Saturday, February 5, 2011

Science Saturday: Another Earth?

So, I thought I'd start a new regular feature on the blog.  Kari's weekend is Sunday-Monday, so our Saturday night is like everyone else's Friday night.  Normally this could and should be spent at a bar somewhere listening to live music, but in case my readers haven't noticed by now, I'm quite broke.  Thus, Saturday night has evolved into a tradition wherein Kari and I catch up on our science documentaries for the week to reasonably-priced South American wine and/or cocktails.  Since my blog is a reflection of my life, I figured I should extend it to here.  So, without further ado, I give you Science Saturday.

Since this week brought us the announcement of the NASA Kepler Mission findings, I figured I'll kick us off with this little nugget: the discovery of five possible Earth-like planets.  My rudimentary scanning of the data has yet to tell me much about the stars these planets orbit, only that they're smaller than the sun.  As you might know, stars much smaller than .4 solar masses are so dim and cool that a planet in the star's habitable zone would be orbiting so close, it would be tidally locked to its star.  This means that the orbiting planet's day exactly equals its year, meaning one side of the planet is always facing its star.  Astronomer Neil F. Comins provides a fantastic in-depth explanation of how this works in his excellent book What if the Earth Had Two Moons? And Nine Other Thought-Provoking Speculations on the Solar System, which you should totally read, but I'll give the premise a basic work-through here.  Despite what Bill O'Reilly says, the moon and Earth's proximity to one another causes their gravity to exert itself on one another, which causes tides.  Tides, among other things, slow down each body's rotations (dependent on the relative force of gravity being exerted on one another), which over millions or billions of years eventually grinds things to a halt.  This is why the moon appears to have a "dark side": one side of our moon is always facing the Earth.  The principle is the same, only swap the moon for a planet and the Earth for a star.  We don't know much about the evolution of things like atmospheres or life on these planets because we haven't been able to study any of them directly, but we do know these worlds exist (Gliese 581 is one such planetary system), but computer models suggest the possibilities for life aren't promising (See Chapter 8 of Two Moons).

So here's hoping the stars these planets are orbiting have just enough mass, like Alpha Centauri B that the star's habitable zone isn't so close to itself.  'Cause, damn it, if I can't have flying cars, I want some proof of alien life, even if it's just microbes.

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