Volcanic caves are not just an Earth thing. Scientists have spotted signs of lava tubes on the Moon and Mars. Now, ...

Mercury has long been cast as the solar system’s burnt-out rock, a relic too small and too close to the Sun to hold many ...

The two halves of the African continent are moving apart at a rate of a few millimeters each year, geologists have calculated.

Gas giants are massive worlds made mostly of hydrogen and helium. They lack solid surfaces, and in our solar system, Jupiter ...