The Search for Life On Habitable Exoplanets

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"

[gstoddart]

Always looking for water looking for life, or where the 6 building blocks for life as we know it could form.

That's what we know and it makes sense, but there are surely other types of life that have different building blocks.

You know, someone asks more or less this exact question every time this topic comes up -- "why not look for other forms of life unlike our own?".

And the answer is always the same -- how do you look for something you don't know the first thing about? What do you look for? How do you look for a lifeform which has completely different biology from us? How will you know if you've found it?

If you're physically there, you can look and see. If you're doing inference from spectroscopy and the like, what, exactly, do you look for to find a bit of life which is so alien from our own that we don't have any idea of what to look for or what processes would be involved?

You can't just take random chemicals and decide that they do, or do not, suggest a lifeform we can't even imagine.

It's simply not possible to look for signs of something when you have no basis on which to even speculate what those signs would be -- because you could look at anything and say "gee, maybe that's alien life".

But you'll never know, and can never make any hypotheses or predictions. At which point, you're well outside of what can be called Science, and straight back to speculative fiction. There's really no point in trying to look for life built around other building blocks, because we don't know anything about what that hypothetical lifeform would look like or how to spot it.

I'm not saying it couldn't exist. I'm saying that until we know about it and how it works, there's no basis to look for it.