Exploratour - Life in the Solar System
Io is very small, so there is not much gravity. For this reason, the air which comes out of Io's volcanos always drifts away. When the volcano's stop erupting, Io has no more atmosphere.
With little atmosphere, there is nothing between the surface of Io and space itself. This means that the temperature above the surface is very cold. On the other hand, when lava comes out of the volcanos, the surface of Io is sometimes super-hot!
All together these things add up to a very unfriendly environment for life as we know it on earth.
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