21 Facts About Andromeda Galaxy


Andromeda Galaxy, known as Messier 31, M31, or NGC 224 and originally the Andromeda Nebula, is a barred spiral galaxy with diameter of about 46.

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Andromeda Galaxy referred to it in his Book of Fixed Stars as a "nebulous smear" or "small cloud".

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Andromeda Galaxy's spectrum is very similar to the spectra of individual stars, and from this, it was deduced that Andromeda Galaxy has a stellar nature.

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Andromeda Galaxy was considered to be a nearby object, and it was not realized that the "nova" was much brighter than ordinary novae.

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Andromeda Galaxy became a proponent of the so-called "island universes" hypothesis, which held that spiral nebulae were actually independent galaxies.

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Andromeda Galaxy's measurement demonstrated conclusively that this feature was not a cluster of stars and gas within our own galaxy, but an entirely separate galaxy located a significant distance from the Milky Way.

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In 1950, radio emission from the Andromeda Galaxy was detected by Hanbury Brown and Cyril Hazard at Jodrell Bank Observatory.

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Andromeda Galaxy was formed roughly 10 billion years ago from the collision and subsequent merger of smaller protogalaxies.

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In 2006, the Andromeda Galaxy's spheroid was determined to have a higher stellar density than that of the Milky Way, and its galactic stellar disk was estimated at about twice the diameter of that of the Milky Way.

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Andromeda Galaxy is surrounded by a massive halo of hot gas that is estimated to contain half the mass of the stars in the galaxy.

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However, infrared data from the 2MASS survey and from the Spitzer Space Telescope showed that Andromeda is actually a barred spiral galaxy, like the Milky Way, with Andromeda's bar major axis oriented 55 degrees anti-clockwise from the disc major axis.

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Spiral arms of the Andromeda Galaxy are outlined by a series of HII regions, first studied in great detail by Walter Baade and described by him as resembling "beads on a string".

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Andromeda Galaxy's studies show two spiral arms that appear to be tightly wound, although they are more widely spaced than in our galaxy.

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Since the Andromeda Galaxy is seen close to edge-on, it is difficult to study its spiral structure.

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Studies of the extended halo of the Andromeda Galaxy show that it is roughly comparable to that of the Milky Way, with stars in the halo being generally "metal-poor", and increasingly so with greater distance.

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Andromeda Galaxy is known to harbor a dense and compact star cluster at its very center.

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Multiple X-ray sources have since been detected in the Andromeda Galaxy, using observations from the European Space Agency's XMM-Newton orbiting observatory.

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Triangulum Galaxy is a non-dwarf galaxy that lies 750,000 light years from Andromeda.

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In 2006, it was discovered that nine of the satellite galaxies lie in a plane that intersects the core of the Andromeda Galaxy; they are not randomly arranged as would be expected from independent interactions.

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Andromeda Galaxy is approaching the Milky Way at about 110 kilometres per second.

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Under most viewing conditions, the Andromeda Galaxy is one of the most distant objects that can be seen with the naked eye.

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