Today we have the third guest post by my resident astronomer, Evan, the other half of Bamboo Shoots Photography. Check out our other Palomar Observatory astrophotography post and our Los Angeles astrophotography post here!
Two centuries ago, searching for comets was all the rage. The European well-to-do would try to see who could find the most comets. As a service to other astronomers, Charles Messier kept a list of fuzzy objects in the sky that did not move from night to night and therefore were not comets.
We took this photo of the eastern sky from Palomar Observatory. You’re looking right at the center of our own Galaxy, the Milky Way. It sometimes helps to orient your view of the night sky if you know where the constellations are, so we’ve drawn lines showing pieces of a few constellations: Serpens Cauda (the snake’s tail), Scutum (the shield), Sagittarius (the archer), and the tail of Scorpius (the scorpion).
The Galactic center is a busy place, so there’s a lot of cool stuff in the sky when you look in this direction. For example, this image contains five Messier objects.
Messier 6, 7, and 23 are open clusters, the birth places of stars. Almost all stars in our Galaxy formed in loose collections of stars like these. Our own Sun formed in an open cluster, which dispersed billions of years ago. Some astronomers make it their life goals to find “solar twins,” stars that were born in the same cluster as the Sun.
Messier 8 is also an open cluster, but it contains a nebula. Nebulae are the Galaxy’s recycling bins. When some stars die, they blow up into gas clouds. Pieces of those same clouds can collapse to form brand new stars. This cycle has been recurring for the last 13 billion years. Nebulae are also some of the most beautiful objects in the night sky. If you have binoculars or even a telescope, try to find M8 in the summer evening sky. You will see the Lagoon Nebula.
My own favorite object is Messier 22. It is a very tight group of stars called a globular cluster. Unlike open clusters, globular clusters are not stellar nurseries. In fact, the stars in M22 are nearly as old as the Universe. Globular clusters can be somewhat boring because all of the stars are made of almost the exact same stuff. For example, one star has just as much iron as the next. However, M22 was very recently found to be an exception. It’s a very rare globular cluster where all of the stars do not have exactly the same composition. One of my scientific goals is to figure out why some globular clusters, like M22, show some personality!