|Why is the sky near Antares and Rho Ophiuchi so colorful? The
colors result from a mixture of objects and processes. Fine dust
illuminated from the front by starlight produces blue Gaseous
clouds whose atoms are excited by ultraviolet starlight produce
reddish emission nebulae. Backlit dust clouds block starlight
and so a red supergiant and one of the brighter stars in the
night sky, lights up the yellow-red clouds on the lower center.
lies at the center of the blue nebula near the top. The distant
globular cluster M4 is visible just to the right of and to the
lower left of the red cloud engulfing Sigma Scorpii. These star
clouds are even more colorful than humans can see, emitting
light across the electromagnetic spectrum. Credit & Copyright: