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

Planet demographics reveal a puzzling lack of worlds in a certain size range throughout the galaxy F or centuries our solar system was the only planetary system known to humans. We had no proof other ...

More pocked with craters than any other object in our solar system, Jupiter's outermost and second-biggest Galilean moon, Callisto, appears geologically unremarkable. In the 1990s, however, NASA's ...

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.

NASA artist’s conception of a brown dwarf (main) and stock image of the planets in the solar system (inset). An object between 2 and 50 times the mass of Jupiter may have flown through our ...

Scientists believe that two asteroids might be fragments of long-lost "planetary embryos" from the early solar system.

Jupiter’s famous clouds aren’t ammonia ice but a murky mix of chemicals, sitting lower in the atmosphere than expected. For years, astronomers believed that Jupiter’s upper clouds — responsible for it ...

NASA's Juno spacecraft has discovered a giant volcanic hot spot on the surface of Jupiter's hellish moon Io. The eruptions in ...

The acid yellow moon Io that orbits Jupiter may be less than 30% the size of Earth, but is considered the most volcanic body in our solar system. As demonstrated by explosive news from NASA on ...

Stock illustration of all the solar system's planets. Mars, Venus, Jupiter, Saturn, Uranus and Neptune will be visible all at once this month. Stock illustration of all the solar system's planets.

An interstellar visitor may have warped the solar system billions of years ago, a new study has claimed. Scientists suggested the enormous object disrupted the orbits of Jupiter, Saturn ...