Curious about how many moons Mars has? Discover fun facts about Phobos and Deimos — Mars' two tiny moons — including their ...

A recent study found that Jupiter was once twice the size that it is now, making it big enough to swallow up 2,000 Earths.

Astronomers have calculated that the gas giant Jupiter used to be twice as big as it is now, based on the odd orbits of two ...

According to their work, Jupiter's radius was once two to two-and-a-half times its current radius—large enough to contain ...

Scientific American spoke with the astronomer who has contributed to the discovery of two thirds of Saturn’s known moons ...

The new calculations, described in a paper published Tuesday (May 20) in the journal Nature Astronomy, suggest that just 3.8 ...

The study by Konstantin Batygin of Caltech and Fred Adams of the University of Michigan pulls off a rare feat in planetary ...

A new study has revealed that Jupiter—our solar system’s largest planet—was once even more enormous than it is today. In fact ...

Today, it’s believed that Jupiter and Saturn, the largest planets, were the first to fully form, both within a few million ...

Jupiter wasn’t always the planet we know today—it was once twice as big, had a magnetic field 50 times stronger, and its ...

Though little is known about Deimos, another European spacecraft recently captured unprecedented views of the moon's far side ...

Meteor showers, eclipses and full moons will appear in our skies this summer. Mark your calendars with these dates, stargazers.