The expanding universe and what it means?
At this very moment, the universe is expanding at speed of 68 kilometres per second per megaparsec. But this expansion is linear, for if an object is two megaparsecs away, it would be moving away from us at 136 kilometres per second, and an object three megaparsecs away would be moving away at 204 kilometres a second, and etc. Expanding in a dimension that is not known to man. Quite possible into a dimension that houses multiple universes…… a multiverse. However, that is not what is going to be discussed today. As stated previously, the universe is rapidly expanding at a rate of 68 kilometres per second per megaparsec, but what is a megaparsec? A megaparsec is made up of one million parsecs which is an astronomical measurement which measures around three light years or about 9.461e+12 kilometres (the ‘e’ helps shorten the scientific notation from 9.461×10 to the 12th power, to 9.461e+12. The “+12” means move the decimal 12 places to the right). That means a megaparsec must be 3.086e+19 kilometres, or 3.262e+6 light years, in distance. That is impossible for any human to comprehend!! (phys.org) and (w.astro.berkley.edu).
But, when was this expansion discovered? Surly it had to be discovered in Newton’s time, right? Actually, no. In 1929, American astronomer Edwin Hubble (1889-1953) made this great discovery on Mt. Wilson Observatory in California. He is known to be one of the most influential scientists in modern science!! “But why is this important?” some may ask. Well, since scientists now know that the universe is expanding, they can safely say that it once had a beginning, it had a Big Bang. But, how did he find this out? I mean, you can’t see the actual expansion correct? Well, the expansion was observed indirectly by using the Doppler Effect. The Doppler Effect is the phenomena of sound or light waves being compressed or stretched out. For example, when a NASCAR race car passes by an observer, the sound it produces becomes high pitched, but when it travels away from the observer, the sound becomes lower in pitch. This is the Doppler Effect. Now, Dr. Hubble used this effect but in the sense of light. When he first discovered other galaxies, or known as “island universes”, he discovered that they were red-shifting or turning the colour red. The light turned red because as the light traveled through space, the expansion stretches it out. And since red is the longest wavelength of visible light, that is what we see. Who knew that one little property could prove such a big discovery? (biography.com).
In the past, there were great scientists that of Einstein, Newton, Copernicus, etc. Surly someone had to have theorized that the universe was expanding, right? Yes, and one great example was Einstein’s “biggest blunder”. In 1917 when Albert Einstein (1879-1955) was applying his newly published Theory of General Relativity to the structure of spacetime, he found out that his equations and methods did not add up when he applied it to a static universe. Because of this, he threw in this constant that would hold the universe from collapsing. He called this his “biggest blunder”. What was actually his biggest blunder was him saying that this was his biggest blunder. I say this because what his constant actually represented was dark energy. He said that there was a force acting upon the universe, and he was right. Dark energy, despite knowing very little about it, is known to accelerate the rate of the universe’s expansion. Even Einstein’s blunders were correct, that should give you a perspective on his intelligence. Lesser known, Russian-Soviet cosmologist and mathematician Aleksandr Friedmann (1888-1925) had made a theoretical framework of the universe expanding. With his inspiration from Einstein’s equations, he created the Friedmann Models. Essentially, he proposed that the universe started from a single point and expanded, the Big Bang, then will end in a Big Crunch. His model proposed not just a closed universe, a universe that will die and be born infinitely, but an opened universe, expanding infinitely, and a flat universe, a universe that expands infinitely but gradually getting closer to zero (atnf.csiro.au, britannica.com and phys.org). Because Friedmann found multiple solutions to Einstein’s equations, his model predicts three ends to the universe.
If something has a start, Mr. Friedmann, then it must has an end. It can’t just go on for infinity, right? So that means the universe is going to end, but how? Sadly, scientists do not know how or when, but they can theorize how. There are many ways the universe can end:
1: The Heat Death – Entropy is the process of things in an organized state becoming disorganized. Basically, as time goes on, disorder becomes greater as stated by the Second Law of Thermodynamics. At one point, this disorder will become so great that it will reach a thermodynamic equilibrium. At this equilibrium, everything and anything that consumes energy will cease to exist (britannica.com and chem.libratext.org).:
2 : The Big Crunch : gravitational pull from all of the objects in the universe become so intense, that the universe will begin to decreasing in acceleration. The universe will then reach a point of zero expansion, and then it will start to shrink. It is hypothesized that it will shrink back into a singularity and cause another Big Bang. This, in turn, will become an infinite cycle of Big Bangs and Big Crunches (windows2universe.org)
3: The Big Slurp: The process of quantum fluctuation, the spawning of an antiparticle and a particle pairs in the vacuum of space, creates a vacuum of a low energy state which will expand at the speed of light, ultimately, engulfing the whole entire universe. This is predicted to happen in billions of years so, no need to make that bunker of yours (imperium.news).
4: The Big Rip: Proposed back in 2003, it states that as the universe ages, dark energy increases in strength ultimately ripping the fabric of spacetime and atoms into shreds (imperium.news)
5: Or maybe, it does just go on for infinity. Maybe it is possible for something to have a start, but no end. This may trouble some, but it is a possibility that is worth taking note.
The discovery of an expanding universe is one of the most important discoveries EVER. This gave rise to many theories and models on the fate of the universe and the beginning of everything, one of the most asked philosophical and scientific questions along with “where did life come from?” and “what is our purpose?”. We humans may not stay in this universe forever, so we mustn’t soil it, we must embrace it.
: My name is Jason Pusic and I am a 15 year old science enthusiast. My interests primarily lay in physics, astronomy and astrophysics, but I am a fan of all sciences such as neuroscience, chemistry, evolutionary biology, etc. I hope everyone is loving what not only I post, but what all authors post on this magnificent website!