Europa’s Cold Spot

I still have a ton of research reading to catch up on from 2018.  This weekend, I read a paper about Europa.  I wasn’t sure at first why this was on my to-be-read list, but by the end I knew why this one had caught my attention.

Europa is one of the icy moons of Jupiter.  It’s often listed as one of the most likely places in the Solar System where we might find alien life.  That’s because there’s evidence of a vast ocean of liquid water sloshing around beneath Europa’s icy crust.

Maybe someday we’ll be able to drop a little robo-submarine into that ocean and see if anything’s swimming around down there. But in the meantime, we’re really only able to explore Europa’s surface.  And as you can see in the highly technical diagram below, no matter where you go on Europa’s surface, it’s cold.  But in one specific region, Europa gets really cold.

Or at least, that one region appears to be extra cold.  This is a case where it’s important to understand how we get our data. We’re really measuring Europa’s thermal emissions, the amount of heat that gets radiated out into space. So that cold spot may represent one of two things:

• Either that region absorbs less sunlight than the rest of Europa, and so it never heats up in the first place…
• Or that region does a better job trapping the heat it absorbs from the sun, and so we detect less heat escaping back into space.

Either way, something weird is happening. Unfortunately, our previous missions to the Jupiter system did not provide us any useful photos of that one specific spot on Europa’s surface.  Our current Juptier mission, Juno, is unable to approach Europa at all, so that’s no help.

So we can’t match this anomalous cold spot to a visible surface feature.  However, the authors of the paper I read did suggest that this could be a sign of recent geological activity—the formation of chaos terrain, perhaps.

And if that’s true, we might (might!) find the waters of Europa’s subsurface ocean seeping up to the moon’s surface.  Maybe there’s fresh organic material seeping up onto the surface too.  Maybe.

Maybe.

Could be worth checking out, though.  Don’t you think?