This was the final objective within my Astronomy 101 class. In one full day, we learned about how Astronomers decipher the age of the universe, as well as how the universe expands. To kick things off, Professor Morrison brought out the overhead projector to present a demo. The purpose of this demo was too understand how Hubble’s law tells the universes age.
We looked at a bunch of drawn in galaxies, and then as a class decided which galaxy was going to play the role of the Milky Way. After a great deal of consolation, we finally found the perfect pretend galaxy to represent our home. Our Professor, then took another sheet with the same drawings but enlarged. This next sheet was laid on top of the previous sheet too represent something important. This demo proved that galaxies appear to be moving away from the Milky Way. To further our hypothesis, we chose another galaxy to represent the Milky Way, in which we received the same results. In conclusion, it does not matter what galaxy you are in; from your perspective the other galaxies will appear to shift away from your current position.
The above information represents the idea that at some point in time, galaxies have been closer together. To put simply, space used to be compressed, but then a phenomenon known as the “Big Bang” forced everything to implode, which is why space is now rapidly expanding. This idea triggers many scientific question such as, if the universe is expanding what happened to the very first light? To answer this question, it is important to understand that the universe is 1,000 times larger now; as its wavelengths are also 1,000 larger as well. Therefore, the very first light was stretched, as it continues to be stretched. To prove this point, scientists greater a scale known as the black body. This scale measures the temperature of the universe, which plays an important role within the creation and expansion of it. Followed by the blackbody scale, scientist have then created the WMAP which is the best map of the universe. This map presents the temperatures of each part of space. This is important because by understanding the significant temperature changes, scientists now understanding that stars were formed due to the hotness, that then formed quasars, which then turned to galaxies, which created more stars, causing them to die, which caused the planets to form, and now we are here living on Earth.
The most important fact to get out of this current objective would be that the universe is rapidly expanding. The significant increase in expansion would be caused by something called Dark Energy. Neither scientist nor astronomers understand Dark Energy, as they know nothing about it; however, it makes up over 75% of the universe’s energy.
I found an article that expresses the uncertainty of Dark Energy. This article details the potential fate of our universe as scientists attempt to seek answers regarding this energy. This article pertains to the different ideas discussed within our lecture, because it elaborates on how greatly the universe is affected by this unknown energy. Overall, I found the article rather interesting, and would recommend it! Here is the link to it: https://aasnova.org/2019/04/05/supernovae-dark-energy-and-the-fate-of-our-universe/