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Nearby Supernova Causes Mass Extinction?
hcg50a writes "AP has a
story on Yahoo about a theory that a blast of gamma rays from a distant supernova destroyed the earth's ozone layer, allowing normally shielded intense UV radiation from the sun to kill life on earth. The second-largest extinction in the Earth's history, the killing of two-thirds of all species, may have been caused by ultraviolet radiation from the sun after gamma rays destroyed the Earth's ozone layer. Astronomers are proposing that a supernova exploded within 10,000 light years of the Earth, destroying the chemistry of the atmosphere and allowing the sun's ultraviolet rays to cook fragile, unprotected life forms."
Could this also have affected life on Mars, but it never recovered?
(Rhetorical question - we can't really know)
They should have been using sun-bloc SPF-10,000,000
A supernova that's really nearby (such as our own sun) could put a huge damper on things, as far as life is concerned.
I can't say that I don't give a fuck. I've just run out of fuck to give.
Where's the nebula? We should be able to see the remains of a close-by super nova.
Thanks.
Paper out on drive J:
Life on Earth would have already been taken out by the Sun's death throes. Carl Sagan had a great explanation of this in COSMOS.
LOAD "SIG",8,1
I'm not sure if other hard-sci-fi authors have addressed this, but Stephen Baxter's Manifold Space used a theory like this to address the Fermi Paradox: if we assume that physical laws are constant throughout the universe, why hasn't there been contact with other species? His answer? A sort of galactic reset.. When conditions are just right, two neutron stars (or other heavy bodies) will enter a decaying orbit, and release gravitational energy in the form of gamma rays (I believe.) In short, resetting the biological clock of our galaxy. Different from destroying the ozone layer, but this article makes it seem a little less far fetched, doesn't it?
This statement is false.
... has saved us!
"Derp de derp."
In 2003 this story was reported in nature.
And here the link to the pre print.
Jere H. Lipps, a paleobiologist at the University of California, Berkeley, said gamma rays as a source of the Ordovician extinction should be regarded as only one of several theories. "It is a hypothesis that should be tested," Lipps said.
Tested? How?
is in the article.
The galaxy has completed two rotations since the event, and given that the various components of the galaxy don't rotate perfectly synchronously, the remenant nebula is either not where you'd expect, or smeared out of all recognition.
The article clearly states that they have no real evidence to speak of. The only thing they do have is the ice age that occured at the time of the extintion. They admit that no traces of a supernova near earth can be found, and blame it on the rotation of the Milky way.
Melott said there is no known evidence of such a nearby supernova, but that in 440 million years the Milky Way would have rotated almost twice and traces of the explosion could have been moved during that time.
I will give them that it is a possibility, but until they have some more convencing evidence I'm not ready to jump aboard.
Could it also be a factor in Evolution?
Increased exposure to radiation causing a period of increased mutations in the surviving species?
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a gamma ray beam striking the Earth would break up molecules in the stratosphere, causing the formation of nitrous oxide and other chemicals that would destroy the ozone layer and shroud the planet in a brown smog.
Didn't evidence for extraterrestrial origin of K-T extinction start with findings of strange isotope ratios in the rock layers? Shouldn't we see evidence of this brown smog in layers of sedimentary rocks? Have we been looking?
I'm sorry, I can't lend my reputation to this theory.
There was supposed to be an earth-shattering Ka-Boom!!!
I believe this is very possible. We still haven't completely figured out GRB's, let alone the universe. I believe that mass extinction would be likely in any planet old enough to achieve the technology to determine it, and this due only to the lenght of time which presents opportunities for such events to take place. Sure, there's no proof, but it's interesting.
A blog like any other.
Meanwhile, geologists and archeologists debate the introduction of the Delicious Period to historical texts.
Dewey, you fool! Your decimal system has played right into my hands!
Like any good Slashdot reader, I haven't read the article, but if it says that the event killed off 2/3rds of the creatures here, then that implies that 1/3 were fine and survived.
If that is the case, then they would have some protection strategy towards UV - are those animals currently still here? Humans sure as hell don't have that protection.
And is that number only considering land/air based creatures - would it have any impact on sea life?
It just would seem that if the ones that could survive the UV were the only one's to remain, then there would be a larger amount of creatures on earth (do plants care?) that were UV agnostic than there currently are.
There are some odd things afoot now, in the Villa Straylight.
Then you would not have to ask that question.
is insufficient to answer you with any authority.
However, I'll offer a guess or two - First, a gas giant will collect anything in a solar system's disk that is slowly spiralling inwards, as even if it isn't very close, it only has to pass close enough to perturb the path, drawing the object closer for the next pass. Second, (and this is a wild-ass guess) there may be other effects of a large gravitational field on chaotic structures (like asteroid belts?) that keep them dynamically stable and less likely to plummet bits of themselves towards the Sun.
Anybody who actually understands this in enough detail to explain the current theory is invited to confirm, correct, or expand on this.
is Greg Egan's Diaspora, in which a gamma-ray burst in a nearby pair of neutron stars lays down some heavy spank on Planet Earth. The predicted/imagined effects are pretty-well thought out, and would make for a stunning series of special effects.
There's a references section at the end, which lists some nonfiction texts concerning GRBs and the possibilities of their existence.
You cannot apply a technological solution to a sociological problem. (Edwards' Law)
and here's the ticking time bomb within 10,000 lightyears that's going to finish us off. It may in fact already have supernovaed, and the gamma ray clam-bake coming at lightspeed! Oh, and recently revised estimates indicate no more than 20,000 years to the big pop. This will mess up your hard disk.
This is a scenario that has appeared in science fiction before in, for example, Charles Sheffield's Aftermath and Starfire.
What sticks in my mind is the thought that on a cosmic scale, these things happen. Whether it's meteor strikes, runaway greenhouse effects, or nearby supernovae, the universe/mother nature doesn't care. The universe is a scary place. It's just that we're around to complain about it now.
The Crab Nebula is a remnant of a supernova less than 10,000 light-years away. Why didn't we all fry back in 1054?
"Zone" implies associating a boundary to a region. Therefore, the anthropic principle does not automatically resolve the issue of whether only part of the galaxy can support life.
So how long would this "blast wave" of energy once it reaches Earth and beyond? Would it last for 5 seconds, or a few days? If it's less then a 24 hour period, maybe Humans by then could calculate the time of impact and thus shild themselves by moving to the other side of the Earth. Once the event is over, just take a jet and fly back home to your own country.
Life is not for the lazy.
Quite true, but a supernova is a really, really big bang. A star going supernova within a few light-years will cook us quite nicely. Sirius A, for example, is certainly large enough to supernova, and it's 8.6 light-years away. I don't have the numbers, but I strongly suspect that the gamma-ray flux from something that close would do a whole lot more than just hurt the ozone layer... not to mention the blast of particle radiation, moving at less than C, that would follow some time later.
--Larry
Never attribute to malice that which is adequately explained by incompetence