The final frontier
The possibility of discovering a planet that is small, cool, rocky, orbiting a sunlike star and able to host life — an Earth twin, in other words — has made the search for planets outside of our solar system, or exoplanets, one of the hottest research areas in physical science. This three-part series explores MIT researchers’ roles in the quest to find an Earth twin and the effort to make sense of the 500 exoplanets that have been discovered since 1995.Although Gliese 581g is the most Earthlike planet to be discovered to date, it’s unclear whether the planet is habitable. Just because the planet is relatively similar in mass to Earth doesn’t mean it can host life. Although Earth and Venus are about the same mass and size, the surface of Venus is too unbearably hot for life to...