A New Earth-Sized Planet Is Getting Astronomers Riled Up

It could be a rare opportunity for scientists to study an exoplanet’s atmosphere

A new exoplanet was discovered by telescopes at the Cerro Tololo Inter-American Observatory Roger Ressmeyer/CORBIS

Just 39 light-years away, a rocky planet a little bigger than the Earth orbits a red dwarf star. It’s the closest planet of its kind astronomers have ever discovered and it might be their best chance to study a planet not too different from our own.

The main reason astronomers are so pumped up about this planet is that it’s a great opportunity to study its atmosphere, partly because it's right in our neighborhood, so to speak. Most of the planets that scientists have discovered outside of our solar system are either too far away or orbit a star that is too bright for telescopes to pick up much detail. Luckily, this new planet is three times closer to us than any other Earth-sized exoplanet astronomers have discovered so far.

Yet not only is this planet right around the block, cosmically speaking, but the star it orbits is dim enough that telescopes can examine its atmosphere, Deborah Netburn reports for the L.A. Times. The red dwarf is only one-fifth the size of our sun, which will let astronomers get a good look at the planet without overloading their telescopes.

Although the planet orbits a much smaller star than our own, it’s much closer to the red dwarf, meaning surface temperatures on the planet vary between 278 and 572 degrees Fahrenheit. While such extreme temperatures make it very unlikely for life to survive on the planet, astronomers won’t know for sure until they measure what gases its atmosphere is made of.

By using telescopes to record and measure the wavelengths of light from the planet’s host star as they pass through its atmosphere, Berta-Thompson and his colleagues will be able to figure out what gases exist on the planet, Loren Grush writes for The Verge.

"Basically we want to peer over the shoulder of someone on the planet who is watching the sunset and see what color the sunset is," MIT astronomer Zachory Berta-Thompson, who helped discover the planet, tells Grush.

The planet may be too hot for most lifeforms, but the data astronomers gather from its atmosphere could teach them a lot about exoplanets similar to Earth’s size. Studying the planet could help refine the tools and techniques used to analyze planets like this, which could come in handy if astronomers ever stumble across another nearby Earth-like planet that could be more habitable.

“If this planet still has an atmosphere, then we might find other, cooler planets that also have atmospheres and orbit small stars. We can then imagine interrogating the atmospheres for molecules that come from life,” Berta-Thompson tells Ian Sample for The Guardian.

Until then, this planet is sure to provide astronomers with a wealth of new information about planets outside our solar system.

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