Amateur astronomers may have discovered the first crater ever discovered on Jupiter’s moon Io. Io has never seen an impact crater before because it is very volcanically active and eruptions tend to erase impact craters.

Swedish amateur astronomer Jesper Sandberg discovered the apparent crater while examining archival images from the Galileo spacecraft, which orbited Jupiter from 1995 to 2003. It is relatively small, only about 100 meters in diameter, and is located on a large, flat area.