Want to read Slashdot from your mobile device? Point it at m.slashdot.org and keep reading!


Forgot your password?
Trust the World's Fastest VPN with Your Internet Security & Freedom - A Lifetime Subscription of PureVPN at 88% off. Also, Slashdot's Facebook page has a chat bot now. Message it for stories and more. ×

Comment Re:Ray Kurzweil (Score 1) 84

All kinds of foods are fortified with all kinds of vitamins

The fact that a particular tofu manufacturer may fortify their product with B12 is only because they know that a lot of their market is vegan. Not all vegans eat tofu, or will pay attention to whether their brand does or does not fortify. Not all eat cereal either (the main "multivitamin-fortified" food that people consume), and a serving of a typical fortified cereal only provides about a quarter of your RDA anyway. Lots of other foods are fortified by specific nutrients, but rarely B12.

Comment Re:Strange (Score 1) 185

A person who doesn't even understand the concept of splitting up paragraphs is in no grounds for criticizing someone else as being "unintelligible". Likewise, starting off a debate by accusing the other side of "psychosis"... well, I'll not comment about what that says about you.

. 1. Your understanding of why water is required for LAWKI is wrong. It's principle properties (as far as LAWKI is concerned) are thought to be A. hydrogen bonding and B. solvency.

1) The presence of water inside a cell does not require that a wet external environment was the source of the hydrogen in said water.

2) There are countless solvents in the universe. Out of sheer coincidence over the past two days I've been reading papers on the solvency properties of ionic liquids and carbon disulfide (the latter being common naturally). The studied possibilities of cyanide chemistry on Titan use methane as a solvent. Ammonia is also common in the universe and is an excellent solvent. (if you want to argue against methane and ammonia because they're not polar, you're going to have to defend the concept that solvents must be polar - which in the studied case for Titan, they absolutely don't have to be in order to create some spectacularly complex cyanide chemistry). Carbon dioxide is a superb solvent in its supercritical state. There are lots and lots of common natural compounds that are excellent solvents in widely varying environments. Not environments that LAWKI would survive in, but that's because LAWKI is evolved to the conditions of Earth, utilizing molecules that are stable on Earth conditions for its life processes.

2. The Drake Equation. I'd speculate that if you sat down and studied the equation *critically*, that you'd see it has major flaws, the most serious (imho) is the assumption that each of its terms can be reduced to numerical values and that each term is independent of the others.

Which can be resolved by combining terms. Feel free to present your alternative (many people have); each form nonetheless invariably projects massive numbers of civilizations.

3. The Fermi Paradox also has serious problems. Let's say that interstellar travel is technically impossible

A premise I'll gladly accept.

- that there's no propulsion technology which can transport viable (sufficiently complex) intelligent life across interstellar distances. Then there is no "paradox"

Except that there still is, because even if a civilization evolved only 1% earlier than ours did (a very tiny margin!), it's 138 million years old, and can thus be expected to have been long moving out at relativistic speeds in all directions. The Milky Way's diameter is only 100-180k light years. Even Andromeda is only 2,5 million light years away. Even civilizations having advanced to the point of interstellar travel just a mere 1% earlier than we've reached our current state should be arriving from all over the local group - let alone ones that developed 5%, 15%, 50%, etc earlier. The fact that life tends to spring up wherever there's water is not consistent with the observed emptiness of the universe.

Cosmological distances help keep is apart, but it is also a requirement that life be very rare.

Another problem can be seen if I use the same reasoning to claim that every square meter of the Earth's surface must have been "visited"

The more appropriate comparison, since we're talking about beings that reproduce, and over timescales representing countless generations, is to claim that every square meter of Earth's surface must have been visited by bacteria. And golly gee, it has. Even ignoring the point that bacteria don't have intelligence to guide them.

Finally, you should account for the stupidity of any group of fans of any meme. The *experts* (hopefully, the people who have enough of a background and have carefully thought about the problem of detecting extraterrestrial life, which would include careful and thorough study of the scientific literature) would, I believe, strongly disagree with your assertion that they claim water = life.

There is no broad agreement among scientists about the topic. So your trying to assert that "experts think X" is simply wrong, for whatever value of X you wish to choose. There are some scientists who are very keen on the concept of life being found wherever there's water, and just as many opposed.

LAWKI requires the presence of liquid water

More specifically, LAWKI has evolved to require the presence of liquid water. We know absolutely nothing about what form it was when it began.

Liquid water doesn't require the presence of life.

Tell that to the large numbers of scientists working at NASA who assert otherwise. They've even used "follow the water" as the official name of several campaigns' search for life on other planets. The "follow the water" concept is that wherever water has existed in the liquid state, life is likely to arise. This is a concept I am very much against.

There's so little we know about abiogenesis, that talking about it is practically useless

Exactly my point. Yet so many people - and I'm not entirely sure whether you're among them - keep acting as if LAWKI in its current state must inherently represent the same sort of biological processes as in its earliest state, with the same sort of needs. And the "follow the water" crowd further asserts that wherever water exists, life is likely to arise - as if we have any bloody clue about what conditions led to the first successful hypercycles on Earth.

I note that while I hold out some hope we will discover planets in our local neighborhood (say 500 light years from Earth) which have spectroscopic indications that life might exist, it is almost certain that there is no way for life to be detected at "cosmological" distances

I was very clearly and explicitly referring to other species engaging in interstellar travel. Something that's pretty much a given for any species that's been around even a fraction of a percent longer than we have. How you interpreted the term "encountering" as "detecting" is beyond me.

Another obvious "solution" to the Fermi Paradox, is that IF intelligence must evolve in social emotional animals, then it will inevitably produce a species which will cause it's own extinction

Extinction becomes difficult once you become a multiplanetary species, and almost impossible once you become an interstellar species. Some, some may well find a way to kill all of themselves before reaching that point (although total extinction is a tall order). But if you're in the "follow the water" crowd there should be life evolving at almost every star, often multiple planets per star. Unless you're talking a probability of extinction on the order of 99,99999999999999999999999%, that explanation doesn't cut it.

The assumption that intelligence is a benefit for the long-term survival (say on scales of hundreds of thousands to millions of years) has exactly zero evidence to support it. If it were such a great thing, it would probably already have developed *here* and we'd be covered in scales (or have 6 legs).

I can't even make out what you're trying to argue. Intelligence did evolve here. On many different lines (birds are quite intelligent, cephlapods, other mammals, etc).

If by intelligence you mean sentience, it did evolve here too. Are you trying to assert that it should have evolved instantly with the first life? Since when does evolution work that way?

Comment Re:Ray Kurzweil (Score 5, Interesting) 84

Funny, the only schizophrenic I've ever known was also vegan.

I'm a vegetarian, and have strong sympathy for the motives behind being vegan. But take your B-12, my vegan friends. Unless you eat large amounts of soil, feces, or bacterial concentrates, or you've had a rumen implanted in your body, you need it. Higher plants don't make it. Every "vegetarian" mammal has to get it from somewhere, and those not lucky enough to have rumens (or other organs filling equivalent "cultivate lots of bacteria" roles) either get it through eating soil, feces, insects (accidentally or on purpose), or other such sources. Even our "strict" vegetarian gorilla relatives eat grubs. Heck, even though I consume dairy, I still take a B-12 supplement, just to ensure that I get enough.

Also, B-12 shortage doesn't hit you immediately. The body stores about 5 years of B-12. So it'll catch up with you sooner or later.

Comment Re:Bastard (Score 1) 225

When I heard Musk was getting into boring, my mind immediately jumped to: rocket engines. Either to throw abrasives or for simple thermal spall.

If you want to channel a lot of energy in a short period of time at a surface, you can't beat a rocket. Now, getting it to do what you want, and not destroy your hardware, that's the challenge... ;)

Comment Re:Strange (Score 1) 185

As for the issue of what we should be looking for, it's hypercycles. Complex interactions of chemicals being driven by an energy source, cycles which might have the potential to "close the loop" and catalyze their own creation. And in that regard, I'd argue that Titan is a more likely place for life than Mars (although I don't expect to find life there, either - but what you can learn from studying the chemistry has so far proven to be fascinating, there's apparently a whole range of cyanide compounds at Titan surface temperatures that can perform the basic steps of all major life processes - even photosynthesis - and in some cases even more effectively than LAWKI can in Earth conditions).

I'd also argue for looking for phenomena that are difficult to explain by other means. For example, some people have pushed the "Martian methane" thing, but that's not particularly compelling, it just means that Mars isn't entirely geologically dead. I've heard a similar non-compelling argument for OCS on Venus. Of the "unknowns" in our solar system, I again think Titan has presented the best case to date, in the fact that multiple lines of evidence show higher hydrocarbons apparently disappearing at the surface, and some evidence (less clear) suggests hydrogen also disappearing at the surface. The this sort of metabolism of theoretical life on Titan - decomposition of higher hydrocarbons with hydrogen - was theorized before the above data was discovered (published right as Huygens was landing, actually). And that's something very difficult to explain by natural reactions at Titan surface temperatures - discovery of a natural catalyst that could do that would itself be an incredible find. There are argued non-life explanations (some sort of method that sequesters higher hydrocarbons underground where we wouldn't detect them - they're not dissolved in the seas, at least, which appear to be pure methane), and due to the Fermi Paradox I expect explanations involving non-life answers to be the correct ones. But, to me at least, Titan certainly seems more compelling than Mars and its destroy-organics-on-contact regolith.

And don't get me wrong, I absolutely want to see what's under the ice in Europa or Enceladus. But I don't expect to see anything swimming. Enceladus appears to have a soda ocean (Mono Lake-style), and I wouldn't be surprised if Europa's is similar. Dead, but potentially with interesting chemical clues.

Comment Re:Strange (Score 1) 185

That's just the point (although not exactly correct, H2 is the most abundant compound in the universe, and carbon monoxide is second... but still very abundant). The concepts of "life occurring wherever there's water", "water being everywhere", and the Fermi Paradox do not play well together. If life occurs wherever there's water then there should be millions of pan-galactic civilizations in the Milky Way. The very point that water is so abundant strongly argues against the "follow the water" hypothesis.

And I'll repeat my point, since you apparently missed it (with your "already know works great") remark: the fact that LAWKI "works great" with water is practically a truism, because water is by far the easiest source of hydrogen to come by on Earth, and LAWKI is built on CHONPS. Even LAWKI (let alone whatever other potential kinds might exist) can already deal with all sorts of other hydrogen-bearing molecules found in the universe, such as CH4, H2S, and NH3. And this on a world where those things are not common at the surface.

The argument that life depends on water because on Earth we find life wherever we find water is like an anthropologist in ancient China saying that human life depends on rice, because wherever rice can grow, you find people, and human civilization is adapted around the cultivation of rice. It misses the point that rice is just one potential source of the nutrients that humans need, and that their civilization adapted to the cultivation of rice, rather than there being some simple A=B relationship between humanity and rice cultivation.

But this all misses a more important point, in that the question is not about what "highly evolved life can use to live and reproduce". The actual issue is about what conditions are required for abiogenesis. And we have absolutely no clue about that whatsoever - just widely divergent hypotheses. What we can say is that when it happened on Earth, Earth was a very different place, and whatever sort of peculiar environment set it off is almost certainly long gone. And not knowing what that environment was, we have no ability whatsoever to say how common it is - except to point to the Fermi Paradox and say "probably not bloody common at all".

Comment Re:Strange (Score 2) 185

According to what studies specifically? The Drake Equation and Fermi Paradox are not fast friends. The former insists there should be life. The latter says we should already have seen it. Many attempts have been made to explain the latter in a way that doesn't contradict the former. We really don't know what the right answer is.

Honestly, I'm very much in opposition to the "follow the water" people. The argument goes, "everywhere that we find liquid water on Earth, we find life - so we just need to find liquid water elsewhere, and we should find life". Which I find to be patently absurd. It's a truism that anything life is made of, it has to be able to get, in some sort of reactive form. On Earth, water pretty much has to be the source for hydrogen, and hydrogen is one of the elements that make up all LAWKI (that is, CHONPS). That says absolutely nothing about whether water must be the source of hydrogen, or whether forms of life that don't use hydrogen are possible. It just says that life on Earth is well adapted to build itself out of the elements found on Earth. Well, duh, that's going to happen by definition.

The other related argument is that life appeared on Earth shortly after the planet cooled, so not only should life form wherever there is water, but it should do so quickly. You know, as if the seas as a whole simultaneously and spontaneously evolved life proto-cells across their breadth, rather than there existing some particular isolated location that happened to have the right conditions for life, which seems vastly more likely, and which the vast majority of abiogenesis theories call for. We do not know what that situation was, and can only speculate on it. But assuming that wherever you have liquid water you're going to have paired with it such a situation is such a huge unsupported leap of logic. And one thing we can say for certain about Earth's early seas is that they were nothing like today's; they were bright green, full of unreduced iron. Earth was a dramatically different place then.

Water is bloody everywhere in the universe. Liquid water not that much rarer. If you accept the "follow the water" peoples' ideas, than life should exist in almost every solar system, and on the surface in a good number. That's just turning the dial on the Drake Equation up to 11, and consequently, doing the same with the Fermi Paradox. Fermi Paradox solutions like "life evolving toward intelligence is rare" flies flat in the face of evolution, and "intelligence reaching sentience is rare" is way too much human hubris, insisting on some sort of magical Rubicon-crossing intelligence jump that sets us apart from other animals. In reality our problem-solving ability isn't so vastly greater than our nearest relatives; the main Rubicon that we've leaped across, the one thing that we do vastly better than our relatives, is communication - the ability to convey ideas to our fellow humans. And "communication" hardly seems like some sort of unevolvable barrier.

It seems much more likely to me that the answer to the Fermi Paradox is just that life is not a common occurrence, not something that just spontaneously and quickly generates wherever you have water; that life is rare, rare enough that cosmological distances keep us from encountering each other.

I'd also like to add that I think the chance of planetwide extinctions (especially before life is really tuned) is perhaps underrated. The more we learn of our neighbors - even here in our middle-of-nowhere location around our relatively tame star - the more we learn that they haven't always been as they are now. Venus, for example, appears to have once had seas of comparable scale to Earth. If the "follow the water" people are right, then life should have evolved there. But of course Venus hardly resembles Earth at all day. It's not even just the issue that Venus has lost the vast majority of its water; Venus's entire crust (with the possibility of some small exceptions) was resurfaced around 500Mya. Can planets just up and do that? Some models show that the planet's atmosphere sometimes condenses out into a supercritical foam, too. Pluto experiences something similar - sometimes its pressure appears to be vastly higher, forming rivers of liquid nitrogen, carbon monoxide and methane that have carved the landscape. The more we learn about Mars, the more we find that it, too, used to be a vastly different place; rather than a surface packed with sterilizing perchlorates and hexavalent chromium, it used to be dominated by acid-rich seas. So I wouldn't underestimate how fortunate we are in having a planet that's proven to be "relatively" stable - the occasional giant asteroid impact, volcanic trap, or superfreeze notwithstanding. There's absolutely no reason to think that Earth is "typical".

But hey, just my view. People will differ :)

Comment Re:SIR winston churchill ! (Score 4, Interesting) 185

If you were writing that hundreds of years ago, that's be a perfectly normal statement. Queen comes from Old English cwen (queen, woman, wife) - having originally been in the context of "wife (of a king)", and only later to refer only specifically to royals. It stems from the proto-germanic kwoeniz (wife), from PIE gwen (woman, wife), cognate of Greek gyne (woman, wife), Gaelic bean (woman), Sanskrit janis (woman), etc.

Lots of words related to women have changed over time, it's sort of weird. In Middle and Old English, woman was wif, which later became wife; the word "woman" comes from "wifman", or "woman-man", in the context of the gender-neutral usage of man that's been steadily dropped from English over the past half century (aka, more like "woman-person"). Wif still exists in English in a context closer to its original meaning in the word "midwife" - "woman who is with" (mid being a cognate of the Old Norse miðr (with), seen today in languages like Icelandic "með", Danish "med", etc)

Even "girl" has changed. "Gyrle" used to refer to babies only (more commonly female, but of either sex). Boys were "knave gyrles" and girls were "gay gyrles" (yeah, the latter term has changed a bit ;) ). The word "boy" existed at the time, but more often referred to a servant or commoner rather than being a generic term for "young male".

Comment Re:Ahead of his time (Score 4) 185

Yes, but nuclear weapons were not. Don't get me wrong, people were speculating about harnessing the energy of the atom for weapons. H. G. Wells coined the term "atomic bomb" in 1914 in "The World Set Free", but they were like ordinary bombs that continued exploding for days. Heinlein wrote about the development of a nuclear weapon to end World War II 1940 ("Solution Unsatisfactory"), but it was about a dirty bomb. If you have anything from before 1925(*) that's so accurate of a description of what nuclear weapons actually were, I'd like to see it. He got the minimum size wrong, but apart from that, that's pretty prophetic.

(*) - That quote was published in 1929 and written in 1925.

BTW, the autopilot invented in 1914 was just a self-leveling system with a compass - it wouldn't be anywhere near accurate enough for guiding flying weapons. Flying weapons "by wireless or other rays", aka remote controlled (passive or active) aircraft is an entirely different thing. Something that actually was done in World War II, but a decade and a half after Churchill wrote that.

This doesn't make him some sort of Nostradamus, but it does mean that he was paying close attention to the technological developments of his time and thinking over their implications with an analytic mind.

Slashdot Top Deals

"Dump the condiments. If we are to be eaten, we don't need to taste good." -- "Visionaries" cartoon