The Search for Life On Habitable Exoplanets 69
New submitter Benzainload895 writes "The Verge has an article about why life on other worlds would be far stranger than we might expect. They also interview some astronomers who are trying to narrow down the most likely locations for life. Quoting: 'As it turns out, the small planets with long orbits that Kepler was finding were the ones it was least disposed to find. [After estimating how often red dwarf stars have planets and taking into account their expanded habitable zones, they] came up with an estimate Cowan says is "starting to get really close to a hundred percent, where for every [red dwarf] out there you should expect there to be a habitable rocky planet." Furthermore, research exploring these planets suggests weirdness — and lots of it — in what life they might harbor. For instance, the dim light coming from a red dwarf may not be enough for plant photosynthesis like on Earth. This may lead plants to be black instead of green in order to absorb more available light. Even weirder, these planets likely don't spin as they orbit. Since red dwarfs are smaller and cooler than the sun, planets circle them at close range, creating greater tidal forces than on our planet. While the tidal force on Earth moves the ocean up and down a few meters, that force on a red dwarf planet would be so strong it'd gradually slow down the rotation of planet completely. The result? One side of the planet would face its star in a permanently sunny day, while the other side would face the stars in an endless night."
Re:We need to be more open to "life" (Score:5, Interesting)
No, Sagan wasn't looking at oxygen as a product of life, he was looking at molecular atmospheric oxygen as something that was inherently unstable, especially in the presence of methane, and very especially in the concentrations that we breathe. That meant something unusual was happening. An atmosphere rich in helium and xenon would attract attention as well, and prompt investigation. The default hypothesis would be complex radioactive processes, just like the default hypothesis for atmospheric O2 would be complex chemical processes. The discovery of artificially concentrated radioactive elements (for example) would be analogous to artificial light sources on Earth. We don't have to know what kind of things life produces, we just need to have a handle on what typical planetary evolution produces and look for variances from this norm. We'll probably end up with situations where investigators ask, "Is that life, or just an obscenely complex self-maintaining chemical process?"
magnetic field (Score:5, Interesting)