Three massive volcanic eruptions that occurred on Jupiter's moon, Io, in August 2013 have made astronomers think twice about how often these outbursts occur. Since the eruptions happened within just a two-week period, scientists are considering that they might be far more common than once thought.
Io is the innermost of Jupiter's four "Galilean" moons. About 2,300 miles across, it's the only known place in the solar system, aside from Earth, with volcanoes erupting extremely hot lava. Because of its low gravity, the eruptions on Io spew lava into the air that can rise high into space.