Planets, planets everywhere – but life’s another matter

Today my emailbox yielded several announcements about extrasolar planets, all announced this week at the American Astronomical Society’s annual meeting – an event that scientists save up news for, as AAS has a well-oiled PR machine in place, and a large media following, to get the word out on new discoveries.

Findings of “real-life ‘Tatooine’ planets with two suns”*, a Mars-sized and ostensibly rocky planet, and “more planets than stars” in our Milky Way galaxy are today’s news. According to the Space Telescope Science Institute, “The Milky Way contains at least 100 billion planets.”

So of course we’re bound to find life on another planet soon. It’s inevitable, right?

And we can safely assume that where life has evolved, there will be intelligent life, yes?

Nope, and nope.

The most interesting insight I’ve extracted from the last decade of extrasolar planet searching is that there’s no such thing as a typical planet or planetary system. These days our own solar system, once thought “average,” looks about as typical as a two-headed cow: proved possible but not proved common.

At the same time, the last decade of research on boundary conditions for life (as we know it) has revealed that scientists don’t yet fully understand the boundary conditions for life on Earth, let alone ET life. They keep finding life where they believe life couldn’t be. And while astrobiologists are working on ways to identify life that is not like Earth life, they can’t yet say they’re ready to know it if they see it.

Extrasolar planet detection is one thing. Obviously astronomers have figured out some good ways to do it. And while this field of research has been under way for  more than two decades, the launch of the Kepler planet-detecting spacecraft in 2009 turbocharged the endeavor, to put it mildly.

Understanding extrasolar planetary habitability is something different, and this field of research is not so far along in its development as planet detection is. And while planet detection is hard, planetary habitability detection is really hard.

As to ET life, the scientific search for evidence of it in our own solar system focuses solely on the possibility of past or present microbial life. It’s a big enough leap, though not unreasonable, to assume that if life began in our solar system it might begin in another planetary system as well. To assume that if life has begun elsewhere, it likely has evolved to a level of complexity that has produced intelligence, as we understand it (which is, in my humble opinion, not very well), is – well, it’s an assumption that I would characterize as a somewhat educated guess, at best.

Of course we should keep looking – for planets, habitability, and life. Our conception of ourselves and our place in the universe has already changed – I think for the better – as a result of these (relatively young) scientific endeavors. I only ask that we keep our expectations tuned to “reasonable” (and remember that the so-called “Drake equation is not an equation”).

 

* Keep in mind, though, that while the fictional Tatooine of “Star Wars” was an inhabited rocky planet, these two new planets are low-density gas giants reported to be close to but not within the assumed habitable zones of their star system.)

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