Astronomers find evidence of a possible ninth planet beyond Neptune, reigniting the debate about the formation of the Solar ...

Today, it’s believed that Jupiter and Saturn, the largest planets, were the first to fully form, both within a few million ...

Discover the order of planets in the solar system. From Mercury to Neptune, explore our solar system and learn more about our cosmic home. The solar system is our cosmic neighborhood, made up of ...

Jupiter, roughly 562 million miles from Earth today, has nearly 100 moons. But Batygin and his collaborator Fred Adams' ...

Pluto was reclassified as a dwarf planet in 2006. Our solar system may have a ninth planet after all, researchers say. The possibility that an additional planet may be hidden far into the solar ...

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 ...

Check out the rest of the series. If you were born in the last century you might have memorized that there were nine planets in our solar system, as heard in the famous Schoolhouse Rock!

Are planets in the solar system that are closer to the Sun older than the ones further away? – Gavriel, age 10, Paducah, Kentucky A cloud of collapsing gas created our Sun, the first thing to ...