A low-density, puffy planet orbiting relatively far from a young star in a nearly perpendicular orbit. What's going on?

A new study has proposed the existence of Planet Y, an alternative Planet Nine candidate that is smaller and closer to Earth ...

For almost a decade, astronomers have been searching for a ninth planet in the solar system. Recently, new evidence of ...

We actually know very little about what's going on inside Uranus and Neptune, causing researchers to propose that these ...

There are a couple of ways that scientists can date planets, so which planets formed first in our solar system?

Astronomers believe they may have uncovered evidence of a hidden Earth -size planet lurking in the outer solar system. Dubbed “Planet Y”, the proposed world could be nearly twice as close to Earth as ...