Scientists have found a planet far out in the cosmos that's close in size and content to Earth -- an astronomical first. But this rocky world is so close to its sun that it's almost certainly too hot ...

Meet Earth’s closest known exo-relative, Kepler 78b. First discovered earlier this year, scientists today confirmed that it’s like Earth in more ways than one—Kepler 78b is rocky, about the same size, ...

CAPE CANAVERAL, Fla. — Scientists have found a planet way out in the cosmos that’s close in size and content to Earth — an astronomical first. But hold off on the travel plans. This rocky world is so ...

We didn’t even discover Pluto (the trans-Neptunian dwarf planet) until 1930. What’s more, we still don’t have a comprehensive map of our own solar system, so it’s no surprise that finding planets ...

This is an archived article and the information in the article may be outdated. Please look at the time stamp on the story to see when it was last updated. A puzzling alien planet is the closest thing ...

Astronomers, always with their heads in the clouds, have discovered “the first Earth-size planet that seems to be made of the same mixture of rock and iron as Earth,” The New York Times reports.

Astronomers have found that a planet discovered earlier this year is, in many ways, Earth’s twin. It’s the smallest exoplanets yet found for which we’ve been able to measure both its size and density.

Kepler-78b is a planet that shouldn't exist. This scorching lava world circles its star every eight and a half hours at a distance of less than one million miles - one of the tightest known orbits.

Hellish home An Earth-sized planet far beyond our Solar System has been found to have a similar mass to our planet, say researchers engaged in the hunt for other habitable worlds. While Kepler-78b is ...