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

Stargazers will be treated to a dazzling six-planet "alignment" this January.

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

Stargazers will be treated to a rare seven-planet alignment in February. This is what scientists hope to learn.

Six planets are parading across the sky, appearing as some of the night's brightest stars. A few easy tips can help you ...

Mars, Venus, Jupiter and Saturn should be visible to the naked eye, but get a telescope and you can spot Neptune and Uranus.

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

Planetary alignments aren't rare, but they can be when they involve six of the eight planets in our solar system. Look for a planetary parade that includes Mars, Jupiter, Uranus, Neptune ...

Timing: Dusk after sunset, but before 9 p.m. local time There are eight planets in our solar system and one dwarf planet (Pluto). Because we live on Earth, the most we could see is a maximum of ...

Timing: Dusk after sunset, but before 9 p.m. local time There are eight planets in our solar system and one dwarf planet (Pluto). Because we live on Earth, the most we could see is a maximum of seven ...

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.