Our Closest Galaxy

Pop quiz!  What’s the closest galaxy to our Milky Way?

Nope! It’s not Andromeda.  And, it is not the Large or the Small Magellanic Clouds. (Which all those who live in the Southern Hemisphere get to see!)

The closest galaxy to ours is the irregular dwarf galaxy Canis Major, which is about 42,000 light-years from the center of the Milky Way.  The galaxy was only discovered in 2003, as it is obscured by dust and gas that lays within the Milky Way.  Andromeda (M31) is about 2.5 million light years away from us, which makes it the 35th most distant galaxy from the Milky Way.  Andromeda is the closest spiral galaxy to the Milky Way.

The Andromeda galaxy has the distinction of the being the largest galaxy in our gravitationally bound local group of about 40 galaxies.  It’s about twice as big as Milky Way, and that places our galaxy as the second largest in the group, followed by Triangulum (M33), a beautiful spiral galaxy that is possibly a satellite galaxy of Andromeda.

Andromeda Galaxy - Image by Tony Hallas http://astrophoto.com/contact.htm Triangulum Galaxy - Image by Manfred Konrad http://www.astrofotografie-laupheim.de/

Till next time,

RC Davison

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