Science & Technology

Scientists Have Found Two Earth-Like Worlds Around a Nearby Star

Scientists have found two new Earth-like planets near one of our closest neighboring stars. Finding these worlds that close to Earth is a good thing because it means we can study them more closely than other exoplanets and find out what life is there. Since there is only 12 light-years from home, forthcoming observatories can check out their atmospheres for oxygen or any other signs of life. And who knows — in some distant time, we may even try communicating with them.

They're Not the Only Ones

Here's the rundown on the two new worlds: they're only a little larger than Earth and orbit their parent star — known as Teegarden's Star — every five days and every 11 days, respectively. That sounds like a super-fast orbit, but they have to stay close to the star for warmth and to maintain liquid water on their surfaces. That's because Teegarden's Star is an M-dwarf, which is a class of star that puts out less energy than the sun. Scientists just announced their discovery in the journal Astronomy and Astrophysics.

The exciting thing is these Earth-like planets are not the only ones so close to home. Right now, scientists define a world as "habitable" if it's a rocky body that could maintain liquid water on its surface. And there are so many potential close-up choices for study right now. Among them are Proxima Centauri b (only four light-years from Earth), Ross 128b (11 light-years), GJ 273b (12 light-years), the two planets at Teegarden's Star (12 light-years), Wolf 1061c (13 light-years), and Kapteyn b (13 light-years).

When a planet is close to Earth, it's easier to learn about its characteristics. It shines brighter in telescopes and any molecules in the atmosphere are easier to see. While very detailed study of these planets may have to wait a few decades until telescope resolution improves, there are some new and forthcoming telescopes that do have exciting potential to show us more.

Getting a Closer Look

NASA launched its Transiting Exoplanet Survey Satellite (TESS) last year to do a full-sky survey for habitable worlds. While this is more like a scout telescope with low resolution, what's exciting is it can pile up planetary finds quickly for other telescopes to verify. And better yet, TESS is optimized to find worlds close to home — not the distant planets that its predecessor Kepler was known for. It's expected that TESS could find dozens of Earth-like worlds before its main mission is finished. If its mission is extended, it might find even more.

Also coming soon is NASA's James Webb Space Telescope, which you can think of as a successor to the venerable Hubble Space Telescope that's been in orbit since 1990. JWST has a busy observation schedule, but one of the things it is designed to do is look at exoplanets that TESS and other telescopes discover. If the planet is big enough — most likely Jupiter-sized — JWST can search its atmosphere and perhaps even take pictures of the planet. Earth-like planets would be more of a challenge due to their small size, but let's not rule anything out until after JWST's launch in 2021.

Then there's the European Extremely Large Telescope (E-ELT), a ground-based observatory under construction in Chile that is supposed to gather 13 times more light than the largest telescopes that observe in visible wavelengths. The website specifically promises that E-ELT will image rocky planets and characterize their atmospheres. So you can imagine that scientists are impatient to see this telescope start operation, which will be in about the year 2025.

So when you think about Teegarden's Star, remember the two worlds there represent a whole new area of science: a whole new time when we get to search for us in the universe. While it's unclear if there's somebody like a Spock or a Yoda or a (shudder) Xenomorph out there, many of us Earthlings are eager to find extraterrestrials in the universe and share our experience with them. So let's keep searching — and hoping we find someone willing to talk to us.

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Learn more about what's out there in Neil DeGrasse Tyson's "Astrophysics for People in a Hurry." We handpick reading recommendations we think you may like. If you choose to make a purchase, Curiosity will get a share of the sale.

Written by Elizabeth Howell June 20, 2019

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