An amateur astronomer may have found the first crater ever spotted on Jupiter’s moon Io. Io is so volcanically active that eruptions tend to wipe away any impact craters, so we have never seen one until now.
Jesper Sandberg, an amateur astronomer in Sweden, spotted this apparent crater while combing through archival images from the Galileo spacecraft, which orbited Jupiter from 1995 to 2003. It is relatively small, just about 100 metres across, and…