not informed people, to be sure, but people nonetheless. A rumor got started that a new sort of superbomb was being tested which would activate a runaway chain-reaction that would destroy the planet. As you said, didn't happen. The resulting mood of impending doom, however, was credited with lowering inhibitions and leading to the sucess of the Bikini swimsuit, which came out around that time and was named after the atoll.
"Never let your sense of morals prevent you from doing what is right" -Salvor Hardin
Re:Rubbish! (Score:0) by Anonymous Coward on Monday October 11, @05:56PM EDT (#95)
Never mind but it was not just a journalist only and they considered the whole thing. Regarding black holes and stuff, it is all much theory. No-one really knows. It is always easy to laugh or react with arrogance, but science has to consider even remote risks.
The thing is that often people laughed with dire results later. Thinking it through is the right way to go and the right way to come nearer to what is the truth and they did it right.
mister attack says: The idea that we are going to destroy the world with the RHIC is absolutely ridiculous. I remember reading that a large number of physicists thought the first nuclear weapon would ignite the atmosphere, destroying all life on Earth. Didn't happen.
This is a logical fallacy known as post hoc ergo propter hoc. Just because we haven't destroyed the earth in the past doesn't mean we can't do it.
Now we have a _journalist_ - not even a Ph.D. in physics - claiming that we're going to create a black hole with the RHIC.
Ad hominem. In fact, objections have been raised within the scientific community. They have been taken seriously enough to be reviewed by the laboratory. They disagreed, of course.
This is a remote possibility, to say the least - collisions at much higher energy than this happen in our upper atmosphere daily without destroying us. But assuming for a moment that a black hole is created, what happens? The answer is simple: it will evaporate.
At last a real argument. I happen to agree with you in principle; I'm not going to lose sleep over these experiments. But I don't think that going around shouting "rubbish!" at people is the way to make your point. There are valid scientific questions to be raised here, and while the field of high-energy physics may be dominated by people who believe it's perfectly safe, the objections do not come from left field. It may not be this experiment, but I would not rule out the possibility that in the near future we could devise experiments that would be capable of creating (say) a microscopic black hole.
I'd be more worried about ballistic nukes from China.
Most people should worry about a) heart disease, b) lung cancer, and c) an auto accident, in roughly that order. Since we all know that very few people give those very real dangers any thought at all ....
No, I don't believe RHIC is going to kill us all. But can we indeed come up with an experimental device that could? Most certainly. And human history is filled with enough follies by people who "know what they're doing" (say, Challenger) that I don't put all my trust in the intelligentsia here. The only safeguard is an atmosphere of collegiality where objections such as the one raised against RHIC are treated seriously and given due consideration in a peer review process.
That has happened, and has completed. It's only afterwards that the media really got hold of the story, and as they always do, they report it as if it were two equally valid political positions. Don't give in to the hysteria by treating all such objections with contempt. ---- Lake Effect, a weblog A palimpsest of the eloquently ironical and eclectic.
Ok, so you took an intro logic course too. Good for you. I assumed that most of the readers would have been charitable enough to assume that I knew that me prefacing statements were just that - prefacing statements. NOT, repeat NOT part of the actual argument.
Okay, now that I'm done with the prefacing statements:), I'll deal with your objections.
the objections do not come from left field
Actually, in this case they do. There is only a very small probability that a Very Bad Thing will happen. And in this case, as in every quantum mechanical case, a very small probability is like the probability that a football-sized chunk of the Sun suddenly could appear on one's desk. Yes, it could happen, but don't hold your breath.
And human history is filled with enough follies by people who "know what they're doing"
Oh my, do we have a logical fallacy here? Why yes, boys and girls. It's our old friend, the argumentum ad hominem. Just because authority figures screwed up in the past (and in Challenger's case, it was bureaucrats who pushed the launch; the engineers, I believe, knew it probably wasn't safe to launch the shuttle), doesn't mean we can discount what they say now. We're also bordering on a conceptual slippery slope here. Just so you know.
Fianlly, your whole opening could be construed as the start of a strawman attack on my argument. By giving unimportant parts of my posting with which you find fault such prominence, you aare implicitly trying to discredit the rest of my post. Let's stick to the facts from now on, shall we? Yes, and avoid further rhetoric? Thanks so much. LinuxPPC - it's Linux for your Mac! www.linuxppc.org
And human history is filled with enough follies by people who "know what they're doing"
Oh my, do we have a logical fallacy here? Why yes, boys and girls. It's our old friend, the argumentum ad hominem. Just because authority figures screwed up in the past (and in Challenger's case, it was bureaucrats who pushed the launch; the engineers, I believe, knew it probably wasn't safe to launch the shuttle), doesn't mean we can discount what they say now.
Mister Attack,
I think it's time to review your notes. This is not an ad hominem. The point is that experts are not infallible. Nowhere is it claimed that the experts are always wrong or that their opinions (in their respective fields, of course) are not more valid than those of others (i.e. not experts). All that is claimed is that the experts sometime make mistakes. In the case of the anhililation, even the smallest possibility of a mistake is too great. That was the point, and it is valid.
In other words, it is a proof by counterexample. I'll let you figure out the details.
i apologize. apparently i need to have another look at the ol' Logic Book. I'm getting a little rusty, it seems. My deepest apologies to anyone I may have offneded. In any case, the counterexamoke which was offered was invalid, because Challenger flew on account of bureaucrats ignring their engineers. The moral of the story is: listen to the scientists, ESPECIALLY if they say something's not safe. Whether a probability on the order of 1E-35 is too great a risk, well, that's a question for somebody else. LinuxPPC - it's Linux for your Mac! www.linuxppc.org
In any case, the counterexamoke which was offered was invalid, because Challenger flew on account of bureaucrats ignring their engineers. The moral of the story is: listen to the scientists, ESPECIALLY if they say something's not safe.
Which could be construed as undermining your original argument. Still, when faced with scientist X saying it's safe, and scientist Y saying it isn't, you don't always have the grace of an easy decision. Not all the "engineers" were objecting to the launch. And the attitude at NASA was very much post hoc ergo propter hoc.
The point I'm trying to make is roughly: any bureaucrat/politician/careerist scientist may choose to demonstrate a 1 in 1^n probability of risk. But are they correct, or are they cooking the numbers? Do we assume that we know enough to calculate these things with necessary precision? Before Trinity (to return to your original example) there had been not a single nuclear explosion in all of human history. With no experimental data, how could the Manhattan Project experts who calculated the risk of "igniting the atmosphere" really be certain? They couldn't. They could make educated guesses, and they did, and fortunately they were right.
My deeper point here is that we are at a point in human capability where we can make things -- quark guns, atom bombs -- that have potentially devastating side-effects. Therefore, a minor amount of prudence and forethought seems like a small price to pay for peace of mind. ---- Lake Effect, a weblog A palimpsest of the eloquently ironical and eclectic.
But are they correct, or are they cooking the numbers?
If you want to do the calculations yourself, go ahead - you should be able to find the necessary information in any good modern physics textbook. The point here is that the scientific community is based largely on trust - trust that people do not cook their numbers, part of a larger trust in something called scientific integrity. But, there are safeguards - experiments and calculations are designed to be repeatable. If you don't trust someone else's numbers, you can check them yourself. If you don't believe someone's experiments, you can follow the same steps they did and (hopefully) get the same results.
My deeper point here is that we are at a point in human capability where we can make things -- quark guns, atom bombs -- that have potentially devastating side-effects. Therefore, a minor amount of prudence and forethought seems like a small price to pay for peace of mind.
Nobody is advocating going through with experiments without at least "a minor amount of prudence and forethought." The reason I think these experiments are safe is that we have gone through the forethought and concluded that there is no significant risk of disastrous consequences. Now we have a newspaper article stating that some people disagree. The arguments that I have seen which imply that this is an unsafe experiment to do are simply not convincing - either there is a flaw in the reasoning, or there is a flaw in the fundamental understanding of what will be happening at RHIC. Of course, I am keeping an open mind to new abjections; I simply hold that no objection which has been raised thus far is strong enough to warrant taking away this potentially very useful scientific tool.
P.S. What, exactly, is a "quark gun"? AFAIK, our current understanding is that the Standard Model precludes free quarks. And why should I be worried about them, assuming they exist? What devastating consequences could they bring?
LinuxPPC - it's Linux for your Mac! www.linuxppc.org
Uh, after this post, I'll let others judge which of us is resorting to more rhetoric. ---- Lake Effect, a weblog A palimpsest of the eloquently ironical and eclectic.
Most people should worry about a) heart disease, b) lung cancer, and c) an auto accident, in roughly that order. Since we all know that very few people give those very real dangers any thought at all ....
Actually, a lot of people do take these seriously. I, for example, do not drive a car in order to decrease everyone elses chance of (c), as I am a terrible driver.
The point in being concerned about small chances of global catastrophy is not that it's likely, it's that right now we have all of our eggs in one basket and we can't very well afford to go throwing rocks....
I don't think this one accelerator is a big deal, but the thought is important. Every day, we receive several gamma-ray emmisions from deep-space. Many of them do not seem to be associated with any detectable stellar phenomenon. What if these gamma-ray sources are what's left of some world where a researcher said "I don't *think* this will cause a kilogram of matter to totally convert"? I haven't done the math, so I don't know how much matter would have to convert before you saw the kind of gamma-ray emmisions that we detect, but I suspect it's much less than an earth-size planet....
These are important things to think about. Even if we decide that it's more important to discover the nature of the universe than to avoid a little risk, we should consider what risk it is that we're not avoiding.
-- Aaron Sherman (ajs@ajs.com) Perl Guy and Executive Glue Sniffer
mister attack says: >> The idea that we are going to destroy the world with the RHIC is absolutely ridiculous. I remember reading that a large number of physicists thought the first nuclear weapon would ignite the atmosphere, destroying all life on Earth. Didn't happen. This is a logical fallacy known as post hoc ergo propter hoc. Just because we haven't destroyed the earth in the past doesn't mean we can't do it.
Actually this is a non post hoc ergo non propter hoc which is something logically different. ;-p
Ivo
We are all in the gutter, but some of us are looking at the stars
Most people should worry about a) heart disease, b) lung cancer, and c) an auto accident, in roughly that order.
People worry less, because this won't destroy a nation, humanity or the earth. Unless everybody get a heart attack at the same time, and that probability is low. It is still bigger than the probability that an accelerator should destroy the universe though.
Ever notice that our science consists mostly of bashing things together or sticking things in other things. We've been doing this for tens of thousands of years now. Maybe it's time to start hunting for a new paradigm.
Hm. Taking things apart/Putting them together. Synthesis/Analysis.
What tools would you suggest we use instead? These categories seem kind of general. -- I wonder if junk bots search for bolded REMOVE THIS or NO SPAM in addresses? (Obfuscated address a result of increased spam since open use on slashdot)
It just occurred to me some nitpicker might infer I confused synthesis/analysis, rather then having put them in the wrong order (for that comparison).
I hadn't.
-- I wonder if junk bots search for bolded REMOVE THIS or NO SPAM in addresses? (Obfuscated address a result of increased spam since open use on slashdot)
Gregory Benford's Cosm is an interesting look at this concept: A UCSD physicist goes to Brookhaven and slams a few uranium nuclei together using the RHIC, and creates a big bang. Since Benford is a physicist himself, he surely got the idea from early discussions of the possibilities in egghead literature.
In Benford's vision, the universe created was seperate from ours, joined only by a "window" that exhibited itself as a mysterious black sphere about the size of a bowling ball, but massive. Most of the novel deals with the scientists solving the mystery of "what the hell is this thing?" Fun, hard, witty SF, with lots of scenes taking place in La Jolla, Pasadena, and Brookhaven.
Overall, very similar to Timescape, also by Benford. Also set at UCSD. Also about scientists. Also a great read.
After Artifact, Gregory Benford will have to come around, buy me dinner and slip me a few $50 bills before I read another of his books... The guy couldn't do believable characters if they leapt out of the WP and bit his scrotum...
--
"Have fun, be nice, veer left and never stop thinking, that's what it boils down to."
a committee of prominent physicists has also written a report, titled "Committee Report on Speculative "Disaster Scenarios" at RHIC". you can find it at http://www.bnl.gov/bnlweb/rhicreport.html . you will find the three 'disaster' scenarios described there.
OK, lets say nothing black-hole-ish happens. Then the scientists would know a little more about the big-bang. What if a black-hole does form? Ooohhh Myyyy Goooood!!!!!!!!! Then fwoop it doesn't matter anymore does it. Why? Well, everyone on earth would almost instantly be compressed into an infinitly small space. We're all dead and then nothing would matter anymore anyways....
>>Fred Moody is the author of I Sing the >> Body Electronic: A Year with Microsoft on >> the Multimedia Frontier and of The >> Visionary Position: The Inside Story of the >> Digital Dreamers Who Made Virtual >> Reality a Reality. His column appears on >> alternate Wednesdays.
A ha! so he spent a year with Microsoft, it goes without saying that we can't trust/listen to him
Actually... (Score:0, Troll) by Anonymous Coward on Monday October 11, @04:45PM EDT (#41)
In a parallel universe (I think it was the one where Microsoft products work) RHIC did create a blackhole which consumed the local galaxy.
They mention "strange matter" a few times, with no explanation. I am but an engineer, and not very knowledgable about such things. But surely there is a theoretical physicist in the audience who could field this question, and enlighten the Slashdot readership. Please?
thanks, --Lenny "A good machine dreams of the day it will be replaced by a better machine." --Douglas Coupland
There is a good explanation from Prof. Jaffe at MIT. (Scroll down a few pages to get to the relevant part of the transcript. The realvideo at the top picks up around at the interesting bit, and has more info.)
According to current theory, quarks come in six flavors: top and bottom (sometimes called truth and beauty), strange and charmed, up and down.
Ondinary particles in the atomic nucleus (neutrons and protons) consist only of up quarks and down quarks. The other types of quarks may be produced in high-energy collisions, however.
IIRC, Strange matter is composed of these other types of quarks. In general, these particles are unstable and sooner or later (usually MUCH sooner) turn into normal quarks, giving off radiation in the process. Some people still worry about some chain reaction where strange matter converts normal matter into more strange matter, but I find this highly unlikely.
Earth is constantly bombarded by muons (related to electrons like strange quarks are to up quarks) and hasn't imploded on itself yet, even after billions of years. I really doubt we'll succeed in the 0.00000000000000000000003 seconds the collisions in the accelerator will last.
Recalling that normal matter is made up of atomic particles, which themselves are composed of subparticles (quarks and leptons). Quarks summarized here. "Strange matter" is simply matter that is made up mainly of the quark with the flavor "strange" (the name comes from the strangeness of their long lifetimes compared with other known particles).
It holds a relationship to normal matter something akin to antimatter's, although it is not antimatter (there is "normal" strange matter and "antimatter" strange matter). Basically, it looks like normal matter but isn't made up of the same kinds of subparticles. I think that strange matter in general is nowhere near as stable as normal matter. ---- Lake Effect, a weblog A palimpsest of the eloquently ironical and eclectic.
The Standard model of particle physics contains two types of particles bosons and fermions. To a first approximation fermions can be thought of as 'stuff' and the bosons carry the fundemental forces between various bits of 'stuff'. (For example an electron is a fermion that feels electromagnetic forces when it interacts with a photon). The fundemental forces of interest here are the weak and strong forces.
The fermions that feel the strong force are called the quarks and are individually named up, down, *strange* (so called because it wasn't expected at the time it was discovered), charm, bottom and top. The gluons (bosons for the strong force) interact very strongly with both the quarks and each other to such a degree that the quarks are actually bound together (nobody has ever experimentally observed a free quark) into groups of either three or two quarks, like the proton (two ups and a down) and the neutron (two downs and an up).
Strange matter is a grouping a quarks that include the strange quark. The reason why you haven't heard about strange matter before (but have heard about neutrons and protons I hope :) is that the strange quark can decay via the weak force into the up and down quarks (mainly the up) and will do so because it's heavier and therefore it's bound states are heavier and things will always decay to a state with lower energy if they have the chance (remember E=mc^2 so heavier things have more energy).
The idea behind Stranglets is that the strange quark may actually form bound states that are energetically favourable, but that these states take a lot of energy to form (actually ripping the current bound states appart and re-arranging them is hard, but once you do it the state has lower energy). So RHIC might have a high enough energy to form them at which point they would start converting evreything they touch into stranglet including big particle accelerators, planets etc..
This idea just seems to be plain wrong. The calculation that the idea is based on is dubious, and as mentioned previously, if such energetically favourable states *could* be formed it's hard to see why they haven't already be formed as cosmic rays interact with the upper atmosphere.
So, there you go, I'm almost 99% certain that RHIC won't destroy the planet. What more could you ask for?
I must gain objective knowledge of the origin of all space, time, matter and energy, including me, the knower himself, and no rinky-dink little backwater planet overpopulated with superstitious primitives is going to stop me! Igor, the switch!
Interestingly depressing theory that Sagan had tho, that we can't find any ETI because they(we) always end up nuking them(our)selves.
It's either that or wait 5 billion years for Sol to engulf the earth in all it's gigantic red glory.
I must gain objective knowledge of the origin of all space, time, matter and energy, including me, the knower himself, and no rinky-dink little backwater planet overpopulated with superstitious primitives is going to stop me! Igor, the switch!
Beauty. This deserves to be in a fortune file.
It seems ~90% of Slashdot readers side with the scientists, but I wonder if there isn't a real concern here. This is something that you would have to be a scientist just to make a judgement on, though, so I suppose we are stuck with their discretion, whether we like it or not. Let's just hope that they aren't Mad Scientists!
--Lenny "A good machine dreams of the day it will be replaced by a better machine." --Douglas Coupland
Competent people lack the necessary expertise in areas such as these. Due to a strange quirk in science, breakthroughs with dangerously unstable AI's are done only by eccentric but brilliant solitary researchers.
Black Hole? (Score:0) by Anonymous Coward on Monday October 11, @04:53PM EDT (#46)
I have always had the insane wish to destroy the world... well, actually my first aim was to take it over, but after a while I realized that that could have been boring due to the sheer amount of people around me and I deemed more interesting destroying it as a whole... First attempt was about a nice and small nuclear war... at least before I realized that somebody could actually survive the radioactivity... too bad. Time to think about something more grand, like a tiny asteroid (7-8 miles in radius) hitting the west coast of north america (it does not really matter where it is going to hit... still that would be a nice counterpart to the gulf of Mexico)... the odds of getting any survivor in this scenario are nicely low... but you are not guaranteed that in let's say half a billion years something very similar to what humankind is right now will develop... woe is me! Third idea was a small star going nova, and incidentaly wiping out all the inner solar system... wonderful special effects and one hundred per cent guaranteed effectiveness... still does anybody know how to get the sun go nova? (details... small details... I hate details... by the way... even attracting an asteroid could be tricky!)... But now I read about this! A black hole!! Yes!!! The mareal forces it would generate should be more than enough in order to rip the planet apart before swallowing it... total and definitive distruction... annihilation of the matter itself... and there is a possibility the technology is already here!!! What could I ask more? I know it will not be easy, but there is hope... Just a few order of magnitude more energy (I daresay 10^10 should be enough for a start) and then... a dream cames true!
The Sagan idea doesn't work with this. Even if the Earth became a black hole, there would be evidence of humans having existed. Earth would be a black hole with the same gravitational pull as it has now, just no size and an accessible event horizon.
It would be a black hole with a moon and satelites, some of them artificial.
And when physicists talk about "small but non-zero probablility" remember that there is a small but non-zero probability that a baseball-sized chunk of the Sun will appear on your desk within the next five minutes, due to quantum effects.
When these guys say "small", they mean it.
Fear my wrath, please, fear my wrath? Homer My email address is live, as is.
Probability... (Score:0) by Anonymous Coward on Monday October 11, @05:05PM EDT (#53)
Probabilities are jokes! Even when you say that an event has "probability zero" of occurring, still there is an infinity of cases it can happen... just they form a set of "mesure zero", but in the same sense as `the area of a line is zero'... The only thing a probability tells you is the likeness of something to happen, not whether it is going to or not. The likeness of an event like the one depicted in the article is definitely low... unless you have a nice starship powered by an "infinite inprobability drive" :))
Basic lesson in probability here. If an event has probability zero, it will never occur. Ever. If anyone ever told you an event had probability zero and it did occur, they were an idiot.
Sorry, this will probably be rated as flamebait, but I can't stand when people who don't understand probability and statistics write it off as bullshit simply because they don't understand.
I strongly recommend the book Innumeracy by John Allen Paulos to anyone who has a problem with statistics. Maybe it won't teach you the subject in great detail, but it WILL show you how easily you can be ripped off by not understanding statistics. (Good read even if you think you already know.)
Sorry about the rant, but I come from a profession where manipulation and fabrication of figures (as is done by marketers to attract the public) would quickly end any prospects of future employment.
Re:Probability... (Score:0) by Anonymous Coward on Monday October 11, @06:09PM EDT (#112)
I wold suggest you rather any basic book on geometric measure theory (and/or on probability measures, if you wish). A probability is defined as the measure of a set in a given space. Depending on the space and on the set you choose what I wrote before is true. [e.g. any set with a denomberable number of elements has Lebesgue mesure equal to 0 in a Real vector space... still it is not empty]
"[e.g. any set with a denomberable number of elements has Lebesgue mesure equal to 0 in a Real vector space... still it is not empty]"
But then the probability density isn't zero. In that case, you're not looking for the probability of a specific event, but of a range of events. Mind you, this is headed off-topic very quickly, but there are cases where even the probability density is zero--such as the probability density of finding a particle in the node of the corresponding wavefunction. The particle will never be found at such a location.
I see what you are saying, but this leads into studying the Surreal Numbers. Is a differential or infinitessimal probability the same as no probability? I think not.
"Basic lesson in probability here. If an event has probability zero, it will never occur. Ever. If anyone ever told you an event had probability zero and it did occur, they were an idiot."
Events of probability zero can occur. In fact some of them happened today.
Proof:
Checking the weather data for my city, i see that at 3 PM, the temperature was 82 F, and at 5 PM, it was 79 F. These are not exact values, so let us assume that the temperature was between 81 and 83 at 3 PM and between 78 and 80 at 5 PM.
By the Intermediate Value Theorem, we see that the temperature must have been exactly 80.5 at some time between 3 and 5 PM. (Assuming that temperature behaves continuously, of course.)
Now, assuming that f is the probability density function for temperature in my area, the probability that the temperature is exactly 80.5 at any given time is
P(80.5 = T = 80.5) = int{80.5, 80.5} f(x) dx [1]
Since the limits are the same, the integral is zero (by FTC, re-take Calculus I for details).
The temperature *was* exactly 80.5 at some time today, yet the probability of it being so was zero.
Thus, event of probability zero can happen.
(This is hardly a rigorous proof. I have assumed several things, including the assumption that temperature is not quantized, but i hope the point is taken.)
-- Mike
P.S. I do not believe myself to be an idiot. (However, i do not have a proof of this.)
-- Mike
[1] p 131 _Probability and Statistics for Engineering and the Sciences_, Jay L. Devoe, Brooke/Cole 1991.
Hmm, reminds me of Dirac delta functions and other such oddities which are not mathematicaly *nice.* I think that there is a whole branch of quasi-mathematics dealing with these monsters. I think that they chose the name *generalized functions.*
Since the limits are the same, the integral is zero (by FTC, re-take Calculus I for details).
If I recall correctly, the integral approaches zero as the number of steps approaches infinity. Usualy, that's just a technicality, and saying "the integral is" is the same as saying "the integral approaches". But when things get weird, the picky details get significant.
On the other hand, it's been a few years and I could be completely wrong.
Fear my wrath, please, fear my wrath? Homer My email address is live, as is.
If I recall correctly, the integral approaches zero as the number of steps approaches infinity. Usualy, that's just a technicality, and saying "the integral is" is the same as saying "the integral approaches". But when things get weird, the picky details get significant.
No, no. This integral is exactly zero. You may be thinking of the definition of the Riemann Integral. The Riemann Sums approach the value of the integral as the number of data points approaches infinity.
Integrals, however, do not approach values. The Riemann Integral (which is the one you used in Cal I) explicitly *contains* a limit as n --> infinity. The value of an integral is either a fixed constant, or else the integral diverges (The limit either exists, or it does not).
Remember also that the value of an integral is equal to the area under the curve. An integral with limits the same should be equal to the area of a region with width zero, that is 0. (Here we assume the integral exists and therefore the curve has no singularities.)
"Checking the weather data for my city, i see that at 3 PM, the temperature was 82 F, and at 5 PM, it was 79 F. These are not exact values, so let us assume that the temperature was between 81 and 83 at 3 PM and between 78 and 80 at 5 PM.
By the Intermediate Value Theorem, we see that the temperature must have been exactly 80.5 at some time between 3 and 5 PM. (Assuming that temperature behaves continuously, of course.)
Now, assuming that f is the probability density function for temperature in my area, the probability that the temperature is exactly 80.5 at any given time is
P(80.5 = T = 80.5) = int{80.5, 80.5} f(x) dx [1]
Since the limits are the same, the integral is zero (by FTC, re-take Calculus I for details).
The temperature *was* exactly 80.5 at some time today, yet the probability of it being so was zero." OK, let's look at this. The temperature, as you stated is not precise. Stating that the recorded temperature "is" a certain number really means that the temperature lies within a finite interval containing that number. Thus, a finite probability rather than a zero probability.
On the other hand, I would agree with you--provided that temperature is indeed continuous wrt time. However,this still leaves the problem of whether the temperature is exactly 80.5 for any finite amount of time. In order for this to be possible, clearly some nth derivative of the function is not continuous.
"P.S. I do not believe myself to be an idiot. (However, i do not have a proof of this.)
-- Mike"
I believe myself to be an idiot. (I just need to find one counterexample to disprove this. Sounds easier than your way.)
On the other hand, I would agree with you--provided that temperature is indeed continuous wrt time. However,this still leaves the problem of whether the temperature is exactly 80.5 for any finite amount of time. In order for this to be possible, clearly some nth derivative of the function is not continuous.
Now we're starting down the road toward deep metaphysics. For instance:
1. If an event has a duration of zero, did it actually happen? What is the meaning of an instataneous measurement?
2. Since we cannot measure temperatures with ultimate percision, does it make sense at all to say that a temperature is exactly any number? Should a continuous random variable always be confined to a range?
3. Since temperature is a macroscopic phenomenon, does it make sense to apply ultimate percision to it at all? Would the concept of temperature disappear under infinitesmal scrutiny like length does? (See "How Long is the Coastline of Britian?", Benoit Mandelbrot.)
It was never my intention to launch a philosophical discussion. I was just trying to point out that the statement "Zero proability events can occur." is not idiotic. I can easily demonstrate such a case in mathematics, but whether or not you believe it happens in reality is a matter for your personal metaphysics.
"P.S. I do not believe myself to be an idiot. (However, i do not have a proof of this.)
-- Mike"
I believe myself to be an idiot. (I just need to find one counterexample to disprove this. Sounds easier than your way.)
--Chris
...and this of course get us into deep epistimology, the arguments hinging mostly on the definition of "idiot" and the possibility that a true idiot could convince himself that an invalid proof of non-idiotness was valid.
An alien visit to this system would be interesting.
"Commander, we have found several artificial space probes in and near this system, constructed by what appears to be an intelligent species."
"yes, but where is the homeworld, did they develop FTL technology and leave?"
"no, we believe that the secondary, the black hole, is too small to be naturally formed, and it's trajectory, calculated retroactively indicates that it is the origin point for the space probes."
"then. . ."
"yes, another one bites the dust."
"damn, why don't these primatives LEARN what not to mess with?"
"The number of suckers born each minute doubles every 18 months." -jafac's law
(Don't take this as doom-saying about the work at Brookhaven or any specific project, it's meant as a general discussion.)
As we begin to control greater energies, we seem to be entering a time when some scientific experiments will entail small, but non-zero, risk to people in the area, maybe even to humanity at large.
How small of a probability of disaster does it take before we can justify a certain amount of risk, and how do we estimate the probability of disaster without a large number of trials?
For instance: IIRC, pre-Challenger the official estimates on the Space Shuttle having a fatal accident were supposed to be something like one in a million. (My copy of What Do You Care What Other People Think? is at home, feel free to correct me on the real number.) How do you get that estimate? Best way would be to launch a million times and see what happens, but that's hardly practical. Instead it was based on engineering knowledge of well-understood physical principals, materials, and techniques. But it was completely wrong, extrapolation on top of extrapolation without even a propagation of errors. How much worse are our chances of predicting the risks of new techniques, new materials, even new physics?
Of course, the fine and noble folks onboard the shuttle knew that there was a risk, and volunteered to take it. What about "innocent" bystanders? The probability of a fatal accident during the Cassini launch or flyby may have been one in a million (or, it may have been much greater - NASA's "Cassini Mission False and True" says "the navigation accuracy of NASA spacecraft is better than 20 km." Or is that 20 miles?), but it was never non-zero. No launch has a non-zero risk - there's some small chance of a chain of malfunctions that crashes the thing into someone's house. How small do we have to get the risk to justify the experiment?
I'm not going to lose any sleep over the Brookhaven work - given what we know about cosmic rays, I'd say the risk is greater that I'll be hit by a metorite than that there will be any problems there. But the questions of risk to the public will remain.
Tom Swiss | the infamous tms | http://www.infamous.net/ "What's so funny about peace, love, and understanding?" - Nick Lowe
Even if the Earth became a black hole, there would be evidence of humans having existed. Earth would be a black hole with the same gravitational pull as it has now, just no size and an accessible event horizon.
It would be a black hole with a moon and satelites, some of them artificial.
Given that the collapse of the Earth into a black hole would involve the conversion of perhaps 50% of the total mass into energy in the accretion disk, all the artificial satellites would probably evaporate. And with the combined effects of the radiation evaporating the surface layers (producing thrust) and the loss of gravitational pull, if the Moon did not just vanish it might well achieve escape velocity and go sailing around on its own. I should run the numbers, but I'm tired. -- Deja Moo: The feeling that you've heard this bull before.
Given that the collapse of the Earth into a black hole would involve the conversion of perhaps 50% of the total mass into energy in the accretion disk, all the artificial satellites would probably evaporate.
...assuming isotropic radiation, thus accreating according to Eddington. All observed black hole candidates however show jet forming (ie anisotropic 'dynamo-like' effects), from the small to the very large Active Galactic Nuclei in the center of galaxies.
Ivo
We are all in the gutter, but some of us are looking at the stars
Let's say that the radiation intensity is such that the energy dumped out on the equator is 0.01% as intense as the total average flux. If all of earth falls into a black hole and the conversion efficiency is 50%, the total energy is about 6e24kg * 9e16 * 0.5 = 2.7e41 joules. Assuming a nice geosynchronous orbit at 42000 km radius, the energy flux would be 2.7e41 * 1e-4 / (4 * pi * 4.2e7^2) = 1.2e21 J/m^2. Conclusion: Any satellite orbiting at that altitude would be vaporized.
The Moon would take a hammering of about 1e19 J/m^2 on the Earth-facing side. The entire near side would also be vaporized, along with every trace of human activity on the Moon. It would also receive a hell of a kick. I don't know if it would hold together or be blown to pieces, but I'm absolutely certain that it would not remain in orbit around the former Earth.
Mars, at some 40 million miles away at closest approach, would get about 1/40000 as much flux as the Moon at the worst. That's still on the order of a megaton per square meter! Just face it, if any planet in the Solar system went down a black hole, the entire neighborhood would be a pretty unhealthy place to be for the duration. -- Deja Moo: The feeling that you've heard this bull before.
.. but not for artificial satellites ;-p. Hokay the numbers are huge, I agree. But anisotropy does much more than dividing the radiation number by x. Besides that there are several important complications to your lucent but very crude calculations.
- since most matter falling into the black hole is cold and already very deep in the potential well conversion effeciency will very much lower than the theoretically infinite distance approach
- all the mass surrounding the earth center carries angular momentum, the accretion disk into which the earth will transform will only on convert some small fraction of the potential energy of the accreting mass. Besides in our scenario we assume the mini black hole to originate at the earth's surface further decreasing the accretion rate and conversion efficiency. We are not talking about a hardly rotating collapsing stellar iron core here...
- the black hole might starve before it can eat all of its food. After accretion disk forming only the inner 3*R(schwarzschild) orbits are unstable. Then angular momentum transport in the accretion disk will dictate the rate of energy production.
- much of the available gravitional energy will be converted into kinetic energy blowing a significant portion of the mass away in opposite jets
- the evaporated mass of the earth will consist of small iron and silicate particles creating a broad inpenetratable dust band on the equator just as seen AGNs. Given the available Si/Fe mass and high density you may happily assume that .01% of your overstimated radiation at the equator might be several orders of magnitude too high. Silicate grains are magnificent UV absorbers, and UV-soft Xray will be the major emission waveband in the accretion disk.
My conclusion is that the earth satellites probably wont survive, but the Moon and Mars will laugh at Earth's misery. Especially since the momentum carried by the rest radiation will be ridiculously small compared to their orbital momentum.
Ivo
We are all in the gutter, but some of us are looking at the stars
.. but not for artificial satellites ;-p. Hokay the numbers are huge, I agree. But anisotropy does much more than dividing the radiation number by x. Besides that there are several important complications to your lucent but very crude calculations.
If you want to have a calculating battle, by all means jump in. I'm willing to fire off numbers at you and take your return fire, winner to collect a pitcher of beer from the loser if they should ever be in the same city. I admit that this wouldn't be much of a prize for you since I am not likely to visit the Netherlands soon and American beer being as lousy as it is, but I can't think of another prize worthy of a friendly competition.
That said, the numbers are not just huge. They are many orders of magnitude beyond huge. For instance, the megaton/m^2 flux at Mars is enough energy to blow off an atmosphere as thick as Venus'. 1 megaton = 4.2e22 ergs = 4.2e15 joules.
- since most matter falling into the black hole is cold and already very deep in the potential well conversion effeciency will very much lower than the theoretically infinite distance approach
Nope. The gravitational energy available goes as 1/r, so a full 50% of the total is available from only 2 radii out. The radius of a 1-earth-mass black hole is about 1 centimeter; everything is going to be falling in from more than twice that!
- all the mass surrounding the earth center carries angular momentum, the accretion disk into which the earth will transform will only on convert some small fraction of the potential energy of the accreting mass. Besides in our scenario we assume the mini black hole to originate at the earth's surface further decreasing the accretion rate and conversion efficiency. We are not talking about a hardly rotating collapsing stellar iron core here...
Even at the equator, an object sitting on the ground has only enough angular momentum to maintain a circular orbit around an earth-mass point at 1/64 of the radius of the Earth. And that's the best an object on Earth can do! Things at the poles would fall straight down if they were suddenly unsupported.
Conversion efficiency is supposedly up to 50%. All the mass cramming into that accretion disk at a large fraction of c generates a heck of a lot of heat.
The mini-BH would fall from the surface of the earth toward the core (if it could last long enough to get out of the lab, which it could not), and as it absorbed mass it would also absorb the momentum of that mass. Unless there is a transfer of momentum, the center of mass of the system would remain on the same path. This means that the mini-BH would very quickly wind up stationary at the center of the Earth.
Earth isn't very big, and doesn't have a lot of angular momentum compared to a star of far greater dimensions. If something swallowed the core, the rest would fall inward just fine.
- the black hole might starve before it can eat all of its food. After accretion disk forming only the inner 3*R(schwarzschild) orbits are unstable. Then angular momentum transport in the accretion disk will dictate the rate of energy production.
The black hole couldn't starve unless the accretion disk could transfer enough angular momentum outward to get the remaining mass into orbit. Without that, the inward pressure of the falling mass would only be balanced by radiation pressure from the accretion disk. Since an object on the equator only has the angular momentum to maintain a circular orbit at 1/64 of an Earth radius, at least 99.9996% of the Earth would be able to fall into the BH unless prevented by other mechanisms.
- much of the available gravitional energy will be converted into kinetic energy blowing a significant portion of the mass away in opposite jets
The jets are driven by radiation pressure. The jets will also be there to scatter the energy radiated poleward from the accretion disk and allow it to hit objects behind the accretion disk. Remember, my calculations only assumed that 0.0001 of the total energy escaped as radiation toward the equator. The same conclusions hold pretty much even if you reduce that to 0.00000001.
- the evaporated mass of the earth will consist of small iron and silicate particles creating a broad inpenetratable dust band on the equator just as seen AGNs. Given the available Si/Fe mass and high density you may happily assume that .01% of your overstimated radiation at the equator might be several orders of magnitude too high. Silicate grains are magnificent UV absorbers, and UV-soft Xray will be the major emission waveband in the accretion disk.
See my previous comment about scattering efficiency and losses.
My conclusion is that the earth satellites probably wont survive, but the Moon and Mars will laugh at Earth's misery. Especially since the momentum carried by the rest radiation will be ridiculously small compared to their orbital momentum.
I didn't say that Mars would be knocked out of orbit, I implied that the side facing Earth would be pretty thoroughly fried (a megaton/m^2 will do that). I'm pretty certain now that both Mars and Venus would lose their atmospheres (maybe only half of Venus, if the event went quickly).
Were it possible for this to happen, the Solar system would not be a healthy place to be that day. It would be best to be somewhere far away on vacation, and deal with the insurance agent upon your return. And hope you have a "full replacement planet" policy. ;-) -- Deja Moo: The feeling that you've heard this bull before.
If you want to have a calculating battle, by all means jump in. I'm willing to fire off numbers at you and take your return fire, winner to collect a pitcher of beer from the loser if they should ever be in the same city. I admit that this wouldn't be much of a prize for you since I am not likely to visit the Netherlands soon and American beer being as lousy as it is, but I can't think of another prize worthy of a friendly competition.
Hehe, noted. You're welcome to have a beer anyway ;-p.
But seriously:
That said, the numbers are not just huge. They are many orders of magnitude beyond huge. For instance, the megaton/m^2 flux at Mars is enough energy to blow off an atmosphere as thick as Venus'. 1 megaton = 4.2e22 ergs = 4.2e15 joules
Eye know about huge, I was just disagreeing how huge. Eating off zeros on the way.
Nope. The gravitational energy available goes as 1/r, so a full 50% of the total is available from only 2 radii out. The radius of a 1-earth-mass black hole is about 1 centimeter; everything is going to be falling in from more than twice that!
..assuming the black hole already contains the earth mass, which is not the case. My point is that since it begins small, in a dusty rotating environment, the black hole will end up with only a small fraction of the mass.
1.Even at the equator, an object sitting on the ground has only enough angular momentum to maintain a circular orbit around an earth-mass point at 1/64 of the radius of the Earth. And that's the best an object on Earth can do! Things at the poles would fall straight down if they were suddenly unsupported.
1/64 Earth radius is 10.000.000 Schwarzschild radii of an 1-earth-mass black hole (which does not exist at the time). I fail to see how it would find its way directly to the black hole (without an up-to-date inner-planetary map that is)
2.Conversion efficiency is supposedly up to 50%. All the mass cramming into that accretion disk at a large fraction of c generates a heck of a lot of heat.
Again I disagree. I'm not talking about forming a M-earth BH and subsequently letting testparticles fall into it. Only matter with small enuff angular momentum to hit the Kerr-radius directly will be eaten instantly. The earth will form an accretion disk extending from 100km to lets say a 100m, depending on radiation pressure. Free falling angular momentum carrying mass from 6000km out to 50km (not into the black hole!) speeds up to a small nowhere near a fraction of C. Your free-fall calculation does not include the centrifugal potential. Again our main difference is that I suggest that the accretion disk at the time of creation will contain almost all of the Earth's mass (lemme throw you a number 99.9999998% ;-p). You seem to calculate from an existing M-earth BH.
3.The mini-BH would fall from the surface of the earth toward the core (if it could last long enough to get out of the lab, which it could not)...
Ofcuz. In our lively discussion I also forgot to stress that the damn thing would evaporate instantly anyway. This triggers another question, mebbe you can shed some light on this. How big must the progenitor BH be for the inbound mass flux (in the beginning dominated by free fall to the earth's center and the Rschwarz of the progenitor) to balance the evaporation mass flux?
4.Earth isn't very big, and doesn't have a lot of angular momentum compared to a star of far greater dimensions. If something swallowed the core, the rest would fall inward just fine.
Absolute ang momentum is irrelevant. Only the effective potential matters, and centrifugal component plays a crucial role. Earth spins about 30 times faster than the Sun.
The black hole couldn't starve unless the accretion disk could transfer enough angular momentum outward to get the remaining mass into orbit...
Now this is strange. Are you actually saying that angular momentum transfer helps the BH to starve? Or is there some wrong with my English? In standard thin disk accretion theory quasi-viscous ang momentum transfer is the only way to prevent it from starving. Accretion effeciency computed from the marginally stable orbit is only a few %. Bring in mind that the Kerr-radius is ridiculously small compared to the size of the accretion disk.
The jets are driven by radiation pressure. The jets will also be there to scatter the energy radiated poleward from the accretion disk and allow it to hit objects behind the accretion disk. Remember, my calculations only assumed that 0.0001 of the total energy escaped as radiation toward the equator. The same conclusions hold pretty much even if you reduce that to 0.00000001.
Two possibilities of Jet generation have been discussed in literature. The most important being magnetic field line winding and flux freezing wich will tend to make plasma stream along the field lines. It is thought that this dynamo-effect causes the bulk relativistic motion we call a jet. The radiation pressure only provide the initial acceleration to produce the outflow. That scattering on the jet will contriblute significantly to the overall radiation is unsupported by observations of real jets. My point is that given your severe overestimation of the radiated energy (calculated from a unrealistic simple scenario) and the chaotic poorly understood magnetic effects, the acretion scenario, the absorption of the dust band (which will be created) will provide anuff extra "couple of zero's" to topple your argument.
Especially the dust band is a nice one. The amount of extinction might be 100-300 magnitudes in UV/X-ray. I do not need to remind you what that means to the flux. But to all non-astrophysists: this means that only 0.00000000000000000000000000000000000001% of the radiation gets through. Ofcourse I'm not saying anything about the re-radiated IR radiation hehehheeh.
Love them zero's. How 'bout a beer? ;-p
Ivo
We are all in the gutter, but some of us are looking at the stars
Since you are under the impression that you've provided a counter-calculation, but you haven't produced anything resembling one and have missed the point in several other areas, I think you might have had too many beers already. You began celebrating just a wee bit too soon.
Eye know about huge, I was just disagreeing how huge. Eating off zeros on the way.
How can you "eat zeroes" without calculating? Bah.
Nope. The gravitational energy available goes as 1/r, so a full 50% of the total is available from only 2 radii out. The radius of a 1-earth-mass black hole is about 1 centimeter; everything is going to be falling in from more than twice that!
..assuming the black hole already contains the earth mass, which is not the case. My point is that since it begins small, in a dusty rotating environment, the black hole will end up with only a small fraction of the mass.
No, it would begin small, in the middle of a rather dense planet. As soon as it got as big as the distance between atoms in the core, matter would begin falling into it at the speed of sound. So long as it sat at the middle of a large semi-liquid mass, nothing would stop it from growing. The only way for it to stop growing would be for the remaining mass to be either
spun up from the contraction of its radius so that it achieves orbit, or
blown off into a jet.
1.Even at the equator, an object sitting on the ground has only enough angular momentum to maintain a circular orbit around an earth-mass point at 1/64 of the radius of the Earth. And that's the best an object on Earth can do! Things at the poles would fall straight down if they were suddenly unsupported.
1/64 Earth radius is 10.000.000 Schwarzschild radii of an 1-earth-mass black hole (which does not exist at the time). I fail to see how it would find its way directly to the black hole (without an up-to-date inner-planetary map that is)
It'll find its way by gravitational attraction, and again you miss the point. It doesn't matter how many Schwarzchild radii that is; absolutely nothing on Earth could achieve an orbit farther out than that on its own angular momentum, so everything else would either be pushed into the BH by the pressure of the matter above it or blown off in one of the jets.
About the best an object anywhere on the surface of Earth could do is to find an orbit at about 1/64 of its original radius (and that's the best). Since the volume of a sphere scales as r^3, chopping the radius of a sphere by 63/64 eliminates 262143/262144 of its volume. That's about 99.9996%.
2.Conversion efficiency is supposedly up to 50%. All the mass cramming into that accretion disk at a large fraction of c generates a heck of a lot of heat.
Again I disagree. I'm not talking about forming a M-earth BH and subsequently letting testparticles fall into it. Only matter with small enuff angular momentum to hit the Kerr-radius directly will be eaten instantly. The earth will form an accretion disk extending from 100km to lets say a 100m, depending on radiation pressure. Free falling angular momentum carrying mass from 6000km out to 50km (not into the black hole!) speeds up to a small nowhere near a fraction of C. Your free-fall calculation does not include the centrifugal potential. Again our main difference is that I suggest that the accretion disk at the time of creation will contain almost all of the Earth's mass (lemme throw you a number 99.9999998% ;-p). You seem to calculate from an existing M-earth BH.
I made no such assumption. I assumed only that any BH created at rest with respect to the surface of the earth would fall inward, and everywhere it went it would have plenty of matter to eat. As for the centrifugal potential, it would only make a difference if the angular momentum could not be dissipated against the matter further above. As angular momentum and energy are lost to friction, the matter spirals in.
Ofcuz. In our lively discussion I also forgot to stress that the damn thing would evaporate instantly anyway. This triggers another question, mebbe you can shed some light on this. How big must the progenitor BH be for the inbound mass flux (in the beginning dominated by free fall to the earth's center and the Rschwarz of the progenitor) to balance the evaporation mass flux?
I have no idea. I've lost the equation for the evaporation rate of a BH, and since the Hawking radiation would tend to push things away the calculation is too complex for a simple discussion like this one. Now, if I were going for my PhD in physics I might do it as part of my thesis project, but I'm not.
4.Earth isn't very big, and doesn't have a lot of angular momentum compared to a star of far greater dimensions. If something swallowed the core, the rest would fall inward just fine.
Absolute ang momentum is irrelevant. Only the effective potential matters, and centrifugal component plays a crucial role. Earth spins about 30 times faster than the Sun.
The black hole couldn't starve unless the accretion disk could transfer enough angular momentum outward to get the remaining mass into orbit...
Now this is strange. Are you actually saying that angular momentum transfer helps the BH to starve? Or is there some wrong with my English? In standard thin disk accretion theory quasi-viscous ang momentum transfer is the only way to prevent it from starving. Accretion effeciency computed from the marginally stable orbit is only a few %. Bring in mind that the Kerr-radius is ridiculously small compared to the size of the accretion disk.
There's your error. You are assuming the matter is accreting from a thin disk (which is already in orbit). This assumption is not valid; it would be accreting from a nice, fat, spherical planet with a core of iron atoms at perhaps 10 grams/cc. To get to the thin-disk case, most of the planet would have to be either sucked down the BH or blown off in jets. Transfer of angular momentum outward works to give the remaining matter orbital velocity at a greater radius. It doesn't matter how small the Kerr radius is as long as there is a huge quantity of matter under pressure squeezing itself into the BH like water through a faucet.
The jets are driven by radiation pressure. The jets will also be there to scatter the energy radiated poleward from the accretion disk and allow it to hit objects behind the accretion disk. Remember, my calculations only assumed that 0.0001 of the total energy escaped as radiation toward the equator. The same conclusions hold pretty much even if you reduce that to 0.00000001.
Two possibilities of Jet generation have been discussed in literature. The most important being magnetic field line winding and flux freezing wich will tend to make plasma stream along the field lines. It is thought that this dynamo-effect causes the bulk relativistic motion we call a jet. The radiation pressure only provide the initial acceleration to produce the outflow. That scattering on the jet will contriblute significantly to the overall radiation is unsupported by observations of real jets. My point is that given your severe overestimation of the radiated energy (calculated from a unrealistic simple scenario) and the chaotic poorly understood magnetic effects, the acretion scenario, the absorption of the dust band (which will be created) will provide anuff extra "couple of zero's" to topple your argument.
Especially the dust band is a nice one. The amount of extinction might be 100-300 magnitudes in UV/X-ray. I do not need to remind you what that means to the flux. But to all non-astrophysists: this means that only 0.00000000000000000000000000000000000001% of the radiation gets through. Ofcourse I'm not saying anything about the re-radiated IR radiation hehehheeh.
Ah. So you admit attempting to obfuscate the issue. Sorry, it doesn't win any points (or brew). ;-)
Another model just occurred to me: the radiation pressure of the growing BH and its polar jets blows the remains of Earth into a boiling, seething mass of iron-silicate vapor. The heat from this melts the remaining artificial satellites and then coats them with molten goo, as well as stealing their angular momentum from gas drag and pulling them in to share the fate of their creators. The entire Moon gets coated in iron, which simultaneously obliterates all traces of Apollo and turns it into a shiny marble for the next several billion years. ;-) -- Deja Moo: The feeling that you've heard this bull before.
Since you are under the impression that you've provided a counter-calculation, but you haven't produced anything resembling one and have missed the point in several other areas, I think you might have had too many beers already. You began celebrating just a wee bit too soon.
Now that's not so nice... ;-( I started out because your initial posting was a wee bit crude in energy budget and wrong in scenario, to my taste. If you think this discussion is tiresome you shouldn't invite me to reply. I've got better things to do but to irritate you, reeeeally.
Especially the dust band is a nice one. The amount of extinction might be 100-300 magnitudes in UV/X-ray. I do not need to remind you what that means to the flux. But to all non-astrophysists: this means that only 0.00000000000000000000000000000000000001% of the radiation gets through. Ofcourse I'm not saying anything about the re-radiated IR radiation hehehheeh.
Ah. So you admit attempting to obfuscate the issue. Sorry, it doesn't win any points (or brew). ;-)
Nah, just remembered that something had to happen to absorped energy. First effect is to puff up the dust donut. But after this it will loose energy in intense IR radiation, just as seen in the FIR galaxies.
Another model just occurred to me: the radiation pressure of the growing BH and its polar jets blows the remains of Earth into a boiling, seething mass of iron-silicate vapor...
Funny thing is that I was thinking 'bout the same thing on my way home yesterday. You know it is impossible that the Earth will collaps into the BH. This you must admit (altho you have been as stubborn as I am). Gravitational collaps with the outer matter pushing the inner matter without delay into the BH hole only works at a mass density close the critical value for a body to lie within it's own horizon. Direct formation of small black holes is extremely difficult.
Do you want a calculation? Critical density scales as M^-2 and has the density of 10g/cm^3 for a 10^7Msun Black hole candidate. For direct formation (collapse) of an Earth BH (Mearth = 3.10^-6Msun) you require a core density of roughly 10^24g/cm^3. This cant be obtained, at least not with our type of matter.
Therefore we need to have some sort of accretion scenario. Since we have spherical symmetrical mass distribution the maximum accretion speed is defined by the Eddington limit, where radiation pressure of the infalling inner layer and the pressure of the layer just outside it balance (in this scenario dominated by the pressure of the rest of the Earths mass above it). This effect starts immediately, and will generate the pressure to support the rest of the core and prevent it from collapsing. If you dont believe this, check every standard literature on gravitational collapse, black hole formation and Eddington accretion. Blowing off the outer layers is a possibility, but this requires super-Edington accretion (achievable in highly anisotropic situations), since you need more outward radiation pressure than supplied by the default balanced influx.
Eddington accretion and Lifetime: There exist a maximum luminosity that can be radiated by a gravitating body of mass M. This limit arises because radiation pressure from a central source can not exceed the gravity of the infalling material and the excess pressure from the material above it (then it would starve). Although the actual value for the Luminosity is hard to calculate, because of the complicate environment in the earth's core, it is interesting to note that the lifetime of een object radiating at the Eddington limit is independent of mass. The lifetime (know as the Salpeter time) is proportional to Mc^2/Ledd and for silicate particles this might be anyware between 10^6-10^8 years. 10^8 for free-fall, 10^6 for solid object.
I suppose my story sounds a bit dull compared to the spectacular 'blowing the face of the moon' scenario, but I think that you will study the relevant literature you find that direct collapse is impossible.
I admit that some of my earlier objections were wrong, but hey they came only from the tip of my hat. ;-p
The problem is that altho your total total energy budget might be correct (within a factor of 1000 or so), your calculations about the effects on the moon need this energy to be released almost instantly. From the Salpeter lifetime however it is more likely that this will take millions of years. This is supported by all observations of actual BH and AGN canditates. Eye know that the actual accretion scenarios are different, but that is accounted for by taking enhanced isotropic accretion with silicate particles. (else you would end up with typical 10^12 yr lifetimes)
The heat from this melts the remaining artificial satellites and then coats them with molten goo, as well as stealing their angular momentum from gas drag and pulling them in to share the fate of their creators. The entire Moon gets coated in iron, which simultaneously obliterates all traces of Apollo and turns it into a shiny marble for the next several billion years. ;-)
Hehe, I must say that IS an actractive and esthethic thought. But again this requires extreme super-Eddington accretion and this is difficult to achieve.
My best guess is that the BH settles in the Earth's core, slowly accreting the mass because of the inevitable balance between radiation pressure and infalling material (pressure by the outer-layer does not change this, only the increases required radiation level and speeds up the lifetime by a million or so). The heat would slowly dissipate through to the Earth crust, making global warming more like global cooking. The seas will evaporate, we will melt. The Earth might resemble Venus within a few 1000 years. However I think that given the fact that the total radiated energy is smeared out over millions of years, the Moon for example will be able to keep kewl, just by thermal equilibrium.
Damn, got a dry mouth. Could use a beer tho.
Ivo
We are all in the gutter, but some of us are looking at the stars
After taking a few more factors into account, I have to agree with you. For instance: sonic speed limits of infalling material. Assuming that the speed of sound is 10 km/sec and the Kerr radius is 2 um (about a 1e-4 M-E mass), the volume falling into the BH would be 4/3 * pi * 8e-18 * 1e4 = ~3e-13 m^3/sec. That is perhaps 3e-9 kg/sec. Heating of the infalling material would reduce the accretion rate further, since the density falls faster than the speed of sound rises. I know I'm not taking degeneracy of highly compressed matter into account, but it would take a lot more than that to speed things up to a progression in less than millions of years.
As for the "seething ball of iron silicate" scenario, if energy could be transferred outward fast enough (say, from convection outside of the radiative zone) this would be possible, but you appear correct that this requires a rate of heat generation too high for a mini-BH to manage by accretion. Even if all of 3e-9 kg/sec was converted to energy, this would only yield 2.7e10 watts, or about the solar energy falling on 20 km^2 of the top of the atmosphere. A trifling amount. Next mystery: What would a decaying mini-BH (say, 1 million tons) do if it happened to be inside a planet when it went boom?
That was educational. Pitcher of Heineken? -- Deja Moo: The feeling that you've heard this bull before.
Free falling angular momentum carrying mass from 6000km out to 50km (not into the black hole!) speeds up to a small nowhere near a fraction of C.
Yes. It would get up to about 120 km/sec on the basis of its gravitational potential. It would only get to a large fraction of c within a few hundred meters of the BH. More to the point, an object on the equator moving tangentially at 1600 kph and allowed to ride inward on the surface of a frictionless sphere toward a point mass of 1 M-E (losing energy but maintaining a constant angular momentum) would achieve orbital velocity of about 30 km/sec when it had fallen to about 100 km radius. Anything inside this radius would have to fall even further, or get angular momentum and energy from somewhere else, to avoid being pulled (or pushed) even further inward. -- Deja Moo: The feeling that you've heard this bull before.
The Sagan idea doesn't work with this. Even if the Earth became a black hole, there would be evidence of humans having existed. Earth would be a black hole with the same gravitational pull as it has now, just no size and an accessible event horizon.
Actually, in this scenario, the Sagan principle still works. As long as the destruction transmutes a civilization from an entity or object discernable as such (ie cities, a planet giving off a star's radio energy, etc) to one not decernable as such by the target civilization (ie us), then it has for all intents been destroyed.
Now if at some future point we as a people became more astute at recognizing fallen civilizations (destroyed by nuclear war, black holes, CmdrTaco, what have you), then Sagan's principle would no longer be valid, because there would be no civilizations that could disappear after being formed.
I know that we 'believe' that black holes exist, but, what I am wondering is why, if they continue to gain mass and their event horizon increases exponentially, we haven't yet been sucked up by a neighboring hole.
Wouldn't it make sense that, these black holes out there would eventually all converge together, gaining mass and 'size', presumably even increasing escape velocity?
Can someone explain why this hasn't happened yet? Or let me know exactly when it will happen.
Black holes radiate (sounds contradictory, doesn't it), and therefore lose energy (mass). There is some equilibrium size reached which balances this loss to mass inflow.
AFAIK, only really small black holes radiate enough to have a significant effect (and evaporate completely). I've not heard of an upper limit on the size of a black hole, and speculation is that the centers of galaxies are humongous black holes with the mass of large numbers of stars.
According to that scenario, our solar system could end up inside such a black hole eventually, as our orbit around the black hole at the core of our galaxy deteriorates...
I'm not really smart ('on par,' maybe), but I maybe can field this one.
Black holes, contrary to popular myth, actually do radiate. This involves virtual particle pairs and all sorts of crazy logic, and if you really want to read up on it you can email me for some accessible-to-the-layperson titles. Further, they don't attract matter to them anymore than a object of equal gravitational strength, so they aren't a universal vaccuum cleaner, more like a bottomless pit. So it's more of a passive "suck" then an active one, and you can orbit a black hole just like any other gravitational object of equal mass (rephrased, if you replaced the Earth with a black hole of equal mass, the moon and all the satellites would continue to orbit in exactly the same place they are now).
At any rate, black holes will only grow if they consume more matter than they radiate. As they radiate, the event horizon shrinks. So it's a sort of balancing act for the black hole. If the black hole doesn't balance it's consumption, it will either grow or shrink. If it's shrinking, it's mass - and therefore gravitational influence - dissipates, albeit slowly. Eventually, when it gets down to a critical size, it will explode in a burst of energy.
I have a theory. We're already being sucked into a massive black hole at the center of the universe. Due to time dilation effects, we don't notice this, but it does appear as if the rest of the universe is accelerating away from us. The wait for tech support doubles every 18 months... Any likelihood they can solve your problem halves. Foosters Law
Here's one to throw you for a loop. Straight from Cecil Adams' mouth:
Possibility number three (you may want to sit down for this) is as follows. For reasons that I confess are not entirely clear to me, when a black hole grows to enormous mass, it becomes less dense.
If our entire galaxy collapsed into an ebony aperture (I am getting tired of typing black hole), said BH would be about ten billion light years across, with the average density of a thin gas. If we take this to its logical conclusion, it is possible that the known universe is itself a black hole, with us living in it.
Wherefore, it seems to me, the obvious question is: how the hell do we get out of here? The casual attitude of our public officials toward this baleful possibility is nothing short of scandalous.
There are many different theories about it. The simple fact of the matter is that all the matter in the universe may eventually be concentrated within a single black hole, but it will take a few more years. The universe is still young. VERY young. The universe will be something along the lines of 10^70 years old before it gets swallowed up like this.
Another thing to realize, since empty space is more or less a sideeffect of the matter within it, if all matter is concentrated within a single singularity, there won't BE any space, and the universe will effectively disappear, at least back to the point it started at, a single point of high energy and mass, but no volume. BANG!
This, of course, relies on the theory that the universe is closed.
Well, increasing the escape velocity wouldn't do much. The event horizon is the point at which the escape velocity equals the speed of light, thus nothing can escape.
There are two theories on how the universe will end, depending on the amount of dark matter out there. If there's too much, what you mentioned will eventually happen. If there's not enough, the universe will just keep expanding until matter and energy are spread to far apart for anything interesting to happen. Cheers,
Rick Kirkland "Always remember you're unique, just like everyone else."
Wouldn't it make sense that, these black holes out there would eventually all converge together, gaining mass and 'size', presumably even increasing escape velocity?
The right answer is that space is almost empty, so the black hole cannot grow quickly. (but see below for more)
A black hole has the same gravitational pull as a star of the same mass would. So, if our Sun miraculously became a black hole, it could not suck in the Earth. Black holes are special because you can get really close to them. Since gravity decreases as the distance squared, small distance equals strong gravity.
Radiation is not a significant factor. Only very small black holes radiate significantly enough to matter. A solar-mass black hole would take 10^67 years to evaporate... alienmole had it right above.
In a high-density environment, black holes do grow. Namely, in the center of galaxies we see black holes that can be like a million or 10 million times the mass of the Sun. Ones which are actively feeding (on gas clouds, stars, etc) may explain quasars (the brightest sustained light sources in the universe).
The Milky Way almost certainly has a pretty decent sized black hole in the center, so our galaxy may once have hosted a quasar.
I'm Just to expound upon the point that we wouldn't get pulled in if our sun was a black hole.
Imagine the Earth and the sun as they are now. Then replace the sun with a blackhole (minus the whole supernova thing, though that wouldn't happen with our sun, which is why it won't become a blackhole). The gravitational pull would the the exact same on the Earth when it's orbiting the sun as a star, then it would be when it's orbiting a blackhole (life as we know it would die off without sunlight, but that's a different story). It's still the same amount of mass, it just has infinite density.
I liked some of the points made, but a couple of sentences sent chills up my spine:
Would that we could, but we can't, any more than you can make a black hole by shooting two billiard balls together.
this reminds me of the PATOS (PATEOS?) from Zodiac, as in: "by using a down-to-earth metaphor, we'll displace all your silly, uninformed fears"
From a theoretical viewpoint then, the risk of catastrophe is probably negligible.
I think it's the wording of this that gets me. "probably negligible"? I know I'll sleep well tonight because the PR flacks have told me not to worry about it.
bad news. i suspected this because that moody was imbecile. phew. life is boring. lousy pre-hegira time continues forever. better we all die. shrike i summon you.
Well... (Score:1) by Jizitup on Monday October 11, @05:13PM EDT (#61) (User Info)
Whoever said that if a black hole consumed the earth that we would be dead. Postulate please.
I could! imagine i could use science fiction movies as well as comedies (2001 and dr. strangelove)as sources as to why we should be worried about two sub-atomic particles creating a blackhole. I could further use Carl Sagan's musings on our own end due to nuclear war as fuel for the expirement killing us all. My source could be an obscure phyisist who quotes famous people like Stephen Hawking. Of course there would be no need for me to look into the specifics of these quotes after all they come from a wild eyed scientist (whos credientals are never mentioned). My final piece of news to freak out hte public to preform a witch hunt of these poor scientists lab would be to point out that we havent found life anywhere else so odds are, they were destroyed in thier own sub-atomic particle expirements gone wrong. That is journalism! Trust media, trust your TV. Dont think, TV cant lie. Just freak out.
Hmmmmmm ... (Score:0) by Anonymous Coward on Monday October 11, @05:20PM EDT (#65)
This article seems to contradict itself.
They dismiss any risk in this experiment by stating the fact that collisions in our upper atmosphere are often much more energetic than their collisions will be. They also point out that there are plenty of other accelerators in the world that produce higher energy collisions. Now, it seems to me that all of these collisions are of the same nature involving high energy particles. This experiment is uniquely different in that it is colliding heavy atoms of Au. What distinguishes this experiment from other accelerators and upper atmosphere collisions is the size of the collidees. To quote:
It is not a particularly energetic machine; indeed, the Tevatron at Fermilab, near Chicago, which has been collecting data for years, is much larger and more powerful. However, the Tevatron accelerates and collides single protons, whereas RHIC accelerates and collides gold nuclei containing almost 80 protons. This gives RHIC the potential to produce conditions of higher energy density and higher effective temperature than any other accelerator built to date ...
The key here semms to be that the collisions in this experiment have a very high energy density whereas the other collisions mentioned have a lower energy density. Presumably the collisions in the upper atmosphere, which they present as proof that our fears are unfounded, are also of the low energy density variety (I don't think too many Au atoms are colliding in our upper atmosphere). So are they not comparing apples to oranges? And if, as they state, this experiment is significantly different to those being conducted at the Tevatron, why is it not significantly different to upper atmosphere collisions?
"And if, as they state, this experiment is significantly different to those being conducted at the Tevatron, why is it not significantly different to upper atmosphere collisions?"
Because upper atmosphere collisions involve molecules such as ozone, oxygen and nitrogen rather than free nucleons.
Gold nuclei—what they're using, and what some people have said may be dangerous for the same reason you're saying#151;collisions happen on the moon all the time. They're pretty much recreating something that occurrs often, but in a way that they can observe it.
Eh, so what? (Score:2) by Tau Zero(spherethis@youknownottoincludethis.yahoo.com) on Monday October 11, @06:32PM EDT (#122) (User Info)
They dismiss any risk in this experiment by stating the fact that collisions in our upper atmosphere are often much more energetic than their collisions will be. They also point out that there are plenty of other accelerators in the world that produce higher energy collisions. Now, it seems to me that all of these collisions are of the same nature involving high energy particles. This experiment is uniquely different in that it is colliding heavy atoms of Au.
Except it's not uniquely different; this isn't so unusual in nature. If you scan old Scientific Americans for articles on cosmic rays, you'll find that some of them are almost certainly atomic nuclei, some of them heavy ones. They have been observed to strike Earth with orders of magnitude more energy than our puny efforts can achieve. And that's just what we've observed.
The Brookhaven effort has one thing going for it, and that is observability. The collisions will be nice and conveniently placed so we can analyze what's going on in them and get data; to get anything new about quark-gluon plasmas we're going to have to have detectors right on top of the action. If it weren't for that, we'd be far better off just watching what Nature throws at us for free. -- Deja Moo: The feeling that you've heard this bull before.
Anything that RHIC can do has already been done many times by Mother Nature without dire consequences.
To the best of my understanding, this statement is false. The RHIC is designed to recreate conditions that are not believed to have existed at any time since the big bang. So the RHIC may in fact do something that has only been done once before in the history of the universe. And if that event wasn't cataclysmic, I don't know what was!
I'm not suggesting that everyone should panic about RHIC, but trying to write it off as old hat isn't the appropriate response either.
To the best of my understanding, this statement is false.
No, it's true.
They are not claiming that these conditions haven't existed since the big bang. (That would be absurd.) This will simply be the first time such conditions have been recreated in a lab.
Please, reread the bit about cosmic rays. Every day the earth is bombarded by millions (I'm way underestimating here) of cosmic ray particles so energetic that they laugh heartily at the feeble attempts of Brookhaven to match them.
When we do it in a lab, we can be there to watch. But as far as the earth is concerned, it is very old hat indeed.
They are not claiming that these conditions haven't existed since the big bang. (That would be absurd.)
Why would it be absurd? Are you suggesting that it is impossible to recreate any of the conditions of the big bang, or that it is impossible for the conditions of the big bang to have not naturally recurred in the universe again since then? You wrote:
Please, reread the bit about cosmic rays. Every day the earth is bombarded by millions (I'm way underestimating here) of cosmic ray particles so energetic that they laugh heartily at the feeble attempts of Brookhaven to match them.
Irrelevant.
As far as whether the conditions the RHIC is intended to reproduce have existed after the big bang, I'd refer you to an authoritative source, the RHIC web site, which states:
While many RHIC collisions will produce interesting results, a rare few might create something even more special: a new form of matter.
Actually, it's not new to the universe, just to human eyes. It's thought to have existed ten millionths of a second after the Big Bang at the dawn of the Universe. It may also exist in the cores of very dense stars called neutron stars.
So what they are saying is that perhaps the conditions only existed at the big bang, or perhaps they also exist in neutron stars. What they are NOT saying is that the conditions naturally occur anywhere nearby.
You wrote:
When we do it in a lab, we can be there to watch. But as far as the earth is concerned, it is very old hat indeed.
As Arnold Rimmer would say: "Wrong, wrong, absolutely brimming over with wrongability."
Are you going to bother to say why cosmic radation is irrelevant?
This is from a New Scientist article on the exact same topic (which was much more informative, by the way):
In 1995, Paul Dixon, a psychologist at the University of Hawaii, picketed Fermilab in Illinois because he feared that its Tevatron collider might trigger a quantum vacuum collapse. Then again in 1998, on a late night talk radio show, he warned that the collider could "blow the Universe to smithereens".
But particle physicists have this covered. In 1983, Martin Rees of Cambridge University and Piet Hut of the Institute of Advanced Study, Princeton, pointed out that cosmic rays (high-energy charged particles such as protons) have been smashing into things in our cosmos for aeons. Many of these collisions release energies hundreds of millions of times higher than anything RHIC can muster--and yet no disastrous vacuum collapse has occurred. The Universe is still here.
This argument also squashes any fears about black holes or strange matter. If it were possible for an accelerator to create such a doomsday object, a cosmic ray would have done so long ago. "We are very grateful for cosmic rays," says Jaffe.
[emphasis mine]
For those who want to read the article, you can find it at http://www.newscientist.com/n s/19990828/ablackhole.html. Its a month or two old, but I think it's much more informative than the one linked here. It rebukes the Sky Is Falling cries with more examples than the one at the Boston Globe.
Before you call someone many different kinds of wrong, you may want to read up on it first. Our friend summed it up very well by saying it is "very old hat indeed."
Are you going to bother to say why cosmic radation is irrelevant?
Because I've seen no claims that cosmic radiation produces Quark-Gluon Plasma, the desired/expected result of the RHIC. The article you cite doesn't even make that claim.
No, because it doesn't need to. What is important in a High Energy Physics process is the collision energy. How you get to that energy doesn't matter (to first order) - you can collide light electrons against positrons (as at SLAC, where I work for example) or heavy nuclei together.
It is easier to get a higher energy with a heavier particle, since your relativistic energy comes in part from the mass of your collision particles. (But the collisions themselves are then messier, making detection more difficult). So, in short, we *have* (providing they exist) had Quark-Gluon plasmas formed in the upper atmosphere.
So why don't we do our experiments in the sky? Because with cosmic rays we have no control over the flux (number of particles per unit area) or energy, both of which we need in order to do detailed experiments. Cosmic rays are not without their uses however; with our detector, we use them to calibrate our systems before moving the detector to the "beam pipe", where collisions occur. This is standard practice.
So you're saying that it's impossible for a high-energy collision of gold nuclei (which I seriously doubt ever happens in the earth's atmosphere due to cosmic radiation) to produce different results than you get with smaller particles and higher energy?
If you can prove that, I suggest you publish a paper ASAP. I'm sure your Nobel prize will be waiting.
The total mass and energy out of the collision has to match what went in, but as I understand it, the specific details of what goes in have a significant effect on the statistical likelihood of the various possible results.
Yes, what goes in have a significant effect on the likelyhood. And iron is more likely to produce these effects. Collisions between iron nuclei is common enough that we shouldn't have had a snowballs chance in hell of still living if the problems had been anywhere near realistic.
Reread what you quoted... The quote contradicts your claims - not supports them.
They are saying that perhaps the matter created may be a type of matter that, quote is not new to the universe, just to human eyes, which directly support the claims of the post you replied to.
The quote then goes on to mention two conditions in which that kind of matter may exist or have existed. They do not state that it can't or don't exist other places as well.
Anything that RHIC can do has already been done many times by Mother Nature without dire consequences.
Fortunately, nature has been doing just these sorts of experiments planned at RHIC for a long time and the universe is just fine.
Umm... I'm sure the universe itself didn't suffer dire consequences, but then, what's another black hole to the universe?
I think the point is that while a black hole or two might not devistate the universe as a whole, it would be bad for any populated planets in the area.
W ------------------- This is my SIG. There are many like it, but this one is mine.
Art Bell guest (Score:0) by Anonymous Coward on Monday October 11, @05:24PM EDT (#67)
I don't care what that article says; this thing scares me a bit.
There was a very informative guest on Art Bell's radio programme the other night that had some troubling things to say about this. Apparently there is a lot more danger here than we are being led to believe.
I think that there are scientists out there who care more about these sorts of discoveries than their own lives. They would be willing to sacrifice themselves (and everyone with them) for this one presious bit of knowledge
Whenever you hear the name "Art Bell" connected with anything, you can be sure that what follows is content-free. Art Bell is the person who gives 'lunatic fringe' a bad name.
Sorry, but you've been had.
...phil "For a list of the ways which technology has failed to improve our quality of life, press 3."
Re:Art Bell guest (Score:0) by Anonymous Coward on Monday October 11, @05:54PM EDT (#94)
They would have to answer to God.
Re:Art Bell guest (Score:0) by Anonymous Coward on Monday October 11, @05:57PM EDT (#97)
There is no God asshole.
Re:Art Bell guest (Score:0) by Anonymous Coward on Monday October 11, @06:00PM EDT (#98)
Yes there is.
Re:Art Bell guest (Score:0) by Anonymous Coward on Monday October 11, @06:00PM EDT (#99)
No there isn't.
Re:Art Bell guest (Score:0) by Anonymous Coward on Monday October 11, @11:23PM EDT (#177)
if he doesn't believe in God then "see you in hell" means nothing dumbass
Re:Art Bell guest (Score:0) by Anonymous Coward on Tuesday October 12, @12:56PM EDT (#209)
We'll just see how much it doesn't mean, won't we?
Re:Art Bell guest (Score:0) by Anonymous Coward on Monday October 11, @07:06PM EDT (#134)
Nope, guess you'll have to explain it. Or not, who cares? At least *I* don't listen to Art Bell!
Re:Art Bell guest (Score:0) by Anonymous Coward on Monday October 11, @07:21PM EDT (#143)
In the documentary 'Contact', Jodie Foster plays the scientist who was willing to risk her life to discover the truth about extraterrestrial life. I've never been able to track down who the real scientist was however; it's uncredited. In this version of the story, comes back to testify in from the Congress; this didn't happend of course. She was never heard from again. While the true story was apparently not nearly as melodramatic as this depiction of it, it was very telling of how far some 'scientists' are willing to go to seek the Truth.
Documentary? You're kidding, right? That movie was based on a work of fiction, which was written by the late Carl Sagan, a scientist himself. He got a Nobel Prize for coming up with the nuclear winter theory.
First, Larry Niven wrote a cool Sci-Fi mystery story called 'Hole Man' which has a quantom sized black hole as possible murder weapon.
While most of the posts here have been silly, I would like to point out that as best I can remember, the pull (Gravity) of a black whole is still related to its mass. Read: Black hole's have infinite density, not infinite mass. So say you converted 1 gram of matter into a black hole, it still would only have 1 gram's worth of pull. So the world wouldn't just instantly get sucked into oblivion.
However, this tiny black hole would tend to fall, as all things near the Earth do, and it would consume any matter it came in contact with, namely the ground, the mantle, the core, bit by bit, an atom at a time. In fact the mass of the earth is so small that the size of the black whole, probably would never get big enough to consume more than an atom at a time. It could conceivebly consume the whole planet assuming it had a stable orbit, as this thing would orbit the the center of the Earth, while passing though the Earth. Now a stable orbit isn't likely to form from a black hole created in the described manner. So, when enough mass is accumulated, the elliptical orbit will toss this thing far enough into space that the Sun's gravity will get ahold of it. In which case it would begin eating the Sun, and anything else in its orbit. The same process would likely happen there, and eventually it would be tossed out of our solar system, to go eat Alpha Centari or something else. Of course it may just eat everything, but it would still take a while.
"Now a stable orbit isn't likely to form from a black hole created in the described manner. So, when enough mass is accumulated, the elliptical orbit will toss this thing far enough into space that the Sun's gravity will get ahold of it. In which case it would begin eating the Sun, and anything else in its orbit. The same process would likely happen there, and eventually it would be tossed out of our solar system, to go eat Alpha Centari or something else. Of course it may just eat everything, but it would still take a while." So what you're saying is, the black hole will eventually swallow up the earth and have the mass of the earth, and some previously unidentified force will mysteriously fling earth's mass from it's current orbit? This violates both conservation of momentum and conservation of energy. Even if a black hole did form, it would be as someone has already described: A black hole with the same mass and momentum as earth. So no consequences would extend beyond our planet.
"So what you're saying is, the black hole will eventually swallow up the earth and have the mass of the earth, and some previously unidentified force will mysteriously fling earth's mass from it's current orbit?"
Maybe, I was a bit unclear. It wouldn't consume the Earth unless it's orbit happened to be stable enough (by chance) as too not throw it out of Earth's orbit. In other words, it's elliptical orbit didn't through it so far away as to be captured by the Sun. I haven't thought about this all that much, but I suppose that the black hole would then assume Earth's orbit around the Sun. I'm making an assumption in this hypothesis, which I haven't tried to test (via math), that the hole's increasing mass will tend to give it an ever increasing elliptical orbit. Whose range would eventually exceed the radius of the Earth, and quite likely swing out past the gravitational equilibrium point between Earth and the Sun at some point, in which case the Sun's gravity would continue to pull it in towards it, or at least break it free from Earth's gravitational field.
"I'm making an assumption in this hypothesis, which I haven't tried to test (via math), that the hole's increasing mass will tend to give it an ever increasing elliptical orbit. Whose range would eventually exceed the radius of the Earth, and quite likely swing out past the gravitational equilibrium point between Earth and the Sun at some point"
But the sum of the momentum of the earth and the black hole must remain constant, so the black hole will actually slow down as it becomes more massive. Thus, if it isn't created moving at escape velocity, eventually we will wind up with a black hole with the same mass as earth in the same orbit around the sun.
"Now a stable orbit isn't likely to form from a black hole created in the described manner. So, when enough mass is accumulated, the elliptical orbit will toss this thing far enough into space that the Sun's gravity will get ahold of it. In which case it would begin eating the Sun, and anything else in its orbit. The same process would likely happen there, and eventually it would be tossed out of our solar system, to go eat Alpha Centari or something else. Of course it may just eat everything, but it would still take a while." So what you're saying is, the black hole will eventually swallow up the earth and have the mass of the earth, and some previously unidentified force will mysteriously fling earth's mass from its current orbit? This violates both conservation of momentum and conservation of energy. Even if a black hole did form, it would be as someone has already described: A black hole with the same mass and momentum as earth. So no consequences would extend beyond our planet.
Not only that, but in another short story of his (I forget the name) a man is killed due to the tidal forces of a stray black hole. The hole itself did not touch a single atom in his body, yet the gravitational forces it caused as it passed through his vital organs pulverized them.
Fred Moody is the mouth puppet for the Global Dominition Force who are paving the way for the Xian invasion. Stephen Reucroft and John Swain are paid apologists for the RHIC project but what they don't know is that RHIC is funded out of the CIA drug slush-fund by The World Government for the exact purposes of researching and developing a black hole doomsday device that can be used against the encroaching Xian fleet. We need these black holes to form a parabola shaped lattice that will be used as a net on the Xians. To spread the fear Fred Moody supports is basically yelling to the sky "I want a third arm so I can be a better worker in your intergalatic slave catering business!" We know RHIC will make black holes. We just don't know if it it will be enough. --Fjord
Debunking the fear (Score:3, Informative) by Anonymous Coward on Monday October 11, @05:33PM EDT (#75)
The opponents of this experiment were concerned about two separate issues:
The creation of runaway black holes. It is true, if you cram enough matter into a small enough volume, you may reach the density required to form a Schwarzchild-like (or, if you put some English on the particles, and some charge, Kerr-Newman) black hole. However, the Chicken Littles who worried so intensely about this phenonmenon failed to account for something simple: Hawking radiation, that is, black holes evaporate. The larger the black hole, the slower the evaporation, in contradiction to common sense. Little-bitty holes go "poof!" in a flash of radiation and heavy particles. Anyway, the aforementioned CLs (Chicken Littles) failed to do a calculation out of, say, _Black Holes: The Membrane Paradigm_, in the section under "Evaporation of Black Holes In A Thermal Bath." It's basic differential equations, not that bad. I haven't gone through them myself, but I don't exactly sweat the announced end of the world, either.
Strange matter. A very, very hypothetical possible byproduct (and from where they get the idea that it might be produced, I don't know) of certain collisions between selected particles would produce "strangelets," that is, baryonic matter like our nuclei, but with a non-zero strangeness (a quark property). Add hypothetical to hypothetical, strangelets can convert normal matter to strangelets and dump off energy. Again, the fear of a chain reaction. Once again, they overlooked the fact that strangelets only convert free neutrons. They can't even convert neutrons inside nuclei. Now, with a mean lifetime of approximately one thousand seconds, you just don't have a lot of free neutrons floating around. You'd have to work to create these hypothetical strangelets, hope that you'd get the conversion, and then build an entirely extra particle accelerator to funnel a beam of pure neutrons at your target. Not bloody likely.
Since most of the people doing the Chicken Little routine have doctorates, they should be ashamed. All of the data I have mentioned arises from my occasional prowls through the Web on odd topics and not much more than a light understanding of black holes. No good excuse exists for their collective oversight, and one might almost imagine that it is deliberate. "No such thing as bad publicity," goes the cliche, and I'm fairly sure that most of the remarks were made by second-raters with flagging careers who would like a little extra grant money.
You said: "...and then build an entirely extra particle accelerator to funnel a beam of pure neutrons at your target."
Correct me if I'm wrong, I'm not a particle physicist, but how would one accelerate neutrons? Electrons: No problem, positive things atrract them, negative things repulse them.
Protons: Again no problem, just the inverse.
Neutrons: Dang! How the heck do you grab one of these things, anyway?
I know how neutrons can be generated by a nuclear reaction, etc., but fail to see how you could ever beam-ize the little turkeys once you've made them...
If this is possible, I'd love to know how it's done. Given the unlikelihood of our entire universe existing at all, why is there something instead of nothing?
Can anyone explain what a strange matter reaction is, other than the fact that it involves the muon-family? -- "Western Civilization? That would be a good idea..." -- Mahatma Gandhi
As a Long Islander myself, and considering the mess over at Brookhaven (BNL), I'd just as soon they conducted their bangs elsewhere. Like out in the middle of the desert, where they won't fsck up our drinking water anymore with tritium and other )_#$...
Exactly what does tritium have to do with the collider?
-- I wonder if junk bots search for bolded REMOVE THIS or NO SPAM in addresses? (Obfuscated address a result of increased spam since open use on slashdot)
I'd advise you to go through your house and rid yourself of your smoke alarms for safety's sake. You know those things have radioactive materials inside them. Not only that, the radioisotope in there was manufactured inside a nuclear reactor! As you are no doubt aware, nuclear reactors are very very bad, as we found out this last week. Much worse then nuclear testing, which we seem to think is nice and safe since it's done in the desert. Oh, and on your way out, please be sure you avoid breaking any "Exit" signs--you'll release more tritium into your precious Long Island environment than the incident at Brookhaven.
(In all honesty, your drinking water is probably more messed up by industrial dumping over the years than it ever was from the Brookhaven Lab's modest program).
Actually, the biggest threat to the environment in that area is quite clear: it's the Long Island Expressway. The worst-case failure scenario at the High Flux Beam Reactor (the nuclear reactor at BNL that worries many residents so much) would increase the risk of cancer far less than the increment provided by the traffic on that one road.
I'm a Long Islander too and I've kept track of the weird media hype over here. Newsday with screaming headlines about "Radiation Hazard at Brookhaven!", etc. Remember the Shoreham nuclear power plant, hounded out of town? Well, the whole project was badly mismanaged by (the former) LILCO - though maybe not for the stockholders since they made out like bandits - but the reason the thing never opened (what was it, after spending $9 billion?) was not due to any rational decision making process, but a storm of hype about evacuation plans - my goodness, this whole island practically evacuates to Manhattan every morning between 7 and 9 am, it's not like we don't have enough roads and commuter railroads here. And it's a huge island to boot - it's not called "Long Island" for nothing. Plus being close to sea level and far from bedrock makes our natural radiation dose here about as low as you can get. The whole mess seems to be orchestrated by a bunch of Hollywood ninnies who happen to have their beautiful summer homes located in the nearby pristine Hamptons, and like to take on worthy causes like being anti-radiation or anti-whaling or something in their spare time.
The real problem with Long Island's ground water is overuse and sea water encroachment. This has made most of the water underneath Brooklyn and Queens unusable. Global warming will only make this worse - if a sea level rise doesn't wipe the island entirely off the maps... Luckily we do tend to get enormous quantities of rain throughout the year, keeping the water levels high. The high rainfall also helps quickly dilute most pollutants (including the tiny quantities of radioactive stuff BNL has released) so it's still pretty safe to drink.
He would LOVE this. Since his doomsday predictions have failed (consistant with all of his other predictions), he can now predict widespread economic collapse becuase of a black hole.
THE SKY IS FALLING, THE SKY IS FALLING !!!!!!!!!! THE SKY IS FALLING ...... that's what sells, isn't it?
Idiocies like this one come out into the open every few years. There is a problem with understanding probability and statistics which is not taught in general education but which is used by a lot of poorly educated journalists.
In somewhat the same style I cannot exclude with certainty that a brick cannot spontaneusly rise upwards due to the addition of brownian motion velocities of all particles in the brick. I can say that the probability of such event occuring is so small that one must wait longer than the age of universe for such event to occure, but that would be omitted in an ABC News article. ABC news is particularly infamous as science is concerned (and not just in physics). They promote pseudoscience and pure hockum and I am sure that they claim that its "the public right to know" that gives them the licence to be uneducated.
In this particular case, there is no well understood theory, so an honest scientific answer is of course that "we cannot be sure". However, these type of collisions of Earth matter with high energy cosmic rays happen quite frequently and we still exist. I am not a solipsist so on the basis of observation of my existance I can assure you that nothing will happen at Brookhaven except the frustration of quite a lot of people who will have to try and explain this to the money giving politicians (who are even less educated than journalists).
Question. (Score:0) by Anonymous Coward on Monday October 11, @05:50PM EDT (#90)
If this will cause the universe to reboot itself, will it be courteous enough to flash me a Blue Screen of Death(tm) first, staying 'Fatal Error - Press Ctrl-Alt-Del to reset'. If so, no biggie, I get it everyday. All is well...
"If this will cause the universe to reboot itself, will it be courteous enough to flash me a Blue Screen of Death(tm) first"
Quick! Let's all petition God (or whoever) to GPL the universe! Just because: 1) I don't remember agreeing to this in the license agreement, and 2) After 15 billion years, there's no way it's under any sort of warranty anymore. Think about it.
YES! Finally, an excuse to stop cleaning up those pesky Y2K issues! See you all later - I'm off on a spending spree - afterall, the world will end before the VISA bill is due!
Ok we can destroy the earth by blackholes or strangelets but what if we open up another dimension and all sorts of creatures crawl out?
But seriously, wasnt there some research recently about the probability and how the bell curve is wrong in certain situations meaning the less likely even is even more likely to happen then we used to think?
At least from what I could gather from the shape of it, that curve inicated that smaller events have more weight than "The Big One". If you were to go by that, it would be even less likely than by bell curve standards. Then again, I got a D in statistics (bad Quake 2!), so what do I know? "There are no truths, only opinions. Don't confuse the truth with you own."
Comfort (Score:1) by CiXeL on Monday October 11, @06:33PM EDT (#123) (User Info)
what does comfort be a bit about all this is how can we create a black hole if we havent even been able to ignite self-sustaining fusion in a lab?
Also although a bit off topic, how deep would the ocean have to be to fuse all the hydrogen into blackholes?
Re:Comfort (Score:1) by The Anti-Gates on Monday October 11, @07:19PM EDT (#141) (User Info)
About 2.5 times the mass of the Sun, if memory serves.
Fortunately, the Earth isn't dense enough for its gravity to smash the electron shells of the atoms at its core (unlike its larger neighbors, the Sun and Jupiter). Atoms at the Earth's core are only slightly more compressed than the ones at the surface, which means they're still basically empty space.A black hole of the mass we're postulating here couldn't possibly absorb enough mass in this environment to offset the virtual pair evaporation effect. Poof...no more black hole.
On a related note, if this experiment does produce a black hole (possibly), and it does evaporate (certainly), producing a flash of energy and heavy particles, will this be recorded on the scientists' instruments? And if so, will they publicize this? (Probably not...the mere _possibility_ that this experiment could produce a black hole has so many people in an uproar...imagine what the reaction will be if the scientists then say, 'Well, the experiment _did_ create a black hole...but it's nothing to worry about.'.
But enough about the hard science...we've all done the math (at least most of us have), and the the conclusion is obvious...we're not in danger of having a black hole eat the Earth (at least not from this experiment). What we _are_ in danger of is the hysteria that this Moody character is perpetuating. I particularly find this amusing in the context of the approaching Y2K debacle.
People have enough to be freaked-out about at this particular moment in history...there's no reason to throw gas on the fire.
Is it not the case that the "evaporation" of such black holes (while a solid hypothesis) is still considered to be just "speculation"? What if these black holes do NOT evaporate?
Just for fun, when the Fred Moody article came out, I calculated how long it would take a Brookhaven-style mini black hole to consume the Earth (calculations summarized here.
It takes about 10^59 years to consume one atom, let alone the whole Earth!
"So how many times does this black hole, with a cross section of (pi x RS2) hit something? It's about (column density) x (cross section) = (3.8 x 1033 cm^-2) x (3.0 x 10-98 cm-2) = once every 1.1 x 10-64 orbits.
Since each orbit takes about 20 minutes, this means the mini black hole suffers a collision every 3 x 1059 years" How can this be? I multiply 1.1e-64 orbits/collision by 20 min/orbit and get 2.2e-63 min/collision. This is 1.32e-61 s/collision, or roughly 10^61 collisions/sec. Assuming atoms are roughly an angstrom apart, this meand the singularity is travelling 10^51 m/s, or 3e42 times the speed of light. Please check your math!
>It's not my math that's in error. I simply misworded. You might also want to check your units. I noticed you were using cm^-2 instead of cm^2 for the cross-section.
Can you tell I sepent the last two semesters teaching chemistry lab? :-)
The (expected) size of space-time quanta would be 10^-33 cm > the estimated size of the black hole, which apparently suggest the necessity to take into account quantum gravity (not yet established, what a pitty!). How the black hole of such small mass (and size...) would form in the first place?
You need to take into account the energy introduced to the pair of gold atom nuclei by accelerator. The total collicion energy will be much larger than the rest mass of the nuclei. The original estimate is therefore inappropriate.
Nice END.. (Score:0) by Anonymous Coward on Monday October 11, @06:46PM EDT (#128)
I don't believe in those rumours of fatal experiment, but I think that if earth was sucked into an artificial black hole, it would be the best end for this world that I know :-)
Ok, so it's not going to rip a hole in reality and spawn all sorts of Star Trek-like anomalies that will swallow up the earth. Anyway, this link here has VA bragging that it got the contract to make the systems that'll collect all the data from it.
http://www.valinuxsystems.com/success/brookhaven.php3?session_hash=12450c79866ed3f2852f3a5 fdf070920 "There are no truths, only opinions. Don't confuse the truth with you own."
In the unlikely event that we are actually capable of sompressing atoms into such a small volume that we create a min-black hole, we have nothing to worry about.
A black hole created from the collision of such a small amount of matter would inevitably evaporate all or nearly all of its mass before it could be pulled into a region sufficiently dense to feed it mass faster that it was radiated. The mass of such a black hole may be estimated as the combined mass of the energies of the two colliding particles. Keeping in mind the upper limit given in the other posts, a (very small) upper limit for the mass of such a black hole may be estimated.
It wouldnt take too long for such a small mass to be accelerated toward the earth (using the good old trusty equation F=mA, but the hole would raditae its mass at an even more rapid rate--the rate of radiation is inversely proportional to the mass of the hole. Calculate it for yourself using the equations listed at the math link below. Although it is unknown what *actually* happens to a black hole in the process of dying by evaporation, it is not likely to be anything harmful (an explosion would be small due to the minute amount of mass involved and a stable micro-hole would be innocent).
Readers of scince Fiction might recall the micro-black holes in David Brin's Earth; it rurns out his physics was more or less correct.
In order to do anything really interesting and dazngeraous, wed have to collide even larger atoms at higher atoms, probably in large groups colliding at the center of a sphere and/or in an extremely dense medium. The we might have something to worry about (but not for very long....).
(for a brief discussion of the math behind hawking radiotion see http://www.alcyone.com/max/writing/essays/black-hole-evaporation.html; for simple discussion on the mechanism behind Black hole raditaion, see http://www.imsa.edu/edu/astro/astrostudents/97_98_1/t03p3/evaporation.html, and for a link to the article in which Hawking describes the discovery adn its implications see http://www.damtp.cam.ac.uk/user/hawking/lectures.html--not recommended unless you are bored or possess a more-than-casual interest)
Suppose that we are wise enough to learn and know and yet not wise enough to control our learning and knoweldge, so that we use it to destroy ourselves? Even if that is so, knowledge remains better than ignorance. It is better to know even if the knowledge endures only for the moment that comes before destruction than to gain eternal life at the price of a dull and swinish lack of comprehension of a universe that swirls unseen before us in all its wonder. That was the choice of Achilles, and it is mine, too. -Isaac Asimov
I wonder... (Score:0) by Anonymous Coward on Monday October 11, @07:40PM EDT (#148)
I wonder if it might be impossible to know the Grand Theory of Everything without destroying Everything first. Think about it: we may have to give up on physics one day simply because any further experimentation would create a black hole. The black hole might be God's guard dog. -Kevin
Then maybe we could market them as Black Hole in a Jar..but just remember you can toss those out a window by using a table leg. (wonder how many get that reference) or maybe a Sphere of Annihilation. (AD&D) Either way, a neat destructive toy that would get out of control.
Wasn't this a novel by David Brin, called "Earth"?
Also, it seems to me (and I am sure there must be some formula/theorm to back this up, something like Risk = Probability*Consequences ) that even if the probability is very, even *very*, small, if the consequence is infinite (such as the destruction of the planet), then the risk is infinite.
Cosm is a hard sci-fi story by Gregory Benford about a RHIC experiment that produces a macroscopic manifestation of the quark-gluon plasma (I won't say more -- read the book).
But basically, it's an entire book about exactly this issue. And much better done.
...the same paper that posted the story about the Israeli Quantum CodeWrecker PDA? Maybe the power source is going to be Strange Matter(tm) from New York...
...for all the naysayers and religious wackos (hey, not saying anything again religion, just the people who take it too far) to point to and say that Jesus is coming back, or the alien space ship is behind hale-bopp, or whatever the trend of the day is. Hate to say it, but I think that it is reactions like this that stand in the way of real scientific progress. You shouldn't be afraid of science, it is merely a way to learn and digest the information around us in a logical and common-sensical way.
Deitheres - Master of... er... something.
-- Child: Mommy, where do .sig files go when they die? Mother: HELL! Straight to hell! I've never been the same since. ICQ - 21302767
OK... this is a great example of a necessary debunking of sensationalist tripe. Perhaps it should be titled "Two Gold nuclei do not a black hole make." IMHO, this is obvious to anyone who has taken high-school physics. Does anyone know the email address of the person who wrote the stupid article? I'd like to ask him if he considered the ramifications of name-dropping Hawking into a piece of alarmist trash like that.
Honestly, some people have no decency. That the name of the finest theoretical physicist of our time should be attached to something like this is simply nauseating.
Even if this collider could create a small black hole it wouldn't be a problem.
All black holes undergo a quantum mechanical equivilant of evaporation. The smaller they are, the quicker they evaporate their contents into the visible universe as radiation. The basic idea behind the theory is quantum tunneling. If you compress something into a very very small volume, and as the volume approaches the Plank scale, the probability that particles trapped (in the classical sense) inside this volume can exist outside it will increase. This happens because the Debroglie wavelength of the particles doesn't change.
Now, in order to create a black hole with the small ammount of matter inside the collider, you would be looking at a Shwartzchild radius in the Plank scale. Somewhere in the order of 10^-30 m. (Maybe someone can check me on this with the approximation R=GM/c^2....this value may be too low).
Anyway, at this scale the black hole would vanish in an incredibly short period of time. Far too short to vacuum cleaner the Earth into a blackhole spacetime.
Large black holes on the other hand evaporate on scales greater than the age of the universe. Something on the order of > 10^100 years.
Bones, do you know what you've done ? Pretty soon they'll want a peice of OUR action !!! Star Trek, "A Peice of the Action"
There were problems with the original article, but is this one much better? Ignoring the general lack of scientific fact and huge helping of generalizations prevalent in this article (when did we get a G.U.T? Mr. Hawking will be so pleased!), the authors seem to think that since the universe is not likely to end, we here on earth will be AOK. Sure, things like this have been going on in the universe for millenia. Along with other things like novas, supernovas, and meteor impacts for example. None of these are going to occur in Long Island, but you have to admit things would be pretty uncomfortable for us if one happened here. But the universe would be "just fine" if one did. Unfortunately for the authors' argument, there are a lot of things that happen in the universe after which it is "just fine" that would leave us a long, long way from that state if it happened next door. And is the chance of anything occurring in an experimental science like this ever actually "zero" as they claim? This kind of generalization and platitude hurling worries me more than the original article ever could.
Segfault (Score:0, Offtopic) by Hard_Code on Monday October 11, @04:08PM EDT (#5) (User Info)
man, you can really tell segfaulters...
Re:Segfault (Score:0) by Anonymous Coward on Monday October 11, @04:22PM EDT (#21)
yeah, just look for natalie portman's.....
Re:First Post (Score:0) by Anonymous Coward on Monday October 11, @04:08PM EDT (#6)
Damn. So it be. Damn that posting delay. damn damn damn.
-- Child: Mommy, where do .sig files go when they die? Mother: HELL! Straight to hell! I've never been the same since. ICQ - 21302767
hey (Score:0) by Anonymous Coward on Thursday October 14, @01:46PM EDT (#229)
Hey wait a minute... why did you moderators moderate this so low? This guy is just trying to make a point about how stupid these first post kiddies look and you punish him/her for it? At least he had the decency to not post as an AC. I guess I'm not going to post anything controversial anymore when I'm logged in for fear of lowering my sacred karma.
Posted by Hemos on Monday October 11, @03:51PM EDT
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