An ultraviolet view of the Large Magellanic Cloud from Swift&#039;s Ultraviolet/Optical Telescope. Almost 1 million ultraviolet sources are visible in the image, which took 5.4 days of cumulative exposure to do. The wavelengths of UV shown in this picture are mostly blocked on Earth&#039;s surface. Credit: NASA/Swift/S. Immler (Goddard) and M. Siegel (Penn State)