Scientists may have found a way to physically express the saying "like hell on Earth."

Kepler 78b is an exoplanet hundreds of light years away from Earth and resembles our planet in size, the New York Times reported. The key difference is the planet lies to close to its sun, it completes an orbit in eight and half hours and sizzles at 3,500 to 5,000 degrees Fahrenheit.

Earth lies 93 million miles from the sun and completes an orbit in 365.25 days, but Kepler 78b is not even one million miles from its sun, Kepler 78.

As Andrew W. Howard, an astronomer at the University of Hawaii, put it, the surface of Kepler 78b is "well above the temperature where rock melts."

"This is probably one of the most hellish planets that have been discovered yet," said Howard, the lead author of a study published online Wednesday in the journal Nature.

Named after the telescope that spotted it, Kepler 78b was discovered when scientists were sorting through data after the stargazer was retired. The Kepler Telescope broke the second of its four rotating wheels and had to be retired in August. Since, scientists have been dedicated to sifting through the wealth of unexamined data the telescope has produced.

The researchers originally spotted Kepler 78b by noticing the planet's light dim as it passed behind its host star. The onlookers were astonished at how quickly the planet was doing so.

"It's the first really well measured Earthlike composition for a rocky extrasolar planet," said L. Drake Deming, a professor of astronomy at the University of Maryland who was not involved in the study. "You can reasonably conclude from that that it's not rare, because you've found it pretty easily."

Dimitar D. Sasselov, a professor of astronomy at Harvard and member of a separate, but related study, said the next step is to determine how Kepler 78b got to where it is. The planet has a very similar makeup to Earth's as well as size.

The scientists have floated several scenarios, but each have been debunked. One possibility is that it was once a gas giant, like Saturn, but was drawn closer to its sun, all its gasses being stripped away, leaving just a rocky core. Sasselov does not think this is likely, but admitted it was the least bad.

"Right now, this scenario doesn't work, either," Dr. Sasselov said. "If you want me to choose out of four bad ones, that's probably the one which seems least so."