The Centaur of the Galaxy

Aug 3, 2015

  

The Steamin' Teapot of Sagittarius...
Credit M. Procell

  This is “Looking UP! in southern Colorado,” from the Colorado Springs Astronomical Society. I’m Hal Bidlack, and there are lots of reasons to look up!

Now that we’re well into summer the constellation Sagittarius soars in the southern Colorado sky. If you look at a star chart, Sagittarius is shown to be a centaur with a bow and arrow. But frankly, that shape is pretty hard to spot. But there is a part of the Sagittarius constellation, however, that does leap out - the famous teapot. 

This collection of eight stars make up a shape that looks very much like, well, a teapot in the sky. A group of stars that make up a pattern within a larger constellation is called an asterism. The most famous example of an asterism is the Big Dipper, which is part of a larger constellation Ursa Major or the Great Bear.

The teapot is special for a couple of reasons. First, if you are able to get away from city lights, say at one of our star parties at the Florissant Fossil Beds National Monument, you can see that the vast band of the Milky Way across the sky appears to be the steam coming out of the spout of the teapot. The combined light of millions and millions of stars, too far away to be seen individually, create this dazzling band of light across the sky.

The other remarkable thing about the teapot is that the spout appears to be pouring out into the night sky at the exact point that marks the direction to the center of our Milky Way galaxy, about 30,000 light years away. Our galaxy is a vast spinning pinwheel of at least 100 billion stars. The entire galaxy is 100,000 to 150,000 light years across. From our location part way out in one of the spiral arms, the center of the galaxy, and the massive black hole located there, are just above the spout of the teapot. That black hole is at least 4 ½ million times more massive than our sun, and strange things happen in that region. Black holes are unbelievably dense. Their gravity is so strong that not even light can escape their surface. Hence, they’re a “Black Hole”. Be glad it’s so far away.

So pour yourself a cup of tea, and head outside to see the biggest teapot in the night sky.

If you’d like to take a closer look at the Teapot or any of the other wonderful and amazing things in the sky, please visit KRCC.org or CSASTRO.org for a link to information on our monthly meetings and our free public star parties! 

This is Hal Bidlack for the Colorado Springs Astronomical Society, telling you to keep looking up, Southern Colorado!