When the Jovian moon called Io goes into the shadow of Jupiter, it glows in the dark.
Io's surface is invisible in the darkness, but the image reveals glowing hot lava, auroral displays in Io's tenuous atmosphere and volcanic plumes across the moon. The three bright points of light on the right side of Io are incandescent lava at active volcanoes - Pele and Reiden (south of the equator), and a previously unknown volcano near 22 degrees north, 233 degrees west near the edge of the disk at the 2 o'clock position.
This spectacular image courtesy of NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute. Read more about it here.