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

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

Mars is home to perhaps the greatest mystery of the solar system: the so-called Martian dichotomy, which has baffled ...

Simpson and Chen ran mathematical models looking at how differently sized Earth-like worlds would have affected the rest of ...

Baker said that there are other astronomical events that may be more interesting than the parade of planets. Baker said Mars ...

Worlds will align for a "planetary parade" in January, with four bright and easily visible to the naked eye. But an even ...

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

The contrast between two clusters of marsquakes has led two scientists to suspect the internal structure of the Red Planet is ...

All seven of the other planets in our solar system are about to become visible at once in a great planetary alignment – ...

Although it's being mistakenly promoted as a "rare planetary alignment," one of the best "planet parades" in half a century ...

Pluto-Charon Formation Scenario Mimics Earth-Moon System Jan ... Dust storms on Mars could one day pose dangers to human astronauts, damaging equipment and burying solar panels.

Tonight and throughout January, stargazers can see a planetary alignment in the night sky or what some are calling a ...