A defective pixel on an LCD screen. Bad pixels are often transistors that are permanently dead and appear as black dots or permanently energized and show up as white or colored dots ("hot pixels").

This is an 80-million-pixel picture of the star cluster RCW 38, located 5500 light-years away in the constellation Vela. RCW 38 is a young cluster containing about 2000 stars, and is bursting with ...