The proper motions of the stars in the immediate neighbourhood of the Sun are usually very large, as compared with those of most other stars. Those of stars within 17 light-years of the Sun, for instance, range from 0.49 to 10.31 arc seconds per year. The latter value is that of Barnard’s star, which is the star with the largest known proper motion. The tangential velocity of Barnard’s star is 90 km/sec, and, from its radial velocity (−108 km/sec) and distance (6 light-years), astronomers have found that its space velocity (total velocity with respect to the Sun) is 140 km/sec. The distance to this star is rapidly decreasing; it will reach a minimum value of 3.5 light-years in about the year 11,800.
Milky-Way-Galaxy-as-seen-from-EarthMilky Way Galaxy as seen from Earth[Credits : © Dirk Hoppe]
Bright-nebulosity-in-the-Pleiades-distance-490-light-yearsBright nebulosity in the Pleiades (M45, NGC 1432), distance 490 light-years.[Credits : Hale Observatories ©1961]
Centre-of-the-Orion-Nebula-Astronomers-have-identified-some-700Centre of the Orion Nebula (M42).[Credits : Photo AURA/STScI/NASA/JPL (NASA photo # STScI-PRC95-45a)]
Composite-picture-of-the-Cats-Eye-Nebula-combining-three-imagesComposite picture of the Cat’s Eye Nebula (NGC 6543), combining three images taken by the Hubble …[Credits : Photo AURA/STScI/NASA/JPL (NASA photo # STScI-PRC95-01a)]
The-Crab-Nebula-which-was-formed-by-a-supernova-explosionThe Crab Nebula, which was formed by a supernova explosion recorded in 1054. This image was made by …[Credits : NASA]
The-Eagle-NebulaThe Eagle Nebula. Stars are forming in this column of cold dust and gas, which is 9.5 light-years …[Credits : NASA, ESA, and The Hubble Heritage Team (STScI/AURA)]
Horsehead-NebulaHorsehead Nebula[Credits : © Anglo-Australian Observatory]
Globular-cluster-NGC-1850-in-the-Large-Magellanic-CloudGlobular cluster NGC 1850 in the Large Magellanic Cloud.[Credits : Photo AURA/STScI/NASA/JPL (NASA photo # STScI-PRC94-40)]
Our solar system is just a miniscule part of a much larger system called the Milky Way Galaxy.[Credits : Acquired from Vast Video]
The universe is made up of many stars, solar systems, and galaxies.[Credits : Acquired from Vast Video]
Using their telescope, the brother and sister team of William and Caroline Herschel discovered the …[Credits : Acquired from Vast Video]
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