The number of planets that orbit the sun depends on what you mean by “planet,” and that’s not so easy to define ...

For decades, we believed there were nine planets in our solar system—until Pluto was reclassified in 2006. But what if ...

All of our solar system’s planets are lining up to parade through the night sky at once. This extraordinary celestial event will see the sky scattered with seven visible planets in what is known ...

Uranus and Neptune are there too, technically, but they don't appear as 'bright planets'," NASA's Preston Dyches explained in a stargazing video guide. Stock illustration of all the solar system's ...

Monroeville Public Library is holding a three-part children’s series on space, where participants learn fun facts about the ...

Scientists believe that two asteroids might be fragments of long-lost "planetary embryos" from the early solar system.

Stargazers will be treated to a rare alignment of seven planets on 28 February when Mercury joins six other planets that are already visible in the night sky. Here's why it matters to scientists.