10 ms·

Evidence for nuclear explosions on Mars [pdf]

130 points by lsh123 12y ago

mullingitover 12y ago
The idea that nuclear weapons are what sterilized Mars is insane. Correct me if I'm wrong, but I always thought it was because Mars' core cooled, which caused its magnetic field to go away, resulting in all its water floating off into space. No water = sterile planet. You could shoot every nuclear weapon in the world at the Earth and life would still easily carry on (maybe not multicellular, but life nonetheless), but take all the water away...
- Netcob 12y ago
  Let's start at the beginning. The paper talks about evidence for nuclear explosions (the word "weapon" isn't mentioned as far as I can see), and then discusses natural nuclear reactors http://en.wikipedia.org/wiki/Natural_nuclear_fission_reactor http://en.wikipedia.org/wiki/Natural_nuclear_fission_reactor The author then argues that the evidence seems to fit an atmospheric explosion better, for example an asteroid that exploded in mid-air like in Tunguska. Or that the radioactive stuff just got there in this pattern through geological activities and other processes. Did I miss the part where he talks about nuclear weapons or sterilization?
  - mhurron 12y ago
    > Did I miss the part where he talks about nuclear weapons or sterilization? Yes, it's in a different link where he 'furthers' his work. http://meetings.aps.org/Meeting/PSF14/Session/G1.3 http://meetings.aps.org/Meeting/PSF14/Session/G1.3
  - huxley 12y ago
    Give this interview with Brandenburg a try: http://youtu.be/NBuN3uHnjYY http://youtu.be/NBuN3uHnjYY (courtesy of the Supreme Master Ching Hai International Association cult)
- cnp 12y ago
  You never really know until you know you don't know? What we know now is that we think we know -- that is, until we don't. Theories are meant to be superseded.
  - roywiggins 12y ago
    Extraordinary claims, extraordinary evidence, etc. The prior probability of ancient nuclear weapons is so small that there would need to be extremely good evidence to begin to shift my appraisal of how likely it is. (am I Bayesianing right?)
    - tjradcliffe 12y ago
      Close on the Bayesianing: there's no threshold, so it isn't quite correct to say you'd need extremely good evidence to "begin to shift" your appraisal. But you'd need extremely good evidence to shift your threshold very much. Bayes' rule tells us the plausibility [$] of a proposition after taking into account some evidence should be the prior plausibility times the probability of the evidence occurring if the proposition is true divided by the probability of the evidence regardless of whether or not the evidence is true, so vastly improbable occurrences that would be way more probable if the proposition was true count as very good evidence, but lots of things can shift our degree of belief a tiny little bit. However, you are correct that the prior has such a minuscule prior plausibility that it'd take astonishing evidence that couldn't be explained otherwise to raise the posterior plausibility up to "worth taking very seriously" level. Beyond that, there is the practical consideration that we impose a threshold on our beliefs for purely pragmatic reasons. Below some plausibility it just isn't worth our time to even consider the issue. So in that sense, you are Bayesianing with the best of them. [$] I am a heterodox subjective Bayesian, in that I maintain a strict separation between "plausibility" and "probability". Plausibilities are degrees of belief by a knowing subject in a proposition, and as such are inherently subjective. Probabilities are measures of the likelihood of events, and by far the most common measure is the frequency. I take orthodox Bayesiansism to be in error by identifying plausibilities with probabilities, which is what creates the great subjective/objective quango. Bayes' rule on my view is Pl(H|E) = Pl(H)*Pr(E|H)/Pr(E) where Pr = probability and Pl = plausibility.
- adventured 12y ago
  There have been over 2,000 nuclear weapons detonated in the last 70 years. There are 10,000 total warheads on earth (~4,000 active). The world could fire off every one of its functioning nukes simultaneously, and it would not come even remotely close to ending multicellular life. Most of the planet would not even notice the event; it could destroy, including the damage from fallout, an area smaller than the United States. Humans of course would likely become an endangered species were the blasts spread out targeting population centers.
- guard-of-terra 12y ago
  It doesn't have to be directly related. Maybe aliens nuked Mars when it was green, and then much later it lost its water and most of atmosphere. Also may it be that it won't happen if an advanced civilization still looked after their home world instead of being vaporized.
doubleyou 12y ago
Containing my excitement in case this is an early April Fools joke... but if this has anything to it at all it will call for an entire re-reading of many ancient texts, particularly the Sumerian, which describe war on Mars (primarily between contentious relatives a la Macbeth [a story in itself repeated in almost every culture independently]), a migration to Earth, and in the devastation, the complete destruction of a planet in our solar system, the remnants of which allegedly became our asteroid belt. This story has been repeated in a handful of ancient cultures in very specific detail. We are the aliens! explosion
- pyrois 12y ago
  The linked paper does not suggest that Martians built nuclear reactors on Mars, which then melted down. The paper suggests that there were "large fireballs in the atmosphere such as Tunguska-like events , with mid-air explosions, but of much greater energy release than Tunguska".
  - jerf 12y ago
    It is worth pointing out that at least the "natural reactor" theory is not crazy: http://en.wikipedia.org/wiki/Natural_nuclear_fission_reactor http://en.wikipedia.org/wiki/Natural_nuclear_fission_reactor Though it is unclear to me how such a process could go critical, in much the same way that one of the biggest challenges with building a real bomb fission bomb is not so much getting it to explode, but keeping it from exploding gently. Whether we have the data to parse out something to this level of detail on Mars when we're still arguing about what killed the dinosaurs on this planet I'm substantially more "meh" about. But it is not, intrinsically, impossible or stupid. The same goes for the alien hypothesis... but even taking the possibility seriously, I'd submit that A: we don't have enough evidence to eliminate the possibility that Mars could have once had an intelligent civilization but B: even moreso, let me underline that, even moreso, we have no evidence to suggest that it ever did. Such speculations would be pure science fiction right now. Right now we still know very little, full stop. And I'd observe that the stories about these civilizations, viewed through modern technological eyes have some really weird aspects to them, such as, why would a civilization with technology capable of destroying planets (and, in this case, really, really destroying them, Death Star-style, not merely sterilizing the planet which is literally ten+ orders of magnitude easier [1]) only settle on Earth after the disaster? We're not planning on waiting for Earth to go bad before heading to Mars... we're pretty much only blocked on the requisite tech and on cosmological scales the instant we have it we'll be there. There's little reason to believe that a technological civilization of that scale would actually be destroyed even by its home planet going up in smoke. I'd submit the most likely hypothesis is that they were indeed written by humans thousands of years ago, who ultimately had no idea what technology was going to look like. (Heck, even we futurists are still only grasping at smoke in terms of what we'll have 50-100 years from today, to say nothing of trying to guess thousands of years ago....) [1]: http://qntm.org/destroy http://qntm.org/destroy
huxley 12y ago
Brandenburg's been focused on this for a while, here is his 2011 theory that it was a natural fission reactor: EVIDENCE FOR A LARGE, NATURAL, PALEO-NUCLEAR REACTOR ON MARS. J. E. Brandenburg http://www.lpi.usra.edu/meetings/lpsc2011/pdf/1097.pdf http://www.lpi.usra.edu/meetings/lpsc2011/pdf/1097.pdf However, over time he has been getting deeper and deeper into pseudoscience. It was covered in Pharyngula a while back: http://scienceblogs.com/pharyngula/2014/11/22/the-two-faces-of-je-brandenburg/ http://scienceblogs.com/pharyngula/2014/11/22/the-two-faces-...
- api 12y ago
  I heard an interview with Brandenburg a while back. He sounded sane, smart, and his understanding of physics seemed sound. I can't stand this secular inquisition bullshit of cherry picking any sign of possible 'out there'-ness and using it to completely trash peoples' entire bodies of thought and work. It's anti-scientific. Please point out a problem with Brandenburg's actual published work, or go away. Even if he does hold non-traditional or strange religious beliefs, it's not relevant. Roman Catholicism is no more rational than Eastern mystic cults, so do we throw out all scientific papers by Roman Catholics? I'm not much of a fan of PZ Myers either. I read him a bit back during the mid-2000s 'intelligent design' creationist PR offensive, but stopped reading him as he got more and more shrill and irritating. IMHO Myers is as much a shrill fundamentalist as the religious bozos he constantly wars with. One interesting thing Brandenburg did say was that when he came to believe himself that Mars had been nuked, possibly in act of "biosphere genocide," the realization that this might have actually happened plunged him into a bit of a metaphysical crisis. He immediately thought of the Fermi Paradox, and that maybe the reason we're not hearing/seeing anything is because there are big nasty genocidal intelligences out there that 'cull' anything interesting from the universe. He said he actually got very depressed, and got deeper into religious/mystical stuff as part of this. That doesn't sound crazy to me, just human. Around here we've seen some IMHO irrational fears of super-human dangerous AIs circulating recently, and it seems to have led to a similar amount of metaphysical anxiety among some very brilliant and notable people in the CS field. I'm very skeptical of Brandenburg's thesis here, but I have to admit that the evidence he puts forward is very interesting. It either points to what he says -- some kind of incredibly ancient use of a nuclear device -- or an as yet undiscovered natural phenomenon that can yield a similar signature. One possibility (other than 'reaper' aliens) I can think of would be a natural nuclear reactor that actually went fully supercritical and detonated. Another would be a hypervelocity object, possibly traveling at some significant fraction of the speed of light, that impacted Mars and went thermonuclear in the atmosphere on kinetic energy alone. Maybe an asteroid or comet that got flung by a high-gravity body (black hole? neutron star?) or supernova debris could do that?
octatoan 12y ago
The xkcd was nice.

130 points by lsh123 12y ago

The idea that nuclear weapons are what sterilized Mars is insane. Correct me if I'm wrong, but I always thought it was because Mars' core cooled, which caused its magnetic field to go away, resulting in all its water floating off into space. No water = sterile planet. You could shoot every nuclear weapon in the world at the Earth and life would still easily carry on (maybe not multicellular, but life nonetheless), but take all the water away...

Netcob 12y ago
Let's start at the beginning. The paper talks about evidence for nuclear explosions (the word "weapon" isn't mentioned as far as I can see), and then discusses natural nuclear reactors http://en.wikipedia.org/wiki/Natural_nuclear_fission_reactor http://en.wikipedia.org/wiki/Natural_nuclear_fission_reactor The author then argues that the evidence seems to fit an atmospheric explosion better, for example an asteroid that exploded in mid-air like in Tunguska. Or that the radioactive stuff just got there in this pattern through geological activities and other processes. Did I miss the part where he talks about nuclear weapons or sterilization?
- mhurron 12y ago
  > Did I miss the part where he talks about nuclear weapons or sterilization? Yes, it's in a different link where he 'furthers' his work. http://meetings.aps.org/Meeting/PSF14/Session/G1.3 http://meetings.aps.org/Meeting/PSF14/Session/G1.3
- huxley 12y ago
  Give this interview with Brandenburg a try: http://youtu.be/NBuN3uHnjYY http://youtu.be/NBuN3uHnjYY (courtesy of the Supreme Master Ching Hai International Association cult)
cnp 12y ago
You never really know until you know you don't know? What we know now is that we think we know -- that is, until we don't. Theories are meant to be superseded.
- roywiggins 12y ago
  Extraordinary claims, extraordinary evidence, etc. The prior probability of ancient nuclear weapons is so small that there would need to be extremely good evidence to begin to shift my appraisal of how likely it is. (am I Bayesianing right?)
  - tjradcliffe 12y ago
    Close on the Bayesianing: there's no threshold, so it isn't quite correct to say you'd need extremely good evidence to "begin to shift" your appraisal. But you'd need extremely good evidence to shift your threshold very much. Bayes' rule tells us the plausibility [$] of a proposition after taking into account some evidence should be the prior plausibility times the probability of the evidence occurring if the proposition is true divided by the probability of the evidence regardless of whether or not the evidence is true, so vastly improbable occurrences that would be way more probable if the proposition was true count as very good evidence, but lots of things can shift our degree of belief a tiny little bit. However, you are correct that the prior has such a minuscule prior plausibility that it'd take astonishing evidence that couldn't be explained otherwise to raise the posterior plausibility up to "worth taking very seriously" level. Beyond that, there is the practical consideration that we impose a threshold on our beliefs for purely pragmatic reasons. Below some plausibility it just isn't worth our time to even consider the issue. So in that sense, you are Bayesianing with the best of them. [$] I am a heterodox subjective Bayesian, in that I maintain a strict separation between "plausibility" and "probability". Plausibilities are degrees of belief by a knowing subject in a proposition, and as such are inherently subjective. Probabilities are measures of the likelihood of events, and by far the most common measure is the frequency. I take orthodox Bayesiansism to be in error by identifying plausibilities with probabilities, which is what creates the great subjective/objective quango. Bayes' rule on my view is Pl(H|E) = Pl(H)*Pr(E|H)/Pr(E) where Pr = probability and Pl = plausibility.
adventured 12y ago
There have been over 2,000 nuclear weapons detonated in the last 70 years. There are 10,000 total warheads on earth (~4,000 active). The world could fire off every one of its functioning nukes simultaneously, and it would not come even remotely close to ending multicellular life. Most of the planet would not even notice the event; it could destroy, including the damage from fallout, an area smaller than the United States. Humans of course would likely become an endangered species were the blasts spread out targeting population centers.
guard-of-terra 12y ago
It doesn't have to be directly related. Maybe aliens nuked Mars when it was green, and then much later it lost its water and most of atmosphere. Also may it be that it won't happen if an advanced civilization still looked after their home world instead of being vaporized.

doubleyou 12y ago

Containing my excitement in case this is an early April Fools joke... but if this has anything to it at all it will call for an entire re-reading of many ancient texts, particularly the Sumerian, which describe war on Mars (primarily between contentious relatives a la Macbeth [a story in itself repeated in almost every culture independently]), a migration to Earth, and in the devastation, the complete destruction of a planet in our solar system, the remnants of which allegedly became our asteroid belt. This story has been repeated in a handful of ancient cultures in very specific detail. We are the aliens! explosion

pyrois 12y ago
The linked paper does not suggest that Martians built nuclear reactors on Mars, which then melted down. The paper suggests that there were "large fireballs in the atmosphere such as Tunguska-like events , with mid-air explosions, but of much greater energy release than Tunguska".
- jerf 12y ago
  It is worth pointing out that at least the "natural reactor" theory is not crazy: http://en.wikipedia.org/wiki/Natural_nuclear_fission_reactor http://en.wikipedia.org/wiki/Natural_nuclear_fission_reactor Though it is unclear to me how such a process could go critical, in much the same way that one of the biggest challenges with building a real bomb fission bomb is not so much getting it to explode, but keeping it from exploding gently. Whether we have the data to parse out something to this level of detail on Mars when we're still arguing about what killed the dinosaurs on this planet I'm substantially more "meh" about. But it is not, intrinsically, impossible or stupid. The same goes for the alien hypothesis... but even taking the possibility seriously, I'd submit that A: we don't have enough evidence to eliminate the possibility that Mars could have once had an intelligent civilization but B: even moreso, let me underline that, even moreso, we have no evidence to suggest that it ever did. Such speculations would be pure science fiction right now. Right now we still know very little, full stop. And I'd observe that the stories about these civilizations, viewed through modern technological eyes have some really weird aspects to them, such as, why would a civilization with technology capable of destroying planets (and, in this case, really, really destroying them, Death Star-style, not merely sterilizing the planet which is literally ten+ orders of magnitude easier [1]) only settle on Earth after the disaster? We're not planning on waiting for Earth to go bad before heading to Mars... we're pretty much only blocked on the requisite tech and on cosmological scales the instant we have it we'll be there. There's little reason to believe that a technological civilization of that scale would actually be destroyed even by its home planet going up in smoke. I'd submit the most likely hypothesis is that they were indeed written by humans thousands of years ago, who ultimately had no idea what technology was going to look like. (Heck, even we futurists are still only grasping at smoke in terms of what we'll have 50-100 years from today, to say nothing of trying to guess thousands of years ago....) [1]: http://qntm.org/destroy http://qntm.org/destroy

huxley 12y ago

Brandenburg's been focused on this for a while, here is his 2011 theory that it was a natural fission reactor: EVIDENCE FOR A LARGE, NATURAL, PALEO-NUCLEAR REACTOR ON MARS. J. E. Brandenburg http://www.lpi.usra.edu/meetings/lpsc2011/pdf/1097.pdf http://www.lpi.usra.edu/meetings/lpsc2011/pdf/1097.pdf However, over time he has been getting deeper and deeper into pseudoscience. It was covered in Pharyngula a while back: http://scienceblogs.com/pharyngula/2014/11/22/the-two-faces-of-je-brandenburg/ http://scienceblogs.com/pharyngula/2014/11/22/the-two-faces-...

api 12y ago
I heard an interview with Brandenburg a while back. He sounded sane, smart, and his understanding of physics seemed sound. I can't stand this secular inquisition bullshit of cherry picking any sign of possible 'out there'-ness and using it to completely trash peoples' entire bodies of thought and work. It's anti-scientific. Please point out a problem with Brandenburg's actual published work, or go away. Even if he does hold non-traditional or strange religious beliefs, it's not relevant. Roman Catholicism is no more rational than Eastern mystic cults, so do we throw out all scientific papers by Roman Catholics? I'm not much of a fan of PZ Myers either. I read him a bit back during the mid-2000s 'intelligent design' creationist PR offensive, but stopped reading him as he got more and more shrill and irritating. IMHO Myers is as much a shrill fundamentalist as the religious bozos he constantly wars with. One interesting thing Brandenburg did say was that when he came to believe himself that Mars had been nuked, possibly in act of "biosphere genocide," the realization that this might have actually happened plunged him into a bit of a metaphysical crisis. He immediately thought of the Fermi Paradox, and that maybe the reason we're not hearing/seeing anything is because there are big nasty genocidal intelligences out there that 'cull' anything interesting from the universe. He said he actually got very depressed, and got deeper into religious/mystical stuff as part of this. That doesn't sound crazy to me, just human. Around here we've seen some IMHO irrational fears of super-human dangerous AIs circulating recently, and it seems to have led to a similar amount of metaphysical anxiety among some very brilliant and notable people in the CS field. I'm very skeptical of Brandenburg's thesis here, but I have to admit that the evidence he puts forward is very interesting. It either points to what he says -- some kind of incredibly ancient use of a nuclear device -- or an as yet undiscovered natural phenomenon that can yield a similar signature. One possibility (other than 'reaper' aliens) I can think of would be a natural nuclear reactor that actually went fully supercritical and detonated. Another would be a hypervelocity object, possibly traveling at some significant fraction of the speed of light, that impacted Mars and went thermonuclear in the atmosphere on kinetic energy alone. Maybe an asteroid or comet that got flung by a high-gravity body (black hole? neutron star?) or supernova debris could do that?

octatoan 12y ago

The xkcd was nice.