|
|
 |
Io, QTVR file, 530Kb, 320x200.
| | Io
Io has given us the most surprises. From telescopic observations astronomers knew that Io emits gases В including sulfur, sodium, potassium and oxygen В to fill a donut-shaped region around its orbit. Voyager 1 discovered that these gases came from active volcanoes on Io. Eight erupting volcanoes were photographed during its short flyby. This is far more than erupt at any one time on Earth. Io's high internal temperature is caused by tidal forces. The side of Io closest to Jupiter has a several-kilometer-high tidal bulge. Europa and Ganymede pull Io back and forth as they orbit Jupiter, making Io and its tidal bulge flex and buckle. The flexing heats Io, melting its interior and driving its volcanic eruptions. Instead of impact craters, Io has a great many volcanic features, including lava flows of sulfur-dominated silicates. | |
|  |
|
