Quasars Reveal Early Structure of Milky Way-Like Galaxies

ALMA, or Atacama Large Millimeter/submillimeter Array, has allowed  astronomers to collect pictures of Milky Way-like galaxies as they are forming billions of light-years away. Jesse Emspak explains in the article, “Quasars Reveal Early Structure of Milky Way-Like Galaxies” that during this time, the universe was only about 2 billion years old, as these galaxies  are near 12 billion light-years away from us. Using Infrared light, scientists noticed large discs of hydrogen gas that stretched far past the star-forming regions. The galaxies also had rotating discs containing dust and gas and while stars formed at a surprising rate at 100 solar masses per year. Two galaxies, ALMA J081740.86+135138.2 and ALMA J120110.26+211756.2 were able to be spotted by using the light from two quasars in the background, which are enormous black holes that are surrounded by accretion discs. Normally seeing a galaxy while in front of a quasar is not easy but from using infrared light astronomers were able to see light from the galaxies’ ionized carbon, as well as hydrogen that shadowed from the light from the quasars. The ionized carbon allowed the researchers to see the structure of each galaxy, while also being able to see where stars were being formed from the emissions of infrared light from dust.  Research shows that the galaxies have already begun rotating which gives galaxies appear to have arms, or what are known as spiral galaxies.  Using quasars as a method of finding galaxies began back in 2003. After several years astronomers have found these ancient galaxies and also discovered that early galaxies have hydrogen clouds that extend much more than originally believed.

I find it unbelievable that these ancient galaxies are  12 billion light-years away yet astronomers are still able to see them and actually do research on them.  It surprises me how advanced technology is to observe some distant objects. Its very strange to think that these galaxies are several billion years old yet we are able to watch them form. An interesting fact I learned from this article is that the cosmos is about 13.8 billion years old. I find it crazy that scientists are able to predict the age of this. I enjoyed this article but I wish they went a little more into detail. The only similarity that was mentioned between these ancient galaxies and the Milky Way is that they are both spiral galaxies. I am curious if their are any other similarities. This article relates to our 16th conceptual objective: I can compare the Milky Way galaxy to other galaxies. Our Milky Way is just one of billions of galaxies in the universe, which means some may be like ours while others can be completely different. As we went over in class, their are three common galaxy structures: Elliptical, spiral and irregular galaxies. 20170507_191952

From our lecture-tutorial notes, galaxies 1,3,5 and 8 are elliptical galaxies. From “Galaxy Classification” I learned that elliptical galaxies consist mostly of old, red stars giving the galaxy a reddish-yellow coloring. These galaxies are usually very large and do not contain much gas or dust.  There are very few young stars in these types of galaxies. Spiral galaxies look like 2,4,6, and 7. Spiral galaxies have large discs of dust and gas with a large center bulge. In the dust and gas filled discs, many new stars are being formed while older red stars are in the center bulge where no new stars are being formed. The star formation causes white and blue hues which gives spiral galaxies their purple and blue coloring. Our galaxy the Milky Way is a spiral galaxy as well as the newly discovered ancient galaxies. Irregular galaxies don’t have a distinct shape. They are believed to be formed from two galaxies colliding. Irregular galaxies tend to be small but have active star formation.


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