Not all of the solar system’s building blocks formed simultaneously. Some of the first solid bodies, or planetesimals, formed in the first million years after the Sun was born. Others, including the ...

Spectacular clouds swirl across the surface of Jupiter. These clouds contain water, just like Earth's, but are much denser on ...

While Io, the most volcanically active moon in the solar system, appears completely dry and devoid of water ice, its neighbor ...