A newly discovered planet called GJ1132b is now the nearest ever Earth-size exoplanet. The “Venus twin” presents our best opportunity to closely study the environment of a rocky alien world, hailed as "arguably the most important planet ever found outside the solar system" by astrophysicist Drake Deming.
GJ1132b is 1.2 times the size of Earth and is located a mere 39 light-years away. To put it in context, “our galaxy spans about 100,000 light-years. So this is definitely a very nearby solar neighborhood star," says lead author Zachory Berta-Thompson of MIT’s Kavli Institute for Astrophysics and Space Research. By comparison, Kepler-452b, so far the most Earth-like exoplanet, is located 1,400 light-years from Earth.
GJ1132b revolves around its star Gliese 1132, a red dwarf. It is only a fifth the size of the Sun and emits less than one percent as much light. This means that the star light does not overwhelm any reflected light from GJ1132b and allows for better studies into the exoplanet’s atmosphere.
The planet also orbits very closely to its star, which allows for more frequent observations using the transit method, where dips in the amount of observed light from a star indicates the presence of a passing planet. GJ1132b takes approximately 1.6 days to complete one orbit around Gliese 1132, which Berta-Thompson says will make it “a favorite target of astronomers for years to come."
As for alien life, GJ1132 receives more radiation from its star because of its proximity, ramping up a surface temperature from 275 to 590 degrees Fahrenheit (135 to 304 Celsius). This makes the planet very similar to Venus in that it's too hot to support known life, yet cool enough to maintain a potential atmosphere.