... Europa: The Latest From Galileo . ... Black Hole Signature From Advective Disks . ... If alone, a black hole would indeed appear quite black, but many black hole candidates are part of binary star systems. ... These spots appear dark in photographs like the one above, but in fact sunspots are quite bright - they are just dark compared to the rest of the Sun. Sunspots are about the size of the Earth and frequently occur in groups, as shown above. Mercury in Stereo: Craters Within Craters . ...