Hello, friends! Let’s talk about aliens!
If we want to find alien life, where should we look? Well, if money were no object, I’d say we should look anywhere and everywhere we can. Phosphorous on Venus? Could be aliens. Let’s check it out. Melty zones beneath the surface of Pluto? Let’s check that out too. Ariel? Dione? Ceres? Let’s check them all for signs of alien life!
But money is an object. We simply don’t have the resources to explore all of these places. Space exploration is expensive. Space exploration will always be expensive so long as we’re stuck using rocket-based propulsion. The Tsiolkovsky rocket equation makes it so.
Whenever you’re working within a restrictive budget, you need to think strategically. With that in mind, astrobiologists (scientists who specialize in the search for alien organisms) have focused their efforts on four worlds within our Solar System. Their names are Mars, Europa (moon of Jupiter), Enceladus (moon of Saturn), and Titan (another moon of Saturn).
This month, I’m going to take you on a deep dive (no pun intended) into Europa. In my opinion, of the four worlds I just listed, Europa is the #1 most likely place for alien life to be found. I don’t mean to denigrate Mars, Enceladus, or Titan. There are good reasons to think we might find life in those places, too. But there are also good reasons to think we might not.
- Mars: Life may have existed on Mars once, long ago. But then the Martian oceans dried up. We’re unlikely to find anything there now except, perhaps, fossils.
- Enceladus: Enceladus’s age is disputed. She may be only a few hundred million years old, in which case she may be too young to have developed life.
- Titan: If you want to believe in life on Titan, you have to get a little imaginative about how Titanian biochemistry would work.
Europa doesn’t have those issues. Unlike Mars, Europa has an ocean of liquid water right now, in modern times. Unlike Enceladus, Europa’s age is not disputed; she’s definitely old enough for life. And unlike Titan, Europa doesn’t require us to get imaginative about biochemistry. The same carbon-based/water-based biochemistry we use here on Earth would work just as well for the Europans.
There are still good reasons to search for aliens on Mars, Enceladus, and Titan. Finding fossils on Mars would be super exciting! Enceladus’s age is, as I said, in dispute, with some estimates suggesting she’s very young, but others telling us she’s plenty old. And while life on Titan would be very different than life on Earth, scientists don’t have to imagine too hard to find plausible ways for Titanian biochemistry to work.
But if I were a gambler, I’d put my money on Europa. And if I were in charge of NASA’s budget, I’d invest heavily in Europa research and Europa missions. Europa just seems like the safest bet to me, if we want to find alien life. And in the coming month, I plan to go into more detail about why I feel that way.
WANT TO LEARN MORE?
If you’re interested in learning more about the Tsiolkovsky Rocket Equation, you may enjoy this article from NASA called “The Tyranny of the Rocket Equation” (because NASA is the American space agency, and anything Americans don’t like is tyranny).
As for astrobiology, I highly recommend All These Worlds Are Yours: The Scientific Search for Alien Life, by Jon Willis. Willis frames the search for alien life just as I did in this post: alien life could be anywhere, but you only have a limited budget to use to find it. So how would you spend that money?