I’m not gonna lie. I was worried. There are a lot of steps that must be taken if we are to find life on another planet, if we are to know that life is possible on any planet other than Earth. Last week I learned that one critical step had just been crossed.

We’re pretty sure that life requires planets. It would just be too hard for it form floating freely in space. Thanks to amazing new telescope technologies we now know that planets are everywhere. Every star you see at night hosts a family of worlds. We also think life will require not just planets but “rocky planets” i.e. planets with surfaces and a place to stand (or swim if those surfaces are covered in oceans). This is in comparison to gaseous planets like Jupiter or Saturn. Thanks again to that amazing telescope tech, we also know that rocky planets are pretty common.

So, planets … check. Rocky planets… check. What is the next big step? The answer is atmospheres on rocky planets.

You are never going to get life on a bare rock exposed to the vacuum of space. To get life going you’ll need a planetary atmosphere made of gases that can help keep the planet at a nice stable temperature (preferably one where liquid water can exist) and protect the surface from harmful radiation from the parent star. There’s a lot more than atmospheres can of for life so it’s a pretty good bet that without them a planet will be sterile.

For a while now astronomers have been searching for rocky planets with atmospheres. And for a while now they were coming up empty. It was actually getting kind of depressing. The Trappist-1 system was a nice example of this trend. Composed of 7 worlds on tight orbits around their small star, astronomers have been using the JWST to progressively move outward and look for atmospheres on one Trappist world after the other. Each paper announcing no detection made all us worry: “Maybe rocky planets with atmospheres are really rare”. That would suck for the search for life.

Happily, that looks like that may not the case.

Last week scientists announced the discovery of an atmosphere around the rocky planet LHS 1140 b (note to self: we need better names for these worlds). The planet was a “super Earth” meaning it was bigger and more massive than our world, but it is definitely rocky. Even better yet it’s in the parent star’s habitable zone meaning liquid water could exist on the LHS 1140 b’ surface. An atmosphere and the possibility of liquid water… Holey Moley that is a recipe for biology.

There are cool details here which I won’t go into but, basically, the atmosphere was discovered by seeing a “wind” of helium atoms being blown off the planet. I get psyched about this part because our research group at the UR produced some of the first 3-D supercomputer models of such planetary winds.

But anyhoo…if you are a fan of alien life then this is really, really exciting news. Science moves slowly; it moves steadily but man it does move.

Onward!

— Adam Frank 🚀