Atmosphere discovered on Earth-like exoplanet in our 'galactic backyard' | ABC NEWS

[00:00:00]The search for life beyond Earth has marked a new discovery. Hints of a new atmosphere have been discovered on a rocky Earth-like planet beyond our solar system. The astronomers responsible for the finding think similar planets may have the same signature and are working on finding more. Study [snorts] lead Dr. Colin Cherubim says the planet is similar in size to Earth as well.

[00:00:23]>> This is a really exciting planet. It's called LHS 1140b.

[00:00:28]Uh it's about 70% larger than Earth. So, as far as exoplanets go, it's roughly the same size as Earth. It's relatively nearby. It's in our galactic backyard.

[00:00:39]Um just a mere 49 light-years away. And it's um orbiting a a star called an M dwarf, which is a bit smaller than our sun.

[00:00:49]>> And how did you find it? And how did you work out that it has an atmosphere?

[00:00:56]>> Yeah, so um for my PhD, I was mainly a theorist, actually, and developed a computer model that simulates how exoplanet uh these are planets outside of our solar system, how their atmospheres evolve over time, over billions of years. And um I specifically predicted that this planet would have a helium-dominated escaping atmosphere. Uh which sounds kind of exotic, but um part of my thesis was actually showing that these types of planets might actually be quite common.

[00:01:25]So, to test that prediction with actual observations, I got some time on uh the Magellan Clay Telescope in the the Atacama Desert in Chile. And I basically observed the planet pass in front of its star from our vantage point on Earth.

[00:01:41]And as that starlight filtered through the planet's atmosphere, helium in the atmosphere absorbed very specific wavelengths of light, which showed up as sort of dips in the stellar spectrum, which allowed me to identify the helium in the atmosphere.

[00:01:56]>> Okay. And how high are the chances then that this planet may or has harbored life? How similar are its conditions to those here on Earth?

[00:02:06]>> Well, in astrobiology, uh you know, we call this the n equals one problem. As in terms of predicting, you know, how habitable this planet might be, it's really tough because we only have one proven example of life, right? That's life on Earth. And when we think about life on Earth, we look for kind of three big things when we think about habitability outside of our solar system. We need a planet that's mostly rocky, right? It can't be a gas giant like Jupiter. Uh it has to be the right temperature to support liquid water on its surface, which we know is essential for life on Earth. And it needs an atmosphere to shield that water from escaping the planet and to shield the surface from harmful radiation. And we now know that this planet has all three of those key ingredients. Not to mention, it orbits a star that's relatively quiet, meaning the star doesn't flare too much. It doesn't have too high x-ray radiation. So, this planet is the current best place to look for life outside of our solar system.

[00:03:04]>> And what is it, Colin, about its position in space that that means that could have these three things that could support life?

[00:03:12]>> Well, it really has to do with the position relative to its star, how far away it is from its star because that's going to determine the temperature of the planet. Uh and in this case, the temperature is in what we call um the habitable zone, meaning the temperatures are similar to Earth. And so, uh that allows for liquid water to um exist on the surface. And it also means that it's receiving um ionizing radiation, that's x-rays and ultraviolet, that um are not, you know, what we consider to be too high to um preclude life.

[00:03:47]>> And I understand that you're investigating another planet that you're excited about?

[00:03:53]>> Yes. Um, you know, I didn't know the cat was out of the bag. I'm not sure how you heard about that one. Maybe I spoke to somebody about it.

[00:04:01]But, yeah, that there's there's essentially a what I'd call an LHS 1140b twin, so to speak, that has remarkably similar properties as this planet. It's it's about the same size. It's a bit smaller.

[00:04:15]It orbits a very similar star about the same distance, and I'm super excited to observe it because, you know, as a astrophysicist who's sort of balancing theory and observation, I want to keep testing my predictions, and I'm really hoping LHS 1140b is just the first of many detections to come. But, we don't know. Maybe it's an oddball, and maybe it's the only one.

[00:04:37]>> Well, good luck with your work, and I hope you can keep us updated on what you discover. Colin Cherry, I'm lovely to talk to you. Thank you.

[00:04:45]>> Thanks so much, Rose. It's great to talk to you, too.