The number of planets that orbit the sun depends on what you mean by “planet,” and that’s not so easy to define ...

The building blocks of life could have been delivered to Ceres by one or more space rocks from the outer asteroid belt.

Skywatchers: A six-planet alignment peaks this week as Mars, Jupiter, Uranus, Neptune, Venus, and Saturn come together for ...

The dwarf planet is a bizarre ... in smaller quantities -- other elements form the basic building blocks of all life. In recent years, researchers have found such molecules at great distances ...