Dark Energy and Dark Matter

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Dark energy and dark matter are intriguing forces in the universe. Much is still to be learned, but it is believed that they both have been in existence since the beginning. According to NASA, the universe is comprised of 70% dark energy, 20% dark matter, and 5% visible matter – all seen (Netting). Following is a look at dark matter and dark energy, their relationship, and current developments in their continued study. Dark Matter In 1933, astronomer Fritz Zwicky discovered evidence of dark matter when he identified that the actual mass of stars in the Coma cluster of galaxies was only one percent of that necessary to keep the galaxies within the cluster’s gravitational pull (Reis, “Dark Matter”). This indicated that there was more mass present than what was visible (Reiss, “Dark Matter”). Dark matter is identified by its effects on visible matter. According to the Hobby-Eberly Telescope Dark Energy Experiment (HETDEX), “dark matter attracts … [it] releases no detectable energy, but … exerts a gravitational pull on all the visible matter in the universe” (Benningfield, “Dark Energy vs. Dark Matter”). While observing the Milky Way, astronomers Vera Rubin and W. Kent Ford confirmed the existence of dark matter during the 1970s when they discovered stars on the galaxy’s outer rim orbiting at the same speed as those near the center (Reis, “Dark Matter). Under the existing laws of gravity, stars at the outer rim would have to orbit at a slower rate than those near the center in order to stay in the galaxy’s rotation (Reiss, “Dark Matter”). This indicated the existence of an unseen force that was creating a gravitational pull. During the past 20 years, X-ray telescopes have also identified the existence of unseen matter in the form of hot gas within clusters of galaxies (Reiss, “Dark Matter”). The components of dark matter are not easily detectible and remain a mystery
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