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 ...

To better understand why the planets have variable compositions ... to the formation of the gas and ice giants in the outer solar system. This first-order model of planetary growth in the solar ...

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