Scientists this week announced the discovery of a new planet, roughly 400 lightyears away, that they are calling Kepler 78b. Kepler is rare in that it contains similar features to that of the planet Earth; it is composed of a mixture of rock and iron, and it orbits a sun.
There's just one slight catch. Whereas the planet we live on is 93 million miles away from the sun it orbits, Kepler 78b is less that a million from its sun. That makes it hot. Really hot, in fact. As in, 3,500 to 5,000 degrees on the surface. Plus, because of its closeness to the sun, a year on Kepler 78b would take around eight and a half hours.
The exoplanet was first discovered by the Kepler spacecraft, and then studied independently by two separate teams that, according to The New York Times, came up with very similar measurements. They determined that "the density of Kepler 78b is 0.2 pounds per cubic inch, the same as Earth’s, suggesting that the two planets’ makeup is very similar — an iron core with rocky, if melted, outer layers."
The biggest mystery about the exoplanet is how it got to its current location. It couldn't have formed as close to the star as it is now (the star would have been much larger around the time it formed, but planets cannot form inside of stars) and there is no obvious solution to how it was transported to its current orbit.
Scientists don't have much time to gather data about the Earth-like sphere though. Its star's gravitational pull is expected to tear Kepler 78b apart in just three billion years time.