She mapped our solar system's "alternate fate" had it housed an extra ... formation of a planet that is at least twice the size of Earth's mass—a super-Earth—instead of an asteroid belt.

Keep your eyes on the sky. Six planets in our solar system are coming into alignment and will be visible from Earth. AccuWeather says Saturn, Venus, Neptune, Uranus, Jupiter and Mars will be ...

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 ...

Asteroids that orbit close to the Earth inevitably cause us some anxiety due to the even remote possibility of a collision. But their proximity also offers ample opportunities to learn more about the ...