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How Earth's Biosignature Will Change As the Planet Dies
KentuckyFC writes "As the Sun expands into a red giant, life on Earth will die away. Now astrobiologists have worked out how this will look to distant observers watching the biosignature in our atmosphere. They say the first major effect of warming, about 1 billion years from now, will be a dramatic drop in atmospheric carbon dioxide as the oceans absorb more of it. That's bad news for trees and plants, which need carbon dioxide for photosynthesis, so they begin to die off. Since plants produce oxygen, atmospheric levels of oxygen will also drop, killing off the animals. Roughly 2 billion years from now, the only living things on Earth will be microbes. However, methane levels will have risen dramatically, caused by decaying plant matter. And decaying animals will release a gas called methanethiol, which breaks down into ethane, which ought to be visible too. Finally, they calculate that about 3 billion years from now, the oceans will boil and Earth will be a barren planet with little if any biosignature at all. But all this is not just a subject of morbid fascination. With the next generation of space telescopes, astronomers should see similar biosignatures on Earth-like planets around other stars that are also beyond their sell-by dates. So we'll be able to watch them die off first."
The furthest planet that we have found yet is 21,500 ± 3,300 light years away according to Wikipedia. Unless they are going to get far better telescopes, I don't think it will be millions of years old.
The original paper on the very first page of the introduction, says atmospheric CO2 drawdown will reduce CO2 concentration in the oceans, not increase absorption. The latter doesn't make sense anyway, because the solubility of CO2 goes down as temperature goes up.
I had no idea it was that close. I had never read anything about when the sun would be significantly effecting life, just that in 3-4 the planet would unlivable.
1 Billion is pretty small in planetary time, we are in the twilight of earth's life supporting existence, you could say.
Troll is not a replacement for I disagree.
It took 4.5 billion years out of a 5.5 billion year window for intelligent life to evolve.
That has to signficantly reduce the odds of finding other intelligent species.
The sun's death will be a very slow one. Also, it's important to remember the scale of things. By the time the sun 'engulfs' the inner planets, its atmosphere will still be extremely diffuse near the Earth's orbit. Much closer to a vacuum than what we think of as an atmosphere.
I read TFA and all I got was this lousy cookie
If it's any comfort your own personal end of life will happen long before that.
Seven puppies were harmed during the making of this post.
If we don't die off in a billion years. In a billion years I'm sure we'll have infected most of the solar system with life.
Free Martian Whores!
Nobody has indicated a scenario by which this could happen.
Wrong - http://en.wikipedia.org/wiki/Runaway_climate_change#Current_risk
There is some good science supporting this... if you believe in science. If you're a denier then keep your head in the sand.
From the "Proceedings of the National Academy of Sciences":
"We found that a 21-degree warming would put half of the world's population in an uninhabitable environment,"says study co-author Matthew Huber of Purdue University. While the Intergovernmental Panel on Climate Change found that the result of business-as-usual warming would be 7 degrees by 2100, eventual warming over several centuries of 25 degrees is feasible, says Huber. The new research calculated the highest tolerable "wet-bulb" temperature that humans can withstand."
http://content.usatoday.com/communities/sciencefair/post/2010/05/report-climate-change-could-render-much-of-world-uninhabitable/1#.UnRNdCS-Pfk
http://www.independent.co.uk/environment/earth-may-be-too-hot-for-humans-by-2300-study-1970969.html
I don't read your sig. Why are you reading mine?
One more article on the topic
http://www.nature.com/ngeo/journal/v6/n8/full/ngeo1892.html
"A runaway greenhouse could in theory be triggered by increased greenhouse forcing, but anthropogenic emissions are probably insufficient."