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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."
Should become nice and warm, I hope! ;)
You mean we will watch how they died off millions of years ago, right?
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More than likely, we'll WMD ourselves into microbes by then.
Table-ized A.I.
If the sun is turning into a red giant and toasting our planet to a cinder, the biosignature of earth is a tiny footnote to the real event. Who cares if the plants die of a lack of CO2 right before they are incinerated? The main event is the star.
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.
Makes it seem like we're sociopaths. Also Alpha..if it takes 2 billion years to die off that's a pretty decent window. 1/9 the age of the universe is a pretty good length of time. Especially when you consider the beginning of Universe type galaxies and the absense of clusters...
This signature is set to change dramatically in future. As the Sun begins to heat the planet, one of the counterintuitive effects will be a dramatic drop in the levels of carbon dioxide in the atmosphere.
This happens because more carbon dioxide dissolves in the oceans making them acidic and reacting with rocks to form clays. Essentially, the carbon becomes trapped in sediment on the ocean floors.
So, why would the oceans absorb more CO2? Other sources tell me that warming oceans would absorb less CO2. Why would this happen in reverse in the far future? That seems important since it sets up the rest of the process.
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.
Well, thanks, Slashdot. First we get a story about a fucked-up asshole shooting up a TSA line full of innocent people at LAX, so to follow it up, we obviously need an uplifting story about how all life on earth will be eradicated by the inevitable end-of-life of our sun!
The bit about having all the CO2 absorbed by the oceans doesn't make a lot of sense. Water can dissolve more (soluble) solids as the temp increases, but the solubility of gasses goes DOWN with increasing temperature. Not that I would expect the reporter to know this or ask about it - it isn't Ars, after all.
There is nothing we can do about global warming, and so we shouldn't be destroying the world economy to fight it.
This really is too bad. Not that the Earth is going to die, but that humanity does not possess the necessary skills in cooperation and teamwork to move our collective asses somewhere else before it happens.
If we get enough know-how, we can just build our own habitable spaces in space itself...
Quo usque tandem abutere, Nimbus, patientia nostra?
Party like its 1000002013!
These are the same scientists who predicted a horrible, horrible hurricane season this year, due to "global warming"?
Even without heating, the concentration of CO2 has been steadily dropping over geological history. This is due to organic sediments that are pulled away from the surface by the tectonic activity. Occassionaly these rise to the surface but only as stones (calcium-carbonate mountains). CO2 is replenished by vulcanism which was probably much violent in the past.
Once oceans boil, tectonic activity will stop (yes, oceans are responsible for plate tectonics) and earth will become more like venus (geologically) - a volcanic turmoil every 300 million years that recreates the surface.
We have 1 BN years to make earth reflect more sunlight though..and we could produce carbon-dioxide from CaCO3. There is time to save the earth, at least until the sun expands.
Look, it didn't take a research project to figure it out either!
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When I first read this I sat straight up in my chair because thought it said one million years, then realized it said one billion years.
"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."
That's very comforting. It's always better to not be the one dying.
That's when the temperature will have risen enough due to the sun increasing in luminosity to preclude liquid water on Earths surface.
Niven's World out of Time story had a plausible method for boosting the Earth to a higher orbit. Drag it behind a gas giant. Moving the gas giant itself was a bit more of a problem, but he had this magical planetary sized fusion rocket motor that used the gas of the gas giant as its fuel. His Known Space and Ringworld stories have the Puppeteer civlization's planets on an interstellar trip powered by some magical motor provided by extremely advanced aliens.
Don't know if the energy required to move the Earth would be better spent on terraforming efforts. Probably would be. But if not, and assuming we don't kill ourselves off, our descendents, Homo Sapiens XLII or whatever, will probably find a way to move the Earth.
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As the sun becomes bigger in mass. All those invested solar panels will pay off.