Sea Life Wiped Out by Neutron Star Collision? 726
Memorize writes "Scientists report in the Journal of Astrophysical Letters that a mass extinction of marine life 450 million years ago might have been caused by radiation from an exploding star, such as a collision between two neutron stars, or a neutron star collapsing into a black hole. Such an event would cause a ten-second burst of gamma radiation, and if it occurred within our galaxy, it could have wiped out many species on earth. At least if astronomers find out that an asteroid is heading our way, we can do something about it, but if there is a gamma burst, we get no warning. And if we did, would there be any way to protect the planet?"
Where's the science? (Score:5, Interesting)
Greg Egan's Diaspora (Score:5, Interesting)
No - we're doomed. (Score:5, Interesting)
I suppose we could make a REALLY good predictive model of when astronomical objects are likely to do this - and predict the arrival of a gamma ray burst in time to do something about it. But what could we possibly do?
It takes a good few inches of lead (or a good few feet of concrete, dirt, whatever) to significantly attenuate gamma rays - and if the ones were are talking about were powerful enough to get through the full depth of the earth's oceans and still kill things when they got there - then you'd need to wrap the earth in a few feet of lead - or hide down some amazingly deep mine-shafts.
Since gamma rays are electrically neutral, you can't deflect them away with magnets or anything like that.
We'd have to get out of the way - but this radiation will be expanding out equally in all directions from the source. Unless we had thousands of years of warning, we'd have to high-tail it outta here at close to the speed of light in order to get far enough away for the inverse-square law to have an effect. If we're 100 light years from the source (say) and a mile of salt water doesn't attenuate the energy enough - then we'd need to be *way* more than 200 light years away if we could carry a quarter of a mile of water as a shield, 400 light years away if we had a sixteenth of a mile of water....for any reasonable amount of shielding, we need thousands of years notice of the problem happening.
In all likelyhood, we'd just sit back and let our great, great, great grandchildren deal with the problem.
We're basically doomed unless we have some kind of science-fiction technology.
Re:No. (Score:3, Interesting)
Shielding for ? rays requires large amounts of mass. The material used for shielding takes into account that gamma rays are better absorbed by materials with high atomic number and high density. Also, the higher the energy of the gamma rays, the thicker the shielding required. Materials for shielding gamma rays are typically illustrated by the thickness required to reduce the intensity of the gamma rays by one half (the half value layer or HVL). For example, gamma rays that require 1 cm (0.4 inches) of lead to reduced their intensity by 50% will also have their intensity reduced in half by 6cm (2.4inches) of concrete or 9cm (3.6inches) of packed dirt.
Re:No. (Score:3, Interesting)
I wonder... (Score:3, Interesting)
Easy answer (Score:5, Interesting)
Uh, no? First, how would you propose we detect a gamma ray burst, which travels at the speed of light (of course), before it gets here? Second, you're talking about a pulse of energy strong enough to destroy life on a planetary scale from 6,000 light years away! How the hell are you going to protect against that?! Tin foil can't help you now!
On a side note, this was a plot device in a book by Stephen Baxter, although I can't remember the title. Every couple million years, two stars in the center part of the galaxy would collide, and knock all life in the galaxy back to single-stage or before; species would struggle back up the evolutionary ladder, and just as they achieved spaceflight, the next stars would collide. Great book-
Re:There is a solution (Score:3, Interesting)
Re:Scary Stuff (Score:1, Interesting)
Remember, fear leads to anger, anger leads to hate, hate
Re:Yet another reason (Score:3, Interesting)
Normally, I'd say travel to other worlds is largely useful to protect against man-made disasters, but some of the technology needed to make other worlds livable without special habitats could actually help in this case.
Wait... did I just say that our President isn't entirely full of it? Well, maybe just this once....
Re:Scary Stuff (Score:2, Interesting)
I remember reading about this somewhere also. It like a flashlight; if the main beam hits you, you're hosed. However, if it misses you, you are safe unless you are pretty close to the thing such that the side radiation will get you. Somebody apply called it galactic russian reulette.
Re:Scary Stuff (Score:5, Interesting)
Exept that our galaxy is a disc, not a sphere. Also, don't forget that we're towards the edge of that disc.
Personally, I see 6000 lt-yr still being pretty "close" (and probably "unlikely") when you consider our galaxy is roughly 100,000 lt-yr in diameter. If it happened often enough for us to be worried about, we'd see more such collisions within our galaxy beyond the 6000 lt-yr theoretical safe distance.
Besides, what are the odds of two stars colliding such a manner, anyway? It seems the odds of a binary star becoming a pair of neutron (or denser) stars seem to be slim to none: you'd think the creation of one neutron star out of one would consume/destroy the other before it had the chance to follow suit. So we're really dealing with an intersection of two previously unassociated stars. And it's called "space" for a reason.
I'd worry more about comets and asteroids at this point and put this one in the category of "When we have to start worrying about it, we'll probably be advanced enough to do something about it," kinda like the sun going nova.
C'mon (Score:3, Interesting)
Re:Black holes do not exist (nature.com) (Score:2, Interesting)
not anymore (Score:2, Interesting)
They might be "an idea's way to make more ideas", since what humans do is mainly governed by culture, not genes. But even that is simplistic, since the actual contents of ideas matters. Some are morals, beliefs or scientific theories, all of which can utterly change the trans mission patterns of ideas, and human dynamics in general.
Maybe it should happen (Score:1, Interesting)
The fact is that we're nothing on the grand scale. I do believe we should fight for our survival, but it also depresses me that when we're all dead and our bodies progress from ferterlizer to oil, the planet may not actually recover completely from the damage that we've done. Someday, a new race of animals with "intelligence" enough to learn to engineer etc... will look for oar and other basic supplies and dig up our garbage. It just seems embarressing.
As for the human race, we'll survive for a while longer. I figure we have at least 1,000 more years of ruining the planet before we have used all our natural resources up and will have to live like something out of a bad Kevin Costner movie.
Re:No - we're doomed. (Score:3, Interesting)
Re:No. (Score:3, Interesting)
Magma outpourings more likely than gamma burst (Score:2, Interesting)
For instance, the greatest mass extinction that occured at the end of the Permian Period was associated with the largest surface outpourings of magma that the earth has ever experienced. These episodes poison the air and the water on a worldwide basis. No need for hypothetical gamma bursts to explain the largest extinction.
Re:Scary Stuff (Score:1, Interesting)
From that perspective, my personal death is NOT as important as the continuation of my children.
If THAT'S your worldview, then you must admit that NEITHER of those things is "important". ("Important" implies some kind of moral law.)
Re:Yet another reason (Score:2, Interesting)
Neutrino Detector... (Score:5, Interesting)
Photons (gamma rays) take a long time to get out of a star. But neutrinos, because of their physical properties, pass right through most of the star. Most nuclear reactions that generate photons also generate neutrinos. They're just very hard to detect (because of that same physical property).
Well, I'm working on a neutrino detector at the South Pole right now. http://icecube.wisc.edu/ [wisc.edu]
It could, when it's complete, pinpoint the source of the neutrinos. Given the energy level of the neutrinos and the sudden, large burst of them, a whole lot of scientists are going to be woken up - and I mean that literally.
An earlier version of the project, AMANDA http://amanda.wisc.edu/ [wisc.edu], already has a supernova detector. It hasn't gone off yet, but when it does it will start a sequence of events that ultimately steers a lot of telescopes to point at that supernova.
You might've read it but you missed the point (Score:2, Interesting)
What we seem to think we can do is beat them to it (Score:2, Interesting)
The planet, and its life, is being destroyed in a
much less spectacular, because much more gradual, way by humans currently.
bjd
Not as bad as it sounds. (Score:2, Interesting)
Re:Loss of ozone (Score:3, Interesting)
Additionally, last I've heard about the other gamma-ray based extinction, the problem wasn't just wiping out the ozone layer, but replacing it with a brown layer of nitrous oxide. It caused, if I remember right, a massive glaciation that lasted a million years.
Think the "nuclear winter" theories. Same idea here, except that instead of a layer of dust blocking the sun, you have a thick brown layer of nitrous oxide.
So I'll say that while it might not make humans really extinct, it will very likely make their life a living hell. Well, the Norse frozen hell, rather than our burning brimstone one, but not a comfortable place to be in anyway.
Re:Neutrino Detector... (Score:3, Interesting)
Re:Easy answer (Score:4, Interesting)
Believe it or not, we have 3/4ths of our planet literally covered in one of the simplest ways known to block high-energy photons - Water.
The GRB in question killed sea life.
living deep inside a skyscraper won't save you. Living on the far side of the planet would, at least on the short-term, but the longer-term consequences of a GRB sterilizing one side of the planet would not leave the Earth a very health place.
Re:Scary Stuff (Score:1, Interesting)
I care about neutrinos! (Score:3, Interesting)
Consider this:
As I'm sure you know, neutrinos very rarely interact with matter, but they do interact. Now, currently we are bathed with a flux of approximately 5,000,000 neutrinos/cm^2/s (could be off by a factor of 3, and depends on what kind of neutrinos you're talking about). At this flux, interactions are extremely rare and we have to set up huge tubs of water or cleaning fluid in order to detect them. However, what if the flux was not 5 x 10^6, but was on the order of 10^10? Well, I don't know, but I expect we'd still be OK, although we suddenly would be exposed to an increased amount of radiation from the 10,000-fold increase in neutrino interactions. We might even notice the occasional flashes in our retinas (although I doubt it). Now, what if that was increased to 10^30 neutrinos/cm^2/s? Now we're talking about an increase similar to Avogadro's number. I'm fairly certain we would notice that, and I expect it would not be healthy. Perhaps I'm wrong about that, but I'm certain you agree that there's some flux of neutrinos that definitely qualifies as being "a very bad thing".
Re:Neutrino Detector... (Score:3, Interesting)
The neutrino gets out pretty much at the speed of light.
The problem is, you're talking about a different reaction. It's dependent on whatever reaction is causing the gamma-ray burst. Ask a physist how long the collision takes.
If we really are talking a collision, though, I'd say there's also a possiblity of gravity waves getting out well before the gamma ray burst. Another indicator that somethings about to pop. And another technology that's on the verge of being possible.
Details you might want to know (Score:4, Interesting)
- Supernovae may not be predictable, but mergers of neutron stars may be. If theory of gravity waves is correct, we could detect the orbital spin-ups before mergers using laser interferometers.
- If you can stick enough mass in the path of the burst to scatter the gamma rays to lower-energy photons or deflect them entirely, you could prevent this problem. This means having a disc of material at least 8000 miles across in the exact right place to shadow the Earth at the moment of the burst, but I never said it would be a small job.
From this, it follows that long-baseline laser interferometers and GRB research are good things for now. Aiming for serious space-construction capability is a good long-term goal.Ozymandias (Score:5, Interesting)
I met a traveler from an antique land
Who said: Two vast and trunkless legs of stone
Stand in the desert. Near them, on the sand,
Half sunk, a shattered visage lies, whose frown,
And wrinkled lip, and sneer of cold command,
Tell that its sculptor well those passions read,
Which yet survive, stamped on these lifeless things,
The hand that mocked them, and the heart that fed,
And on the pedestal these words appear:
"My name is Ozymandias, King of Kings:
Look upon my works, ye Mighty, and despair!"
Nothing beside remains. Round the decay
Of that colossal wreck, boundless and bare
The lone and level sands stretch far away.
Sound familiar?
Re: The Biology of Senesence (Score:4, Interesting)
However, the question with regard to rate is of the utmost importance in self-replicating systems. Bacteria in a sense do not die, in that they clone themselves (albeit with sometimes intermittant reproduction through genetic exchange with other bacteria) and hence in a sense are immortal (they make identical copies of themselves which persist more or less indefinitely).
Studies of the aging process (ie genes controling catabolism relative to anabolism) in eucaryotic organisms suggest that genetic systems have evolved genes that actually shorten life span. Hence, the question arises as to why, since one might initially assume that being able to live forever (like bacteria) would seem a more effective reproductive strategy.
It turns out that there appears to be selection for genes that produce shorter life spans in situations in which the presence of such genes increases the probability of survival of the offspring, even if their activity/presence takes place at the expense of the parent. It would seem that perpuation of self-replicating systems necessarily requires the need to take some risks to overcome the reality of dynamic environments. Ones current genetic makeup although nearly optimal (or more apply sufficiently near optimal) in the current environment may not be so in a future environment. Hence, a slightly different genetic makeup in ones offspring may be selected for in some future environment. Since prediction of exactly what the future environment might be is to some degree uncertain, most sexual organisms are capable of having more than one offspring, thereby increasing variety and hence the probability that at least some will be nearly optimally suited to survive.
Keep in mind, however, this is only an evolutionary strategy. While only those gene combinations that are successfull in reproducing will persist in subsequent generations, there is no guarantee that a particular gene combination will survive.
As for your arguments regarding "genes not grading anything in levels of mportance or having a perspective", this is really little more than a matter of semantics. The adult phenotype is nothing more than the product of its genes acting in an environment during its ontogeny. While it might seem to we are something more than our genes, at a molecular level there is nothing about us that is not the direct result of metabolic processes that occur (or occurred) as the direct result of the collective response/relative control of our genes to our environment. However, when you consider the shear number of different variatnts of tens of thousands of human genes and the incredible diversity of their responses to slightly different kinds of environments, the complexity is truely something to marvel at; so much so that it is hardly worth worrying about whether or not "something" (like some kind on mystical spiritual essesence or soul or other such unecessary nonsense) is missing.
Re: The Biology of Senesence (Score:3, Interesting)
Please enlighten me.
Re:What about Betelgeuse? (Score:2, Interesting)
Alright, I'm going to be really generous in my calculations here...
Assume Betelgeuse has a mass of about 15 solar masses (estimates vary between 12 and 17 solar masses), or about 3e31 kg. Now, assume that (and here's the generous part) the star converted 10% of its mass at the time of supernova into photons, and this burts only happened for 1000000 seconds (a week or so, minescule in the grand scheme of things). Taking E=mc^2, like one always should, that's a total power of about 3e41 watts. Fantastic.
Now, assume the diameter of the Earth is about 1.2e7 m, and the distance between earth and Betelgeuse is 425 lightyears, or say... 4e18 m. That means, from Betelgeuse, Earth subtends a whole 4e-24 steradians of the sky. Better put, only about 6e-23 percent of the light from Betelgeuse reaches Earth.
So, some quick math, and that gives us about 1e3 watts per square meter. That's a factor of 10 smaller than what the sun imparts to us on a day-to-day basis, so we really have nothing to worry about. The long and the short of it is, it will be very easy to see at night for about a week, but don't go stocking up on suntan lotion.