When I was a kid, there were nine planets. Now we know of thousands! But that includes exoplanets, alien worlds that orbit alien suns. Only eight planets call our solar system home. Or there might ...

Astronomers are closing in on one of the most tantalizing possibilities in planetary science, evidence that a previously unknown world may be lurking in the outer reaches of the solar system. The ...

Add Yahoo as a preferred source to see more of our stories on Google. The Oort Cloud, an expanse of icy bodies in the far reaches of our solar system, is shown here in a scene from "Encounters in the ...

Colonizing the solar system is not a single plan with a single outcome. Different goals lead to very different strategies, from mining asteroids to terraforming planets to building vast orbital ...

When you purchase through links on our site, we may earn an affiliate commission. Here’s how it works. Our solar system has been around for 4.6 billion years. While that sounds like a long time, it's ...

The shocking findings were part of a recent study in which astronomers effectively peered back in time to discover what Jupiter was like in its early years. Jupiter is not only the largest in the ...