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Gary Zientara/Mount Sangre Observatory

Triangulum galaxy (M33) imaged during mid-October from Mount Sangre Observatory. Although M33 is the third most massive in our local group of 40 galaxies, it's a relative pipsqueak compared to the Milky Way and Andromeda galaxies.

Messier 33 (M33) is a "nearby" galaxy 3 million light years away located in the Triangulum constellation.

It is an SC type spiral galaxy that contains many star nurseries as well as bright blue open star clusters. The most prominent star forming region is NGC 604. It is the large white blob with loopy reddish edges found along the outer portion of one of the sweeping spiral arms on the left side of the galaxy. You can see it better by zooming in on that area of the image. NGC 604 is 40 times larger than the Great Orion Nebula in our Milky Way galaxy.

As you study this image, understand that the individual stars you see are foreground stars located in the Milky Way. The mottled brown structures found in and between the spiral arms of M33 are regions of dust that are dense enough to block the light of stars shining behind them. The misty blue, yellow and red areas are produced by the surface temperatures of billions of stars. The blue ones are the hottest and youngest with older cooler yellow then red stars found progressively closer to the center of the galaxy.

To get a better perspective of how a spiral galaxy looks from the inside, compare one of M33's spiral arms to the foggy band of stars spanning from northeast to southwest that we see best in our summer and fall night skies. You would see something similar if our sun was embedded in the plane of rotation of the M33 galaxy.

The most unusual feature of M33 is the lack of a central bulge as is found in our Milky Way. This is most likely because no supermassive black hole exists at M33's center. Rather it's a comparatively small black hole at 3,000 times as massive as our sun.

Compare this to the one at the center of our galaxy that weighs in at over 4 million solar masses! Although M33 is the third most massive in our local group of 40 galaxies, it's a relative pipsqueak compared to the two "big kids" in the group (Milky Way and Andromeda galaxies).

You can see how distorted (elongated and pulled like taffy) M33 is. Poor M33 is slowly being ripped apart and will eventually be absorbed into the Andromeda galaxy's enormous gravity well. Andromeda has already stretched one of M33's spiral arms toward it. Several billion years from now the Milky Way, Andromeda and M33 will merge to form a supergalaxy which will most likely display a drab featureless elliptical shape.

Gary Zientara owns and operates Mount Sangre Observatory in Angel Fire.

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