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Comment An intelligent enemy might do it (Score 1) 349

If "extinction" is the level of catastrophe we're looking at, then most of these events won't meet that high a bar.

I mean, even after a major asteroid impact or even all out nuclear war there are going to be some survivors; maybe in unlikely places (nuclear submarines*, the ISS, Iceland, Antarctica). Likewise, almost every "natural" pathogen will leave resistant survivors even if there is no vaccine or cure. As long as enough are left to breed they could restart humankind (but perhaps at a very reduced level of technology/civilization). Whether or not they would ever be able to recover to our current state due to exhaustion of most easily exploited resources is another question but forever is a long time. If there are a sufficient number of survivors and IF there is a repository of knowledge that has survived (archived wikipedia perhaps?) it is probable that decades or centuries of technological development can be skipped (like going directly from wood burning furnaces to photovoltaics or wind power).

However, if there is an Intelligent enemy that is pursuing us, then our chances are much lower. A sentient A.I. that wanted to wipe out humanity could track down and eliminate those in shelter or get them when they come back out of hiding. I guess the long-living product of an intelligent enemy (like mindless "grey-goo" nanobots) could do the same thing by continuously and systematically breaking down the biosphere (and anything that re-enters it from space, the deep ocean or the polar regions). Then, unless we've recreated another biosphere somewhere else (is that why you're going to Mars, Elon Musk?) we're all dead. Of course, WE are our own intelligent enemy and a deliberate attempt to wipe ourselves out (super weapons, resilient viruses) or even big "oops!" ("gene-drive", mini-black holes, large asteroid mining near earth gone wrong), might readily succeed.

We have met the enemy and it is us.

*Okay I know that the crews of nuclear submarine are (nearly?) all men. But if there are any women left at least they'll have a good gene pool to dip from!

Comment Put the Beamer array on the FAR side of the moon (Score 1) 381

Since there are so many parts to this project that are on the thin line between science fiction and science fantasy I think their estimate of 20(?) years (or about one generation) of development is more than a little optimistic. That said, in TWO generations this kind of thing might be a bit more practical, especially if, by that time, we have some relatively robust nano-bots that could construct and MAINTAIN the "starwisp". (Their stated approach to getting over the very probable impact of interstellar dust at relativistic speed is just numbers; that is launch a lot and hope a few survive. Not a very solid strategy to hang a likely multi billion dollar project on).
Given that time frame (around 50 years?) another possibility arises. Their proposal currently has the 100 GW laser Beamer array being in a high altitude part of the super-dry atacama desert in Chile. Despite it's deliberate isolation from major population centers, it could still be used as an insanely powerful anti-sat weapon which would essentially give the controlling nation the power (ha ha) to rule near earth space. (Current technology shows 100KW lasers blowing drones out of the sky, this would be a million times more powerful). Even though it only can "see" half the sky, almost all orbits would eventually process overhead, only get-sync satellites on the opposite side of the earth would be permanently safe. This potential destructive capability would probably be a major block for international approval of this project.
So, since the insanely ambitious other aspects of this project are unlikely to be ready soon, why not plan for a time when (hopefully) launch costs have given us ready access to the moon? In fifty years, it probably won't be insanely expensive to build this array on the Far side of the moon and it brings several advantages. No atmospheric distortion, geologic stability, slow (two week pointing time) rotation and abundant solar power just adds to the principal advantage of being unable to be used against the earth (and near earth objects possibly out to the moon's orbit). Another major advantage is that with the improved stability and beam purity it may be possible to keep it "locked on" for farther than 1 million kilometers. If it could do ten times this distance then the acceleration could be reduced and, more importantly, the sail would only have to be not absorb 99.9 % of the radiation instead of 99.99%. (Or the payload could be increased by a factor of ten or, you get the picture).
For these reasons, a far side lunar array should be considered. As an aside, in addition to using this laser launch system to power space vehicles/habitats throughout the solar system; it might prove to be a very effective asteroid deflection system. A 100 GW laser beam hitting the side of an asteroid would provide a very powerful "kick" from the presumed boiling off of any material there. Over long periods of time, perhaps even the light pressure alone would be significant.

Comment Can it be mated to the Falcon 9X? (Score 2) 57

If the cargo version of the Dream Chaser (which I note is also winged and reusable), can be launched on the Falcon 9X (I think this is the version that has the reusable first stage) then almost the entire vehicle is reusable!

I think it will, unfortunately, still require a (small?) second stage to get it into orbit but perhaps the Dream Chaser (cargo version) can boost itself into orbit. In any case it would provide another reusable re-entry option for the Falcon (the Dragon space capsule of course has been proven to be recoverable).

Interesting to note that the wings on the Dream Chaser are folding so it can fit inside a launch fairing. Is this the normal launch profile? Does it never launch "naked" with wings unfolded? Perhaps the aerodynamics are just too problematic for a winged vehicle on the tip of a booster stack. Maybe that's why the crewed version didn't get approved (it would not be good to have the crew inside a launch fairing in case of an accident).

Comment Actually they're decelerating towards us (Score 4, Interesting) 133

The aliens have their drive unit pointed at us as they want to decelerate into our solar system and not fly right through it. Their drive emissions are tremendously blue shifted (into the gamma rays) since they are approaching at a fair percentage of the speed of light (and maybe the drive is outputting gamma rays to begin with).

The best way to verify this would be to look at the spectra of the gamma ray emissions and see if they are gradually being redshifted (slowing down). This would give us an idea of how fast they are decelerating and maybe when they will be arriving. Let's hope that their ship isn't really huge or that it's not pointed directly at us so that their drive won't scour away our atmosphere!

(They could also be using a huge solar sail and what we're seeing is the reflection of our own sun but they'd really have to be moving very very close to c in order for it to be reflected as gamma rays. In that case, since they would be traveling just behind the wavefront they would also have to be right on top of us!).

Comment How bad is piracy on Android? (Score 2) 166

I live in Vietnam so everything here is pirated already. How bad is it in the U.S. (and other "developed") countries? Are most apps available (illegally) for free?

Maybe even if they are "pirated" they can still earn revenue for their developers if they earn money through ads. Or have the pirated versions been modified to remove/change the ads?

Comment Use the water to move the asteroid (Score 1) 37

So, once they bag and bake the asteroid to get the water out of it, why don't they use the solar collector to heat the water to make super (super!) heated steam. This can then be directed to propel the asteroid in the opposite direction. I believe a similar scheme has been proposed on earth to make laser (which are based on the ground) launched rockets using water as the working medium. If the water can't be heated enough to get a fast jet, you could always electrolyze it and just combust the oxygen and hydrogen like a normal chemical rocket.

I presume this scheme only is practical for small asteroids ( 100m?) because the "bag" must be big enough to fully enclose it. Otherwise it might be practical to use it for asteroid (self) deflection. Still, if there are a lot of these smaller asteroids available and if they are pretty "waterlogged" maybe this technique could be compared to almost having fuel tanks scattered around the outer solar system. A small spacecraft could approach one, wrap it, and then use the asteroid "jet" to scoot around the solar system. (As I mentioned by using the term "waterlogged" hopefully most of the asteroid is actually water, this would mean it wouldn't have to move around so much dead weight).

Comment Think he deserves an apology? Make it so! (Score 2) 113

After reading the article on the NYTimes, I went to and made a petition to:

"Apologize to Dr. Xi of Temple Univ. for the FBI's wrongful accusation and prosecution of him on charges of spying."

The complete text reads:

After reading this article in the New York Times:
I was appalled and upset that another Chinese-American citizen had been wrongly accused and prosecuted for spying when even a basic check could have exonerated him. That this even got to this point not only speaks to the incompetence of the FBI but a pervasive bias and distrust of Chinese American CITIZENS.

President Obama should, at the very least, on behalf of the U.S. Govt. apologize to this distinguished professor who has seen his reputation shattered and loss of various posts and titles. This will be an important symbolic act.

If you believe that he (at least) deserves an apology, follow this link and "sign" the petition:
For those of you unfamiliar with how this works, once it reaches 150 "signatures" then it is publicly viewable. If it then reaches 150,000 within a month then the white house promises to respond.

Please note: when I mentioned "another Chinese American" I did not mean that I am a Chinese American. I am not. Rather I was talking about the other Chinese American CITIZENS (like Wen Ho Lee) who have been charged and prosecuted apparently for no other reason than they are of Chinese origin. They were found innocent.

Comment Re:Problems in Vietnam, have I been hacked? (Score 1) 66

Yeah, I got fiber from Viettel, it's supposed to be 38Mb/sec but you really only see that at night when network congestion is low. I think the bottleneck is the few (two?) international fiber links that connect Vietnam to the outside world and that have very frequently(!!!) been cut. They've been cut so often and (almost always?) in the spot that only affects Vietnam's traffic that I suspect that China has a hand in it. (I'm assuming that China might have some deep sea technology that no other nation in the South China sea has).

Comment Problems in Vietnam, have I been hacked? (Score 3, Interesting) 66

Now that might explain some recent strange network problems that I've been having here in Vietnam. About 3 weeks ago, Google started denying my searches saying that due to the large number of attacks coming from your network they would refusing traffic (or something like that). I immediately checked my home network (a fiber optic TOTOlink router) and changed the password but the messages persisted. (They're gone now.)

I thought that perhaps I had a (lot of) neighbors who had been compromised/involved in attacks and perhaps Google was casting a wide net (blocking a large subnet of the ISP or even the entire ISP) and that I was just caught up in it. That may be the case, like the summary says there are few ISPs and presumably few different routers being used so it would be easy for a hacker to exploit a vulnerability and command a botnet of thousands of routers. On the other hand, I looked up TOTOlink router vulnerabilities and it said that there is an unpatched backdoor to my model so it is vulnerable. I assume this is true even if I changed my passwords.

So (since I'm obviously not an expert) my question is: is it likely that my router has been hacked? Will it allow the hacker to use it as a "bot"? Is my (unencrypted) traffic vulnerable to interception/change/man-in-the-middle attacks? Or is it more likely that Google isn't blocking my little network (that is attached to the internet by a single dynamic IP address) specifically but is blocking a large portion or even the entire ISP (in my case Viettel?).

I hope whoever can answer my questions is rewarded Karmically! Thanks! :)

Comment unfortunately pretty unrealistic... (Score 4, Informative) 99

"carbon nanotube tether anywhere between 62 and 620 miles long attached to a diamond-tipped harpoon"

Considering that the few attempts at space "tethers" have (I think) ended in failure and their cable lengths were much shorter, I think it is highly unlikely that they'll be able to make this work. They've also got to be able to "shoot" the harpoon at at spot on an asteroid that is neither too hard so that it'll bounce off of shatter the harpoon or so soft that the harpoon cannot have purchase. Of course, this is only worthwhile if the spacecraft and asteroid are traveling at a high velocity relative to each other. That way the spacecraft will either get a big savings in energy because it can use the tether to slow it down relative to the asteroid (and potentially generate a ton of energy through resistive braking!) or it could use it to "swing" around and dramatically change its direction of travel (like a gravity assist but with much more latitude). So the harpoon would be hitting the asteroid at kilometers per second and would need to "stick". (A mechanism to cut the cable or release the harpoon might be necessary if this system is to be used more than once).

As long as we are using carbon nanotubes and diamonds perhaps we should use a large lasso instead with micro thrusters positioning it for optimal placement. In any case IF this system could work then, yes, the spacecraft could go swinging through the solar systems using asteroids (small bodies with no atmosphere and little gravity) like Tarzan uses vines hanging from trees. I fear that the engineering difficulties are so great and the risk (you probably only get one "shot" during a flyby) will make this impractical.

Side note: - This idea is related to my, ahem, own idea of using a spacecraft that lands on an rotating asteroid, and then, using a tether, slinging off pieces of the asteroid into space. This could allow a very modestly sized spacecraft to divert the trajectory of an asteroid because it would be harnessing the energy of the asteroids rotation and converting it into kinetic energy. By landing (gently, no harpoon necessary) onto the asteroid's equator and extending a tether beyond the asteroids "geosync" orbit it could keep it permanently taut using a counterweight. Then, just like a space elevator, it would ferry material up to and beyond the geosync point, generating energy (to power the elevator) beyond that point using resistive braking before it flings the material into deep space. Properly timed releases could impart a directional thrust to the entire system. (If the asteroid is rotating fast enough the system is small enough that carbon nanotubes wouldn't be needed.)

Comment Use RTGs for ion propulsion then comm. (Score 3, Interesting) 77

NASA's needs Pu to get to Uranus (puns intended). If they can manage to get the correct isotope of Plutonium then a space probe that uses ion propulsion would have the necessary electrical power to drive the extremely efficient drive even when, as in this case, it is very far from the sun. Since the space probe DAWN has proven that multi-year thrusting of ion engines does work quite well, this would enable a "flagship" (read "big") mission to get to the very outer planets in less than a decade. It could spend roughly half its time accelerating to a high cruising speed then almost as long decelerating to be captured into orbit.

Then, once the mothership has arrived in orbit then, like Cassini, smaller spacecraft could be employed to explore the various moons and atmosphere of these gas giants. (Unfortunately since the moons of Uranus and Neptune may not be large enough to effectively permit gravity assists like Cassini uses with Titan or Galileo used with the four large Galilean moons, you might need smaller probes because the ion drive may have too low a thrust for dynamic orbital changes). Now the RTGs, having powered the spacecraft to the far reaches of the solar system, could be "gainfully" (ha ha) employed to power a high bandwidth radio transmitter/laser communicator. This would enable the small probes exploring the system to send lots of data back to earth without each carrying a huge antenna, only the mothership.

Why all spacecraft don't utilize the extremely high energy/weight RTGs for deep space PROPULSION is beyond me. I (maybe mistakenly?) think that the RTGs, since it generates its power from the natural decay of a radioactive element, is constantly "on" and if you don't use the power being generated YOU LOSE IT (anyone please correct me if I'm wrong!). So it would seem to be ideal for a space probe that needs to go somewhere far far away from the sun and for which a low thrust high impulse drive (like ion propulsion) that requires large amounts of electric power is ideal. Maybe it's because the DAWN probe needed to prove the ion technology before NASA could commit a flagship mission to it.

Too bad that the isotope of Pu that they need for the probe isn't the same that is used in nuclear bombs, that would be the most apt fulfillment of the biblical(?) phrase "beating swords into plowshares". Oh well, Congress needs to fund the reactor that is used in the nuclear fuel cycle that manufactures this critical resource for space travel.

Of course this is only a stopgap until we get either the Lockheed Martin or MIT (mini) fusion reactors working!

Comment Please explain, how is court ignored? (Score 2, Interesting) 205

This is an honest question (I'm not Indian). How does the government get to override the recently passed decision by the Indian Supreme Court NOT to ban these very same sites? Is there some sort of executive order that allows the government to do so? Or is the government doing something "illegal" (I think the decisions by the Supreme Court must be the very definition of legality right?).

Comment End of Mankind? (Score 2) 312

I didn't realize that "race" could now be determined by a genetic sequence (or two). If true this may lead to some very troubling possibilities.

It would be possible using CRISPR (a recently developed means of precisely targeting an exact genetic sequence) to have a virus that could infect just one particular population. Smallpox comes to mind because 1) very few people in the world are currently vaccinated against it (it was made extinct a while ago) and 2) its DNA has been sequenced and published online. So, using a DNA synthesis machine you could make a version of this virus that would target a particular population.

I believe such machines can now make DNA sequences long enough to create viruses. I also remember someone creating a much more lethal version of smallpox that could kill all of the laboratory animals it infected, including ones vaccinated against "normal" smallpox (I think it was 100% lethal).

Of course, making a virus that would go after a particular Sex as opposed to a racial characteristic should be much easier (just target any gene found on one of the sex chromosomes and not the other.) This particular scenario was explored in Frank Herbert's book "The White Plague". A related scenario might be the film "Children of Men" where all the women(?) are made sterile.

Comment The Real Question Is... (Score 3, Insightful) 160

Will they find extra-terrestrial life IN the solar system or Outside it?

Frankly if they find it within the solar system then it would be a more significant find unless, of course, they found evidence of advanced (intelligent) life outside the solar system. It would mean that the universe is absolutely crawling with life; even if the life was somehow related to that on earth (distributed by asteroid impacts?) that would mean that panspermia is a viable method of distributing life over (at least) interplanetary distances.

In addition, it would mean that there would be a chance of someone going and really examining it within what's left of my lifetime!

So let's hope that it's on Mars (doubtful), Europa/Enceladus (possibly) or Titan. Of course if they find life on Titan, it'll have to be so radically different that our own that it'll blow the minds of just about every biologist in the world! Of course they'd be very very happy to find just fossils.

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