Kepler 78b is Just Like Earth, Except it's Scorching Hot

Scientists scanning the skies have located a small exoplanet with Earth-like characteristics except for one detail: it's scorching hot.

MIT researchers analyzing date from NASA's Kepler Telescope found that exoplanet Kepler 78b is incredibly similar to Earth in many ways despite being 400 light-years away. For starters, the planet is only 1.7 times the mass of Earth, and has a density of 5.3 grams per cubic inch (Earth's is 5.5 grams per cubic inch). Judging from the data, the exoplanet is also composed of rock and iron.

"It's Earth-like in the sense that it's about the same size and mass, but of course it's extremely unlike the Earth in that it's at least 2,000 degrees hotter," says team member Josh Winn, an associate professor of physics at MIT. "It's a step along the way of studying truly Earth-like planets."

The planet's blazing temperatures can be attributed to its close proximity to its parent star. Kepler 78b maintains an incredibly tight orbit, circling its star in just 8 1/2 hours. The planet's short orbit has scientists excited, for it gives them an unprecedented look at an exoplanet's behavior. Such quick passes mean multiple data sets in a relatively short amount of time compared to other planets. Still, it's not a walk in the park.

"The star is moving at the same speed as when we walk to school or go grocery shopping," MIT graduate student Roberto Sanchis-Ojeda said. "The difference is that this star is 400 light-years away, so imagine how complicated it is to measure such speeds from so far away."

Kepler 78b is the smallest exoplanet for which the size and mass are known.

You can read the full published study detailing the findings in the journal Nature.