95% of the Universe is composed of this
By: Christian H. Oslapas
Tags: Dark Matter, NASA, Space, Dark Energy, Space Exploration

Written by Christian H. Oslapas on 8 July 2020.

The Universe is mostly composed of two mysterious substances called dark matter and dark energy.

An artist’s rendition of dark matter. (Photo from sakkmesterke/iStock photos1 )

Everything you have ever seen including all the galaxies, stars, planets, moons and blackholes account for only about 5% of the Universe. The majority of the Universe is composed of dark energy and dark matter. These substances are called dark because they do not interact with light. The Universe is expanding at an accelerated rate and dark energy is the driving force of this acceleration. Albert Einstein, Fritz Zwicky and even Aristotle all postulated on the medium of the Universe. About 95 percent of the universe is made out the combination of dark matter and dark energy. There are currently more questions than answers as to what dark matter and dark energy actually is. If you can correctly determine what dark matter and dark energy is, then you will surely win the Nobel Prize.

There are many different wonders to observe in the night sky including comets, meteorites and even distant stars exploding called supernovae. What is perhaps equally interesting is the substance that is between the stars and the planets: dark matter and dark energy. Although only recently detected, the idea that space has a mass and energy is not a new idea.

Around 300 B.C., Aristotle named the fifth element aether. Aristotle and his mentor Plato believed that the planets and space between the planets was made out of a material which they called aether. In the 1700’s, René Descartes again used the term aether to describe the medium of outer space. In 1887 the Michelson-Morley experiment tested to see if the Earth was indeed passing through a material. This experiment provided evidence that the Earth was not passing through a substance. From then on, many people have accepted that the empty vacuum of space is indeed mostly empty. Even scientists in the 1900’s laughed at the previous ideas of space being made out of aether. Could Aristotle and René Descartes have been right about the fabric of the cosmos? 2

In 1917, the theoretical physicist Albert Einstein had a dilemma while working on the General Theory of Relativity. He assumed that the Universe was static and was not contracting but his own equations resulted in the Universe eventually collapsing on itself. To complete the General Theory of Relativity, Einstein included the symbol λ (lambda) in his equation to counteract the contraction of the Universe. He did not know what force λ was coming from but the equation required some opposing force so that the Universe doesn’t collapse into itself. 12 years after writing the General Theory of Relativity, Edwin Hubble observed that the Universe was expanding. Upon finding out that the Universe was not static, Einstein admits that including λ into the General Theory of Relativity was one of his biggest blunders.3

In the 1930’s Fritz Zwicky studied the famous Coma Cluster. Galaxy clusters are large amounts of stars and galaxies that are relatively close to each other and are bound together by gravitational forces. Zwicky calculated that the collective gravity of these galaxies alone could not account for them maintaining their cluster status. In fact, he realized that no observed galaxy cluster in the Universe has sufficient gravitational forces to keep the cluster together. Since astronomers regularly observe star clusters, Zwicky observed a discrepancy. He proposed that the galaxies were held together by an additional force which he called Dunkle Materie, or in English, dark Matter. Was Einstein and Zwicky correct about strong and mysterious opposing forces in the Universe? 4

The pictures above are a representation of over 80 galaxy clusters. The data collected from these observations were used to determine the effect of dark energy on galaxy clusters over time. The majority of the matter in galaxy clusters can be observed using x-ray telescopes. (Image: © NASA/CXC/SAO/A.Vikhlinin et al.) 5

In 1998, dark energy was discovered by American and Australian astronomers. After measuring and comparing distant supernovae, it was determined that the Universe is not only expanding, but accelerating. Over the last two decades, many reputable teams of astronomers have agreed that the Universe is indeed expanding. It requires a tremendous force for the Universe to accelerate in its expansion and the force driving this is dark energy. 5

Zwicky and Einstein have both been proven correct in their hypothesis about alternate forces driving the Universe. To account for the large role that dark energy and dark matter play on the Universe it is believed that these two substances make up the majority of the Universe. It is estimated that dark energy accounts for 68% of the total energy and mass of the Universe and that dark matter accounts for 27% of the mass of the Universe. This means that Earth and the over 100 billion galaxies only account for about 5% of the total matter in the Universe. 6

Although there are currently more questions than answers about dark matter and dark energy, the evidence remains consistent that there is an overwhelming force that accelerates the expansion of the Universe which we call dark energy. Dark matter on the other hand holds galaxies together that would have otherwise broken apart due to insufficient gravitational forces. Contrary to popular belief that the Universe is filled mostly with empty space, it looks like Aristotle and René Descartes may have been right about the fabric of the cosmos having a mass and energy. Zwicky was correct about his hypothesis on dark matter. It turns out that Einstein’s biggest blunder was not that he included λ in the General Theory of Relativity, but his biggest blunder was thinking that including λ was his biggest blunder. Because after all, Einstein was correct in an additional unseen force of the Universe.

References

1 ScienceAlert (sakkmesterke/iStock). (2020). What Is Dark Matter? Retrieved July 12, 2020, from https://www.sciencealert.com/dark-matter

2 Pilkington, M. (2004, February 12). Filling space: The aether. Retrieved July 12, 2020, from https://www.theguardian.com/science/2004/feb/12/research.science

3 Texas A&M University. (2007, November 28). Einstein’s Biggest Blunder? Dark Energy May Be Consistent With Cosmological Constant. Retrieved July 12, 2020, from https://www.sciencedaily.com/releases/2007/11/071127142128.htm

4 BARTUSIAK, M. (2018). Ch. 16 Dark Matters. In DISPATCHES FROM PLANET 3: Thirty-two (brief) tales on the solar system, the milky way, and beyond (pp. 115–121). Place of publication not identified: YALE UNIV Press.

5 Bryner, J. (2008, December 16). Mysterious Dark Energy Confirmed By New Method. Retrieved July 12, 2020, from https://www.space.com/6230-mysterious-dark-energy-confirmed-method.html

6 Nagaraja, M. (2020). Dark Energy, Dark Matter. Retrieved July 12, 2020, from https://science.nasa.gov/astrophysics/focus-areas/what-is-dark-energy