M31
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M31 |
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Deep Sky Object Chart | Epsilon Pegasi (Enif) | Upsilon Andromedae | 32 Pegasi | 51 Pegasi | M15 | M31 | M33 | NGC 752 | NGC 891 | NGC 7331 | NGC 7662 | NGC 7814 | M74 M31 is the technical number for what is more often called the Great Andromeda Galaxy, and "great" is right: spanning an area wider than eight full moons, this monster is so bright you can see it with the unaided eye from dark sites. Other galaxies require a telescope, but this one has been known since antiquity; the first recorded mention dates to 905 BC. In the early days of the telescope, astronomers wondered if M31 was a swirl of gas forming a new solar system, but the truth is more spectacular - it is a vast swarm of stars, hundreds of billions of them. The dimensions are greater than our own Milky Way, in fact: fully 180,000 light years to our more modest 100,000. Still, the general form of M31 is similar to our galaxy's, and in looking across 2.2 million light years we are seeing how we would look, a lonely star metropolis among the blackness. The fact that M31 is the nearest large galaxy to ours gives some idea of the vastness of the universe - 2 million light years is nothing! In small telescopes, the two smaller companion galaxies (suburbs, so to speak) are easily seen, and large telescopes and photographs reveal intricate details in this important celestial object.
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