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” ...

One summer night in 1877, American astronomer Asaph Hall was looking through his telescope in Washington, D.C. Mars was at its closest point to Earth in its orbit, and Hall had one question on his ...

Forbes contributors publish independent expert analyses and insights. An award-winning reporter writing about stargazing and the night sky. Martian moon Deimos appears dark, framed by the brighter ...

Six planets in the solar system have at least one moon. Both Earth and Mars are toward the lower end of the lunar count, as our home planet only has one moon, and Mars has two. But not all moons share ...

As an astronomer studying the universe beyond Earth, I’m fond of “outside the box” views almost by default. But one of my favorites is whenever a spacecraft takes a snapshot of our home world and the ...