Scott Sheppard of the University of Hawaii, has discovered a 40th moon orbiting Jupiter. He was using a 2.2-meter telescope, on top of the Hawaiian mountain Mauna Kea.
In a press statement, Sheppard said: "Since Jupiter is the largest planet in our solar system it has influenced our neighborhood second only to the sun."
The new moon has been called, S/2002 J1, and takes 748 days to orbit Jupiter. It is thought to be about 2.2 miles (3.5 km) in diameter.