Monday, February 7, 2011

1,200 exoplanets. Any neighbors?

Image by NASA
Take a walk with me, to the scientific fringe. Let's talk briefly about aliens.

I don't mean alien abductions, or alien autopsies, or gray men with bulbous skulls, and eyes that seem far too big to fit two inside of a head (have you ever noticed that?). I'm talking about something more exciting. Aliens that look nothing like humans. Aliens that haven't evolved under our gravity, or our sun. Real aliens.

Before 1992, many believed that our solar system contained the only nine planets in the universe (there were nine back then!). It wasn't a matter of whether this was the only solar system that contained life, but whether it was the only solar system at all. If it were the only solar system, the chance of our existence would be astronomically more astronomically unlikely than it seems now. This specialness would mesh well with the worldview (universeview) of those that wrote the Bible.

But, in 1992, the first exoplanet (planet outside of our solar system) was discovered and confirmed, and we've been looking for more ever since. There are a few different methods that scientists use to detect the planets, because we can't see them the way we see a car down the street, even with powerful telescopes. Astronomers look at the bahavior of stars to determine if there is anything orbiting it, and then determine that thing's properties. That's as far as I'll go here, but feel free to Google it if you're interested.

After the first exoplanet was confirmed, it became a question of whether there existed habitable exoplanets. After all, what good is a molten world, or a gas giant? They're also looking for the possibility of liquid water.

There are plenty of scientists that believe life can't exist without conditions similar to what we have here on Earth, but I personally think that's sort of ridiculous. You can't draw conclusions about life-hosting planets when your sample size is one, after all. How thirsty do you have to be before you start assuming that all life in the universe wants a glass of water? All we can safely assume, I think, is that life requires energy. As has been proven on Earth, though, life-giving energy can be radiated from the center of the planet as well as from outside.

A wet Mars.
Image by Michael Carroll.
That aside, in the summer of 2008, we found out that there is frozen water on Mars, right next door. Enough that, at some point in the past, Mars just might (also might not) have been covered in oceans. The artists' depictions of the red planet with blue seas are exciting to look at.

When some scientists talk about life on other planets, they make sure to mention they're talking about microbial life. I have to say, right now, that this makes no sense to me. I think they say this to sound reasonable, and restrained, (unlike the news, or the lay population). In this gritty, dusty place we call reality, though, it seems unlikely that microbial life would sit around and stay microbial for a million years, just because a few scientists are trying to sound reasonable back on this little blue marble.

In 2009, the Kepler telescope was launched specifically to look for earth-like planets orbiting distant stars.  Well, on February 2, 2011, scientists gave us an analysis of data gathered during five months in '09, and it was big news. 1,200 new planets! About five of them are potentially Earthlike, and at least 54 of them in "habitable orbits." Some of these might be false alarms, but not 1,200 of them.

So, planets aren't as rare as we thought, water isn't as rare as we thought, Earthlike planets aren't as rare as we thought. In my mind, these progressive discoveries are like a road. One that leads to a destination. I can't say for sure what the destination is, but I'll bet all of you twenty dollars that it's life outside of our solar system. My unscientific reasoning says that we just seem to be moving in that direction so fast. And if life as we (don't) know it is out there, even in one place, then it's not a coincidence. Life is too complex to be a coincidence twice. So if there's one more, there's a million more.
True aliens would not look attractive to humans

If you've read, or watched, science fiction, you might have some funny ideas about alien life.  Of course, this is necessary.  The organisms and technologies found on alien worlds in sci-fi are based, almost entirely, on organisms and technologies really found on Earth. I don't think you can (or should) write a story that absolutely nobody can relate to.

Consider these three (of many) assumptions we make in our science fiction, and how they effect our expectations of reality:
  • That a dominant species will be humanoid:  We even make our cartoon animals humanoid. There is no reason for this to be true, as far as I know. This is one of the (several) reasons I question the existence of the "greys" or the "reptilians." The most inhuman aliens we make tend to look like insects. Our imagination will never beat that of natural selection.
  • That other worlds will have a dominant species, at all: The dominant species may very well be an anomaly specific to Earth. One primate got a bigger brain, and started bending the rest of the planet to its will. I don't see this as inevitable. Think about it this way: If humans had never come about, what would the dominant species on Earth be? Sharks? Bears? Orangutans? Of course not. (As a side note, I always hear that dinosaurs once ruled the earth.  Of course they didn't. They just lived here.)
  • A division between plants and animals: Our most basic distinction between organisms is that between the plant and the animal (and the fungus, of course). This only seems so natural to us because it's what we were built (so to speak) around. What are some alternatives? I have no idea. That's the point.

And we can't ignore the very real possibility that my metaphorical road may end with no life on other planets. Our own little Earth may be the specialest planet ever, like we've been saying since we started speaking. It's not good for our sense of wonder, but it's great for our ego. And it would also mean that, when we eventually invent the Starship Enterprise, and start settling these distant worlds, we won't have a repeat of manifest destiny, treating the natives in ways that me may, someday, regret.

Thanks for reading.

I read The Crowded Universe, by Alan Boss, last year. It's a detailed history of the scientific search for Earthlike planets, and the struggles along the way, written in a way that's accessible to the lay person. It also includes an interesting account of the Pluto story, how it was discovered, and then, after much conflict, eventually castrated of its planethood.

No comments:

Post a Comment