Space. It's really, really big. How big is it? Well, according to astronomers, the observable universe is around 92 billion light-years in diameter, but that's all we can see (hence the word ...

In a surprising twist to our understanding of exoplanetary systems, astronomers have uncovered three Earth-sized planets ...

Every planet in our solar system is essentially round. But out in the universe, are there any planets that aren't spherical? Technically, planets are round, by definition; they need to have enough ...

Far beyond the eight familiar planets in our solar system, countless bizarre and extreme worlds await discovery — and some have already been found. Thanks to rapidly advancing telescope technology, ...

Astronomers poring over four years of data from NASA’s Kepler spacecraft have discovered a star that’s 11.2 billion years old and has at least five Earth-size planets. “We thus show that Earth-size ...

Our search for exoplanets is focused on Milky Way stars. It's been successful, with more than 6,000 detected so far.

There’s a new place to look for life in the universe. Astronomers announced Wednesday the discovery of an Earth-size planet around a small red star in our corner of the galaxy. The planet could hold ...

For centuries our solar system was the only planetary system known to humans. We had no proof other worlds existed beyond those in our own cosmic backyard, and we imagined that if other planetary ...

As telescopes have become more powerful, it’s turned out our solar system is not the only game in town: There are millions of ...

Learn how exoplanets are discovered, what makes planets beyond our solar system unique, and how they drive the ongoing search for alien life in the universe.

A star about 600 light-years away is giving astronomers a front-row view to the environments in which rocky planets like Earth form around the most abundant stars in the universe. Called ISO-ChaI 147, ...