200723 - Comet C/2020 F3 "Neowise"

C/2020 F3 (NEOWISE) or "Comet NEOWISE" is a long period comet with a near-parabolic orbit discovered on March 27, 2020, by astronomers during the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer (WISE) space telescope.  At that time, it was an 18th-magnitude object (very dim), and was located appx 190 M miles away from the Sun and appx 160 M miles away from Earth.

NEOWISE (the Comet) is known for being the brightest in the northern hemisphere since Comet Hale–Bopp visited us in 1997.  Neowise was widely photographed by professional and amateur astronomers and was even spotted by people living near city centers and areas with light pollution.  While it was too close to the Sun to be observed as it achieved perihelion (the point nearest to the Sun as it orbits around behind it), it emerged from perihelion in early July 2020 at around magnitude 0.5 to 1.0, making it bright enough to be visible to the naked (unaided) eye. Under dark skies, it remained visible to the naked eye throughout July 2020.  By July 30, it had dimmed-down to about magnitude 5.0, when binoculars were required near urban areas to locate it.

In this image, a double tail is clearly visible, with the straight, blue-ish colored one being the "Ion" (EYE-on) tail composed of gaseous charged ion particles, and the other more curved white one being its "Dust" tail composed of dust and solid debris.  Both are created by the Sun's solar wind striking the comet and energizing its surface such that the rock and ice making up the comet itself  are released into space.  Each time a comet returns to visit, it is slowly melting away as it releases its compounds into space.  Both tails grew shorter as Neowise moved further away from the Sun.  Many scientists theorize that comets could be a major contributing source of where the water on Earth came from. 

Although the orientation of the tails appears in this fixed image to portray movement toward the bottom of the image, the movement of the comet was actually to the left.  Because NEOWISE's parabolic orbit around our sun is so large, scientists estimate it will not return again to be visible to the Earth for appx 5,600 years.