Mars is the fourth planet from the sun and has a distinct rusty red appearance and two unusual moons. The Red Planet is a ...

The rusty world is full of mysteries—and some of the solar system's most extreme geology. Learn more about Earth's smaller, colder neighbor.

Earth, our home planet, is a world unlike any other. The third planet from the sun, Earth is the only place in the known universe confirmed to host life. With a radius of 3,959 miles, Earth is the ...

How far it is from the sun: 886 million miles (1.4 billion kilometers), on average How big it is: 72,400 miles (116,500 km) across, or almost 10 times the size of Earth. How many moons it has: At ...

Ah, Earth. We may not think about our planet on a day-to-day basis, but the world we live in is a pretty interesting place. The third rock from the Sun—and to this day, the only one with known ...

The moon is our constant companion and the only natural object that always orbits Earth. It's about four times smaller than Earth and its gravity is much weaker, which is why astronauts bounce around ...