Fun fact about me: Europa is my favorite moon.
Oh, sorry Moon. You’re cool too. It’s just… you don’t have an ocean. Or chaos terrain. Or possible alien life. It’s nothing personal.
Anyway, on Monday I told you that Congress wants NASA to put a robotic lander on the surface of Europa. But the really interesting bit is deep beneath the surface, where the ice turns to liquid water. Is anything alive down there? Any microbes? Maybe fish? What about alien mermaids?
A lander can’t investigate that sort of stuff. At least not directly. But if you’ve ever seen a picture of Europa…
… you’ll notice the surface is covered in dark reddish-colored lines. These lines appear to be cracks. It’s believed that warm water sometimes forces its way to the surface, carrying with it a mix of minerals and possibly other materials from the oceans below. It’s these minerals which cause the reddish discoloration.
So while a lander can’t sample the ocean water directly, it could examine the materials that have been deposited on the surface. Now, if you’ll allow me to switch my science blogger hat for my science fiction writer hat, I’ll tell you exactly what the Europa lander will find.
Salt. Lots of salt. That won’t surprise anyone. It’s been long assumed that Europa’s ocean is much saltier than the oceans here on Earth. It must be; otherwise the ocean would freeze.
The lander will also detect other minerals as well. And amino acids. That’ll raise some eyebrows, but amino acids aren’t that uncommon. We’ve found them on other planets and we’ve found spectrographic evidence of them all across space. As I reported in last week’s Molecular Monday post, there are literally hundreds or perhaps thousands of different kinds of amino acids in our universe.
That will make headlines. No, it’s not the same 21 amino acids coded for by human DNA, but this cannot be a coincidence. What natural phenomenon, other than life, could produce such a select few amino acids in such large quantities?
But wait, there’s more. These 21 amino acids have something in common. They have the same chirality. And that’s the part where the entire scientific community freaks out.
Tune in for Friday’s edition of Sciency Words to find out what the heck chirality is and why it’s so important in the search for alien life.
P.S.: My second favorite moon is Titan, followed by Io, Miranda, and Triton. Oh, and Naiad! I love Naiad. But Earth’s Moon totally makes in my top ten. Probably.
Planet Pailly 
Interesting. On salt, I thought the thinking was that geological activity caused by gravitational tidal forces from Jupiter was why the oceans don’t freeze. Or is that not quite enough to pull it off? If high salinity is also required, it seems like an additional requirement of the theory that might make it less likely.
If I recall correctly, amino acids have also been found in meteorites, although I’m sure it’s from the broad swath of non-biologically occurring ones rather than the limited selection that life on Earth generates.
LikeLiked by 1 person
As I recall, our current models of tidal forces on Europa don’t generate quite enough heat to account for the global ocean Europa appears to have. So high salinity is assumed to be part of the equation. There are extremophiles that can tolerate that level of saltiness, so this shouldn’t rule out the possibility of Europan life (though I agree it makes it seem less likely).
As my amino acid research continues, I’ll be visiting some of those asteroids. There’s an idea out there that life began in asteroids and was seeded on Earth later. That’s definitely something I want to know more about.
LikeLiked by 1 person
I wasn’t even thinking about any difficulties it might offer to life (although now that you mention it, I suppose it would), just that the requirement for high levels of salt might make the ocean’s existence itself less probable.
If we found that life began on asteroids, I think we could safely conclude that it permeates the universe. Of course, virtually all of it would be microscopic life, but still, that would be a major discovery.
LikeLiked by 1 person
Oh I see. I think there is still some doubt about whether or not Europa’s ocean exists, but that based on observations (the moon’s density, libration, etc), it sure looks like an ocean is there. The trouble then is explaining how all that water stays liquid.
LikeLiked by 1 person
Ah, good point. I forgot that there were other observations that made a liquid ocean likely.
LikeLiked by 1 person
I would like to point out that Luna does have possible alien life. I’ve heard that microbes may have been left behind from the moon landings, and if they found a way to survive and reproduce, any microbes born on the moon would be alien.
LikeLiked by 1 person
True. If I remember correctly, we accidentally contaminated the Moon with the bacteria that causes strep throat.
LikeLike