A recent discovery suggests Mars may have once had a much larger moon, which could have caused tides in a lake that once filled Gale Crater. This intriguing possibility comes from a study of sediment ...

Mars, a world now circled by two lumpy rocks, may once have hosted a colossal companion that dominated its sky. New work on the planet’s tides, topography and wobbly interior points to a “lost” ...

Although both moons orbit Mars much closer than our own Moon orbits Earth, they also are very small: Phobos measures only 12 miles (19 kilometers) across and Deimos is half that. Their apparent sizes ...

Searching for clues on Phobos and Deimos. Damond Benningfield The Mars Moons eXploration spacecraft will fire its thrusters to maneuver into orbit around Mars (depicted in this digital art). JAXA Mars ...

Mars’ moons are easily visible at night from the surface of the Red Planet. Phobos – the nearer, larger, and brighter of the two – would be obviously non-round. A sharp-eyed observer would be able to ...