Earth-sized world is a mere 39 light-years away
Jonathan Irwin

Earth-sized world is a mere 39 light-years away

Exoplanets may be a dime a dozen these days—nearly 2000 have been confirmed—but one new discovery is causing a frisson of excitement. GJ 1132b, as it is known, looks a bit like home: only 16% bigger in diameter than Earth and about the same density, suggesting a similar rocky crust and iron core. Although it probably has an atmosphere, it is way too hot to support life. But what’s really getting astronomers interested is that it’s a perfect specimen for study. Firstly, GJ 1132b—detected using the MEarth-South telescope array in Chile (pictured)—is only 39 light-years from Earth—a stroll down the street in astronomical terms—researchers report today in Nature. It orbits a star that is less than a quarter the diameter of our sun and shines much more feebly. This means that when the planet passes in front of and dims the star’s light—the most common way of studying exoplanets—it has a much greater impact on the brightness and so yields more information. And, with a close-in orbit providing such a transit once every 1.6 days, GJ 1132b will give astronomers plenty of opportunities for study. All these factors could make this unremarkable system the most studied in the heavens.