Our galactic neighbour, rising over the Italian AlpsThe Andromeda galaxy is speeding towards ours at
Our galactic neighbour, rising over the Italian AlpsThe Andromeda galaxy is speeding towards ours at a large rate of knots, and in some 4 billion years the two galaxies will collide in a slow motion minuet that will ignite a huge burst of star formation in both island universes. At the moment it is still some 2.5 million light years away, but it is so bright it is visible to the naked eye as a light smudge if you know where to look and have a reasonably dark sky (in fact its visibility or lack thereof is a good test of what astronomers call ‘seeing’).Also known as M31 (from a catalogue compiled by Charles Messier in the late 19th/early 19th centuries that was intended to mark these objects so that they would not be confused with comets), like our galaxy it is the largest in the local group and has some 16 satellite star clumps orbiting it. Our first recorded sighting dates from 965, when the Persian astronomer Abd al-Rahman al Sufi mentioned it in his Book of Fixed Stars (while mystics, the Sufi orders produced a lot of tomes of practical knowledge, from star charts and glassmaking to animal husbandry, mostly anonymously like we do here at TES). Early star charts label it as the little cloud. Galaxies were not proved to lie beyond our immediate neighbourhood until the 1920’s, and the debate was settled by Erwin Hubble in 1925 when he identified a type of variable star with fixed properties called Cepheids that allow distances to be measured.LozImage credit: Matteo Dunchihttp://space-facts.com/andromeda/https://www.sciencefocus.com/space/how-can-i-see-the-andromeda-galaxy/ -- source link
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