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

Six of the planets in our solar system will line up, in what is sometimes called a 'planetary parade'. They include Venus, ...

Though the planets are always “aligned,” seeing more than four in the sky is more uncommon. February’s lineup is a chance to ...

An object eight times the mass of Jupiter may have swooped around the sun, coming superclose to Mars' present-day orbit ...