There are 8 planets in our solar system. The planets orbit the Sun in elliptical trajectories, and they are all different in size, composition, temperature, and characteristics. The planets can be ...

An object eight times the mass of Jupiter may have swooped around the sun, coming superclose to Mars' present-day orbit before shoving four of the solar system's planets onto a different course. When ...

PASADENA, Calif.–The International Astronomical Union (IAU) today downgraded the status of Pluto to that of a “dwarf planet,” a designation that will also be applied to the spherical body discovered ...

When I was a kid, there were nine planets. Now we know of thousands! But that includes exoplanets, alien worlds that orbit alien suns. Only eight planets call our solar system home. Or there might ...