On the evenings of Jan. 17 and 18, the planets will appear virtually side by side, in what's called a “planetary conjunction.

The enormous visitor to our solar system may have been about 8 times the mass of Jupiter, and come nearly as close to the sun ...

Saturn’s rings, imaged here by NASA’s Cassini orbiter, are one of the solar system’s most reliably spectacular sights. But ...

Venus, Saturn, Jupiter and Mars are all visible to the naked eye just after the sun goes down. Neptune and Uranus can also be spotted, but binoculars or a telescope are needed for that.

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

NASA’s Voyager mission completed humankind’s first close-up exploration of the four giant outer planets of our solar system.

Space isn’t lawless, but the agreements governing it don’t cover everything nations will have to grapple with as they develop ...

Twenty years ago, the Huygens probe achieved humanity's first landing on a moon in the outer solar system when it touched down on Titan.

Chorus waves, which affect the safety of astronauts and satellites, have been found in a place where their existence was ...