Comet Garradd Sails Slowly Past Globular Star Cluster M92

Skywatcher Bill Snyder took this marvelous photo on February 3, 2012 from Heavens Mirror Observatory in the Sierra Nevada Mountains.

Comet Garradd sails slowly past globular star cluster Messier 92 (also known as M92 or NGC 6341) in this stunning image. The comet approached Messier 92 (M92) as it flew over the Hercules constellation. It passed within half a degree of Messier 92 (M92) on the day the image was taken. Messier 92 (M92) is one of the brightest globular clusters in the sky, and can sometimes be seen with the naked eye from the northern hemisphere. It was discovered by Johann Elert Bode in 1777 and independently rediscovered by Charles Messier on March 18, 1781. Messier 92 (M92) is located more than 27,000 light-years from Earth.A light-year is the distance light travels in one year, about 6 trillion miles, or 10 trillion kilometers. Comet Garradd is a slow-moving comet and has a magnitude of 6.5. Magnitude is used in astronomy to measure the brightness of an object. On this scale, smaller numbers represent brighter objects. The dimmest objects visible to the human eye are about magnitude 6.5, the same as Garradd. In the image, the comet Garradd appears to have two tails. The icy object begins to warm as it nears the sun and gas is created, forming the “halo” (called a coma) seen in the image. As the gas and rock particles in the coma move away, the gas is blown in one direction by solar wind while the rock particles ted to lag behind, creating the illusion of two tails.