Star Trek shouldn’t be anyone’s idea of rigorous scientific accuracy — unless, as Bad Astronomer and science writer Phil Plait put it, you were raised on Doctor Who, in which case Trek looks like a documentary. But that’s a terrifyingly low bar, and so Plait and NASA engineer Bobak Ferdowsi spent an hour at the Star Trek: Mission New York event Saturday, considering what alien life could look like both in our solar system and beyond. The short answer is that there are lots of stable, peaceful places, including elsewhere in our own solar system, where life could evolve, but intelligent species like humanity might not arise unless things get a little violent.
But let’s back up and consider life at its most basic and most common. The recent explosion in exoplanet discoveries — Plait said it’s now very possible there are more planets than stars in the night sky — suggests the universe could well be teeming with life just like in the Star Trek universe, except those aliens would overwhelming be of the microbe variety. But then, that’s true of life on Earth: Even ignoring just how massively our microscopic cousins outnumber us, microbes ruled the planet alone for billions of years before humans showed up. As Plait put it, starship captains would probably spend most of their time not making first contact with humanoid aliens but charting an endless succession of foul-smelling, yeast-covered planets.
That’s assuming Earth-like planets are actually the best place to be looking for life, be it intelligent or microbial. And even in our solar system, if you leave aside the little detail that we know there actually is life on Earth, the statistically most likely spot to find life might not be here but in the moons of Jupiter and Saturn, like Europa and Enceladus.
“Not only have we been kind of boneheaded in not looking to other types of places for liquid water, they probably outnumber Earth-like planets,” Plait said. “Because water is incredibly abundant in the universe, we know there are big planets that probably have moons, and you don’t even need a star.” The gravitational force of those gas giants can keep liquid water churning below the surface of their frozen moons, and they could end up having billions more years for life to evolve than Earth did.
“If the Sun went out, and it will someday,” Plait continued, “Saturn and Enceladus won’t care. Enceladus will still orbit Saturn and it’ll still be squeezed and it’ll still give off these geysers or still have liquid water below the surface.”
“It’ll actually be better for them,” Ferdowsi added, “because they’ll get a bunch of new chemicals deposited on the surface and some of them might have interesting interactions.”
“These moons will have billions more years of habitability than we would,” Plait said. “So it strikes me that if you’re looking out into the universe for life, Earth-like planets aren’t the way to go. These moons have had a lot longer and far more stable environments.”
But while gas giants’ moons might have the best shot at developing life in general, intelligent life might need the more volatile conditions we get on a planet like Earth.
“Though there’s some argument that you need violence, you need tectonic action, you need earthquakes and volcanoes and the occasional asteroid impact to mix things up a bit to develop intelligence,” Plait said. “Because if things are very calm and peaceful, you get sort of a microscopic version of Wall-E, where everyone is just sitting around in their chairs watching TV all the time, converting sunlight into oxygen, that’s all they do.”