... Credit Copyright: DIRBE , COBE , NASA Explanation: Although the Earth is round, our Galaxy appears truly flat. This was shown in dramatic fashion by the COsmic Background Explorer (COBE) satellite which produced this premier view of the central region of our own Milky Way Galaxy in infrared light in1990. ... The DIRBE module used equipment cooled by a tub of liquid helium to detect the infrared light which, composed of wavelengths longer than red light , is invisible to the human eye . ...