An ocean below the surface of Jupiter's large moon Ganymede has more water than all earthly oceans, according to evidence from the Hubble Space Telescope.
At least! Six other objects could be either dwarf galaxies or globular clusters. These humble Milky Way satellites are a key to the dark matter puzzle.
There are currently 40 different Saros series in progress, each with its own assigned number. The total solar eclipse of March 20, 2015 belongs to Saros 120.
A stack of four identical spacecraft will study Earth's magnetosphere - the comet-shaped magnetic shield that protects us from "space weather." Watch the launch.
The sun has been relatively quiet, and this is the first X-flare of 2015. It caused a brief radio blackout at some frequencies. Possible aurora alert ahead.
A quiet night for auroras at Churchill, Manitoba, Canada - located at at 58° North, under the auroral oval - is a spectacular auroral display for most of us.
Were it possible to see the skies from this world, the four parent stars would look like one small sun and two very bright stars visible in the daylight.
About 4 billion years ago, a primitive ocean on Mars held more water than Earth's Arctic Ocean, say researchers, but Mars has lost 87 percent of it to space.