New Horizons shows us the biggest volcanic eruption yet on Jupiter's hot moon Io.
New Horizons captured a remarkable image of the volcanic moon Io as it sped past Jupiter on its way out to Pluto. The image shows the most detail yet of a volcanic eruption on another world.
The plume, first seen by the Hubble Space Telescope in mid-February, emanates from the Tvashtar volcano between the 11 and 12 o'clock position in the photo of Io. When New Horizons took this photo, it was one and a half million miles from the Galilean satellite on February 28, 2007.
The volcanic plume shoots about 180 miles above the surface of Io. In comparison, Mount Pinatubo's eruption on Earth in 1991 reached a height of 21 miles. The intricate structure seen in the Tvashtar cloud suggests that the particles are changing from a gas to a solid up above the moon's surface, where they would then fall back down like a volcanic snow.
Io is such an active world that two other volcanoes can be seen erupting in this picture. Prometheus, the original focus of New Horizon's image, appears at 9 o'clock. Its uniform spray of volcanic material can be seen clearly in the larger image.
The third volcano in the image is Masubi. Masubi is near the bottom on the night side of the satellite; however, its ejecta has been flung high enough that it is captured in light reflected off Jupiter.
Gigantic mountains also stand in stark relief in this image. Some of them cast large shadows on the daylit side and one pokes up high enough on the night side for its top to be illuminated.
A gallery of other images taken at Jupiter by New Horizons can be found at the NASA website.
New Horizon has now gained its gravitational boost from Jupiter and is speeding off toward Pluto, which it is expected to reach sometime in the year 2015.
