Saturn now leads the solar system with 274 known moons. Scientists say many moons formed from past collisions.

Venus will pass between the Earth and sun during what’s called an inferior conjunction. But don’t plan on seeing the linkup.

The relative quantities of volatile gases like methane and ethane can reveal key details about distant Kuiper Belt objects.

A NASA spacecraft will make its second close brush with the sun. The Parker Solar Probe made its record-breaking first pass ...