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, ...

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.

When you purchase through links on our site, we may earn an affiliate commission. Here’s how it works. Breaking space news, the latest updates on rocket launches, skywatching events and more! You are ...

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 ...

A puzzling alien planet is the closest thing to an Earth twin in size and composition known beyond our solar system, though it's far too hot to support life, scientists say. The exoplanet Kepler-78b, ...

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.

Imagine waking up every day to a new year. That’s exactly what happens on a Earth-size fireball of a planet 700 light-years away, which orbits its star in just 8.5 hours. The newly discovered planet, ...

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.