Europa’s freckles

Reddish spots and shallow pits that pepper the surface of Jupiter’s moon Europa may mark regions where warmer and less dense ice, possibly from an ocean buried deep beneath the moon’s frigid surface, percolates to the surface.

The spots and pits, each about 10 kilometers in diameter, run across the northern hemisphere of Europa, according to a new analysis of images taken in 1996 and 1998 by the Galileo spacecraft.