It doesn’t take a Carl Sagan-style tear-jerker to realize how unique and awesome our planet is (although it never hurts), but as astronomers ramp up the search for exoplanets orbiting other stars it’s becoming clear that places as chill as Earth are even more rare than anyone thought
By Daniel Oberhaus | MOTHERBOARD
To find other exoplanets that might be like Earth, astronomers tune their telescopes to the ‘Goldilocks region’ around a star. This is the habitable zone that is far enough away from the star so the planet’s surface isn’t scorched like Venus, but close enough that it isn’t freezing like Mars. Astronomers have found over 40 exoplanets in Goldilocks regions to date (a small fraction of the thousands of exoplanets that have been discovered), but according to new research coming out of Yale, this doesn’t necessarily tell us anything about their ability to support life.
As detailed in a paper published Friday in Science Advances, there is a second Goldilocks factor that needs to be taken into consideration when attempting to determine a planet’s habitability: its internal temperature during formation.
Prior to the new study, it was thought that planets had the ability to self-regulate their internal temperatures via a process called mantle convection, or the slow movement of Earth’s solid mantle as a result of the heat from the core of the planet. Regardless of the planet’s internal temperature during formation, the shifting of underground rock as it was heated or cooled would regulate the planet’s temperature until it was just right.