This process, called accretion, is how everything in the solar system – planets, moons, comets and asteroids – came into being. Telescopes can see young solar systems being born.

For decades, our solar system was thought to have nine planets, with Pluto considered the smallest and farthest. But in 2006, Pluto was officially reclassified as a dwarf planet by the ...

Earth has four seasons, but do other planets in our solar system also have hot summer days and cold winter nights?

How big is Jupiter? What to know about gas giant Jupiter is not only the largest in the solar system, but is so humongous that it's more than twice as massive as the other planets combined.

Stars passing close to the sun could cause planets to collide, including with Earth, or even be ejected as rogue planets, new simulations show.

New research says that Earth could be ejected from our solar system if a passing star was to come close enough.

Most of the visible planets in our solar system are slowly disappearing from the night sky, in what some astronomers call a “planet dry summer” that will last for years.

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 ...

Our solar system may have a ninth planet after all, following the declassification of Pluto nearly two decades ago, researchers say.

Are planets in the solar system that are closer to the Sun older than the ones further away? – Gavriel, age 10, Paducah, Kentucky ...