The Andromeda Galaxy – M31 (Messier Object 31), NGC 224

The Andromeda Galaxy - M31 (Messier Object 31), NGC 224

(Photo taken by: ME!)

M31 (Messier Object 31), also known as NGC 224 and, most famously, the Andromeda Galaxy. Most people know is at the closest galaxy to ours, the Milky Way. However, this is only true in one aspect. There are over 15 dwarf galaxies that are satellites of our own, large galaxy. There are also satellite galaxies of Andromeda that are closer to us than it is itself.

However, Andromeda is the closest galaxy that is large enough to be considered a main sequence galaxy. There are several more dwarf galaxies in the universe than large, main sequence galaxies such as Andromeda and our own. In these terms, Andromeda is our most immediate neighbor, and itis getting closer to us each second. It has been determined that this fate is almost definite in about 4 billion years. Computer simulations show the merger will happen and create a single mega-galaxy.

Galaxy collisions are quite common, and despite what intuition may lead you to thing, it will not be violent. It is unlikely many stars, if any at all, will collide. The closest star to the sun is about 4 light years. If the Sun were a ping pong ball, Proxima Centauri (the nearest star) would be a pea over 1,000 km away. So while collisions may happen, a long somewhat peaceful merger is the most likely scenario.

Andromeda is a naked eye object and lies to the east of the Cassiopeia constellation in the Andromeda constellation (hence, the name of the Andromeda Galaxy) for northern hemisphere viewers (like myself, in Florida).

It has rose back into prominence for viewers in the northern hemisphere lately, and with my night time photographing skills better than the previous year, I have taken to taking long-exposure pictures of it. To the naked eye it appears like a hazy smudge or star. Binoculars bring the diagonal smudge out for any lucky viewers.

It is slightly larger than our galaxy, but not by much. It’s volume is packer more tightly however, as it contains roughly 1 trillion stars. The Milky Way is not packed near as tightly (though only relatively) as it has an approximately 300 billion stars (about a third of Andromeda). If we could see all of Andromeda so that it’s arms were equally as luminous as its galactic nucleus then it would extent a couple times larger than the space the full moon inhabits in our sky.. so it is quite large from our vantage point.

When you take into account that it is over 00,000 light years wide and is 2.5 million light years away, this is quite amazing. In our sky lies a huge behemoth of a galaxy, easily viewable to all the masses, heading straight for us.. and though it is large and easily seen, we are only seeing it as it was 2.5 million years ago. We are looking WAY back in time when viewing it. The light reaching our eyes was sent before humans graced our planet.

..and it’s all right here in this photo. It’s in the sky.. look at it.. because there may be some other guy like myself, taking our pictures and explaining our galaxy on their own blog.


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