Astronomers observe for the first time the actual motion of spirals in a protoplanetary disk, revealing gravitational ...

More planets are changing directions. First, Mercury circled retrograde. This week, Mars is reversing course and Neptune starts spinning forward again. Going retrograde and stationing direct are the ...

Shedding light on the gravity of the situation. Most people do not realize that many of the stars and heavenly bodies they see in the sky no longer exist. In fact, many have ceased to exist for ...

When you look at the solar system, you might notice that the planets' orbits are tilted, and oddities in the protoplanetary disk might be to blame.

The next several weeks will give skywatchers a chance to see many planets at once. Shimpei Yamashita via Getty Images The night sky will offer stargazers a special sight for the next several weeks: ...

What just happened? A newly identified object spotted in two infrared sky surveys may be the most substantial evidence for the elusive Planet Nine – a potential Neptune-sized world orbiting hundreds ...

If the object really is Planet Nine, it would be larger than Neptune and exist 700 times further from the sun than Earth. The best candidate yet for the elusive Planet Nine has been spotted in two ...

Is there a massive undiscovered planet on the outer reaches of the solar system? The idea has been around since before the discovery of Pluto in the 1930s. Labeled as planet X, prominent astronomers ...