Everyone knows about the Solar System, and the planets that make it up. They’re in space, orbiting the Sun, in an order we all at least used to be able to recite. But it was not always so.

With a radius of 3,959 miles, Earth is the fifth largest planet in our solar system, and it's the only one known for sure to have liquid water on its surface. Earth is also unique in terms of ...

Narrator: As the solar system grew, four rocky planets: Mercury, Venus, Earth and Mars, were created closest to the Sun. Made of rocks and metals, they have solid surfaces and a central core of ...

Comets, often described as the solar system's "dirty snowballs," are icy bodies made of rock, dust and ices. These relics of ...

Test your knowledge on our solar system, from the biggest and smallest planets to the behemoth mountain on Mars. When you purchase through links on our site, we may earn an affiliate commission.