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Astronomers believe the Universe is expanding at an ever-increasing rate by the enigmatic force that is known as dark energy. Though, new evidence has been found that may counter this original theory. Astronomers have found types of supernovae are are extraordinarily diverse, which backs up the claim that the Universe’s expansion is actually slowing down. These results have cosmological implications to many questions that have baffled scientists for years, such as at what speed has the Universe been expanding ever since the occurrence of the Big Bang.
Ever since scientists created the Big Bang Theory, they studied stellar bodies as they travel through the Universe to try and unearth more evidence about how this phenomenon acts. As previously stated, dark energy is said to be to arbiter of expansion. Dark energy is the counter-equivalent of normal energy. Just as gravity pulls mass towards a central point of force, dark energy does the exact opposite, it pushes mass away. Thus, creating the entropy that led to the Universe’s expansion, following the Big Bang.
The way in which scientists have found this new discovery is by observing different types of supernovae. Peter Milne, an astronomer at the University of Arizona, along with his team, have determined that supernovae, violent, self-destructing stars, are much more diversified than previously thought. In decades past, scientists looked to supernovae as a cosmic point of reference to determine the dimensional characteristics of the Universe, such as size and depth. Beforehand, it was believed that the speed at which light from the supernovae reached the Earth was a constant. However, these conclusions have now been proved false, due to the fact that these exploding stars vary in their intensity. Therefore, the Universe’s expansion speed could be proved to be much slower than what was previously calculated.
This novel finding goes back to dark energy. Milne’s team discovered that some supernovae were, in fact, less intense, and had moved farther away from the Earth than what was originally predicted. This showed that the expansion speed of the Universe was decreasing, leading to the fact that dark energy was the cause. This leads scientists to believe that there is less dark energy than what is currently theorized. According to current calculations, dark energy makes up 73 percent of the Universe. Since there is much more of it than any other force, it pushes matter away, causing cosmic expansion.
The new discovery has now led scientists to re-examine data about supernovae. They have now agreed to put the destructive stellar bodies into two categories: one where the supernova further away from the Earth and in the majority, and one where the star is a minority and is closer to the Earth. They categorized these by their observations from different types of light coming from the supernovae in both visible and ultraviolet (UV) light.
These stars have been used to measure distance in the Universe, regarding their location when they violently exploded. Thus, creating reference point astronomers can use to measure the speed of cosmic expansion. Though, since it has now been found that all supernovae do not act as a constant, the Universe’s expansion could be slower than what was once thought.
By Alex Lemieux
Photo by Harvard-Smithsonian Center for Astrophysics – Flickr License