One of the dire frustrations of studying planets around other stars (and, really, any astronomical object) is their distance from Earth, which makes it onerous or impossible to get many basic details about them. Exoplanets are doubly frustrating because any light they emit (light that would give hints about what's happening on the surface) is often overwhelmed by the light of the parent star.
But the new planet, called GJ 1132b, is only a cosmic stone's throw from Earth, orbiting a fairly dim star, and appears to be a rocky world with an atmosphere. And while its surface temperature indicates that it may have more in common with Venus than Earth, it is so perfectly primed for Earth-based studying, that astrophysicist Drake Deming hailed it as "arguably the most important planet ever found outside the solar system."
The significance of this new world derives from several factors. The first of those factors is its size—only 1.2 times the mass of Earth—and second is its proximity—only 39 light-years from our sun. These factors earned it the title "closest Earth-sized exoplanet yet discovered.
Our galaxy spans about 100,000 light-years. So this is definitely a very nearby solar neighborhood star.
"Our ultimate goal is to find a twin Earth, but along the way we’ve found a twin Venus," said astronomer David Charbonneau of the Harvard-Smithsonian Center for Astrophysics, in a statement. "We suspect it will have a Venus-like atmosphere too, and if it does we can’t wait to get a whiff."
While this is too high for life (as we know it) to survive, it is cool enough to potentially maintain an atmosphere. CJ 1132b is "significantly cooler than any other exoplanet confirmed to be rocky. In comparison, well-known worlds such as CoRoT-7b and Kepler-10b possess scorching temperatures of 2,000 degrees Fahrenheit or more." At those temperatures, atmospheres similar to the one on Earth or Venus rarely survive.
"If we find this pretty hot planet has managed to hang onto its atmosphere over the billions of years it’s been around, that bodes well for the long-term goal of studying cooler planets that could have life," Berta-Thompson said. "We finally have a target to point our telescopes at, and can dig much deeper into the workings of a rocky exoplanet, and what makes it tick."
Perhaps, among this population of planets, scientists will find an alien world with the right setup to support life. GJ 1132b could be an important step toward that discovery.