Io’s True Colors


io_truecolorJupiter’s moon Io is one of the weirdest in the Solar System. It’s bright yellow, and this picture is an attempt to show how Io would appear to the average human eye. Io’s colors derive from sulfur and molten silicate rock. The moon’s is constantly being refreshed by a system of active volcanoes. Tides caused by Jupiter’s gravity stretch Io, and the resulting friction greatly heats Io’s interior, causing molten rock to explode through the surface. Io’s volcanoes are so active that they are effectively turning the whole moon inside out. Some of Io’s volcanic lava is so hot it glows in the dark.

Image Credit: NASA

Under Construction


ioplus_galileo_960Jupiter’s moon Io’s surface is constantly under construction. Io holds the distinction of being the Solar System’s most volcanically active body; its weird surface is continuously remade by lava flows. This high resolution composite picture was put together from images taken by the Galileo spacecraft back in 1996. It shows the side of Io that always faces away from Jupiter. The picture has been processed to bring out the moon’s surface brightness and color variations and shows details small as 2.5 km across. There aren’t many impact craters on Io which suggests that the entire surface gets covered with new volcanic deposits more rapidly than craters are created. The likely energy source for the vulcanism is the changing gravitational tides caused by Jupiter and the other three Galilean moons (Callisto, Ganymede, and Europa) as Io orbits the massive planet. The tides would heat the interior of the moon and generate its sulfurous volcanic activity.

Image Credit: NASA

A Volcano on a Moon of Jupiter


io_lokiLoki Patera is the largest volcanic depression on Jupiter’s moon Io, 202 km in diameter. It contains an active lava lake, with an episodically overturning crust. Voyager 1 took this composite picture of Io showing an active plume from Loki on the moon’s limb. The images that make up this mosaic were taken from an average distance of approximately 490,000 km.

Image Credit: NASA

Io, Io, It’s Off To Pluto We Go


A plume rises from a volcano over 300 km above Jupiter’s moon Io in this image from the New Horizons spacecraft. The volcano Tvashtar is marked by the bright glow (about 1 o’clock) at the moon’s edge, beyond the day/night shadow line. The shadow of Io cuts across the plume itself. The image was recorded when the spacecraft was 2.3 million kilometers from Io. The New Horizons spacecraft is to encounter Pluto in 2015.

Image Credit: NASA