Mars's moon Phobos is so strange that no one knows how it formed. But a forthcoming mission could solve this mystery - and a host of other puzzles connected to the solar system's deep past ...

Phobos and Deimos – these names from Greek mythology were given to the moons of our neighbouring planet Mars, discovered in 1877 by the US astronomer Asaph Hall. Besides Earth's Moon, they are the ...

Deimos is Mars' outer moon. It's a tiny, irregularly shaped moon and smaller than Mars' other moon, Phobos. Despite being unspectacular, Deimos remains a fascinating mystery. Deimos is one of only ...