Close flybys of Io, one of Jupiter's moons and the most volcanically active world in our solar system, have revealed a lava lake and a towering feature called "Steeple Mountain" on the moon's ...
Revealing Io's mysteries Io, first discovered by Galileo Galilei in 1610, is just slightly larger than our moon, but it's unlike anywhere else in the solar system. The rocky moon's surface is ...