Saturday, February 7, 2015

The Discovery of the Ever-Expanding Universe

For a long time people thought that the universe was unchanging and that the universe was just infinite and static.Even Albert Einstein himself believed in this idea so when he tried to solve this problem of what the universe was like, he assumed that the universe was static and his original solution had a constant called the cosmological constant. He later said that this was probably the biggest blunder in all of his work. Edwin Hubble started to observe the distance to galaxies. Hubble showed that the velocity of a galaxy increased as its distance to earth got farther and farther. This meant that the universe was in fact expanding and the farther away something is, the faster it appears to move away because of the universe expanding. Hubble actually used Vesto Slipher’s (the discoverer of galactic redshifts) observations of the redshift of galaxies, combined with his own observations to propose Hubble’s law and his idea of the expansion of the universe.

George Lemaitre also proposed the idea that the universe is ever-expanding and came to the realization that at some point it must have existed as a single point; and that was the birth of what is now called the Big Bang theory. Lemaitre argued that if you go far enough back in time the universe must have started as a single particle (the primeval atom). Lemaitre was also responsible for being the first to derive Hubble’s law as well as give an estimation of the Hubble Constant. He thought that the universe would never stop expanding. There are three possible different types of expanding universes. One would be that the universe is open meaning that it would just expand forever. The second type would be if the universe were flat. That would mean that the universe expands forever but at a certain point the expansion rate would slow down to zero after an infinite amount of time. However, if the universe were closed then it would stop expanding at a certain point and collapse on itself due to gravity.

The idea that the universe is infinite and in fact ever-expanding is a very interesting one. Since the universe is infinite and there are so many galaxies out there that we have never even come close to exploring there are an infinite number of possibilities of what is out there. There may be another parallel universe where there are humans living there like us, wondering if anything else is out there. That is why it is so important to continue exploring space and trying to find possible ways to reach other galaxies. If we were to find a way to travel fast enough that we could get to another galaxy in a lifetime we could very likely find other life out there. If we never actually take these steps to explore we could be missing out on a lot of different things. There is an infinite amount of possibilities of what could be out there and the faster that we can cover as much ground as possible the more likely we can discover extraterrestrial life.
- Eric Chow