It’s Everywhere Around You, But We Don’t Know What It Is…
“Dark energy is perhaps the biggest mystery in physics.”- Steve Allen
While it is everywhere in the universe, from the empty space in your closet to the great vastness of space, we have no clue what dark energy actually is. Making up for 68% of the known universe, dark energy is one of the biggest and the most important mysteries of the universe. We know the number because of the effect it has on the expansion of the universe.
Likewise, with dark matter, dark energy makes up for the majority of the universe. While it may be confusing to some, dark energy is not to be confused with dark matter. Although astronomers have been conducting countless research on this topic, there isn’t a lot to look for when you don’t even know what it is you are looking for.
Dark Energy
Unlike what the name may suggest, dark energy is not actually “dark,” since it doesn’t interact with light. We don’t know what it looks like so astronomers gave it the name “dark energy” because it is hidden and unknown. To start, dark energy is a name given to a mysterious force, causing the universe to be accelerating in its expansion over time, rather than slowing down.
Because of the mysterious expanding force, the universe is expanding faster today than it did billions of years ago. Prior to this data being discovered, astronomers until the late 1990s believed the universe did not have enough mass to the big crunch. This idea is now debunked, as the universe is alarmingly growing and acquiring more mass as it amplifies.
Today, there have been planned space missions, current and future, along with ground-based surveys. This includes NASA’s orbiting WFIRST telescope and the international Dark Energy Survey, based in Chile, which investigate the properties and nature of dark energy.
The Big Crunch is a hypothetical scenario, which describes the final fate of the universe. According to this theory, the expansion of the universe eventually reverses and recollapses on itself. This would cause the cosmic factor to reach zero. Followed immediately after this event, the reformation of the universe will begin, starting another Big Bang.
Research on Dark Energy
Due to the data obtained by the 2dF Galaxy Redshift Survey and the Sloan Digital Sky Survey, it seemed, now, to be confirmed that the universe would expand forever, although, the universe’s own mass and gravity tried to pull it back.
In 1998, a survey of Type 1A supernovae showed the very first sign of a revolutionary discovery about to be made. To calculate the distance in the celestial heavens above, the massive explosions of dying giant stars are extremely useful to astronomers, due to the output of the same amount of light from them.
With eight telescopes set up around the world to observe, the astronomers’ main goal was to calculate the expansion rate of the universe using the distance of Type 1A supernovae.
This research went on to prove the explosion that occurred when the universe was the only ⅔ of its current age, of distant supernovae, were much fainter than they should’ve been. They were, therefore, much farther away. If these ideas were correct, this indicated that the universe had expanded much faster than it should have.
Type 1A supernovae is a type of supernovae that occurs in a binary star system, in which one of the stars is a white dwarf, the other can be any other star, from a giant, to an even smaller white dwarf.
Observations
As these observations were recreated by other astronomers, it was becoming clearer that, contrary to the common belief of the universe slowing down its expansion, it was actually accelerating.
As one may expect, the expansion of the universe had been slowing down, until seven or eight billion years after the big bang, when all of a sudden a mysterious anti-gravity force started dominating.
This force overcame the brakes that gravity had placed on the expansion of the universe. This reversed the stagnation of the expansion and instead caused it to accelerate. As we now know, the force responsible is dubbed by scientists as dark energy.
Einstein’s Theory
Albert Einstein was the very first person to realize that empty space is not nothing. The very first property discovered by Einstein is that space can come into existence.
One aspect of Einstein’s theory of gravity proposed the idea of the possibility of “empty space” possessing its own energy. This energy would not weaken as space expands, as it is property of space itself. As more space comes into existence, the “energy of space” would also appear.
This so-called dark energy seemed to match Einstein’s cosmological constant, sometimes known as the fudge factor, described by Einstein himself later, as a significant slip-up in his professional life.
He had initially detested the idea of an expanding universe, and much rather preferred the one in which the universe was stagnant and unchanging, popular in the early 20th century.
He then went on to invent an anti-gravity force, undefined of its origin, to thwart the observed expansion of the universe, resulting in a non-expanding one, nor contracting one. As this idea was not supported by observations, he withdrew this theory.
While dark energy does somewhat behave like Einstein’s anti-gravity force, its nature and its origins remain to be one of the greatest mysteries ever faced in astronomy. The greatest one being why dark energy started to dominate other forces only at a certain point in time, billions of years after the big bang. Why wasn’t it there all along?
Higgs Field
In recent years, one idea, which suggests dark energy resembles a force known as a “quintessence,” relative of the Higgs Field, has gained ground. So far, there has been no evidence in the observational study to counteract or to support this idea.
Discovered in 2012, the Higgs field of energy is thought to exist in every part of the universe. It is accompanied by a particle known as the Higgs boson, used by the field to repeatedly interact with other particles such as electrons.
To give an analogy, imagine you are in a large room with just BTS fans. When their manager walks in, the fans may not show much interest, and he or she may easily be able to get past the crowd without much difficulty, but when the members walk in, there is a huge difference.
For them, it is much difficult to get past the crowd, compared to the manager. As they try to get to the other side of the room, their fans will crowd them and try and talk to them.
This is kind of how the Higgs field works. While the BTS members don’t change anything, they do affect how the crowd interacts with them. Higgs field works in the same manner. It isn’t the partciles that change in it, but how they interact with it.
If the particle is attracted to the Higgs boson, then it clusters up, while if it isn’t, then it doesn’t come closer, and instead tries to avoid it. It isn’t the Higgs boson particles that are changing, but rather how it interacts with the particles while it passes through them.
The Higgs boson does not essentially give other particles mass. The particle is an estimated display of a field (the Higgs Field) which generates mass through its interaction with other particles.
The particle, Higgs boson, is important to the Standard Model because it indicates the existent of the Higgs field. This discovery has been creating stirs in the Physics community.
In simple terms, quintessence, in Physics, is a hypothetical form of dark energy. It serves as an explanation of the observation of the expanding of the universe at an accelerating rate.
Dark energy is one of the profound topics in astronomy. Although dark energy makes up the largest part of the universe, we know very little about it. As to whether or not this expansion will continue forever, scientists are clueless. If the expansion does continue to accelerate, it would lead to the scenario where the expanding force will take over the forces that keep the universe intact, and tear all matter in the cosmos apart, making the nightmare theory of the Big Rip, come alive. This has left many scientists and astronomers baffled and wanting more explanation, hence the research continues. Dark energy is one of the greatest mysteries of the universe and to find out what exactly it is, might just be the key to unravelling the universe’s many kept secrets.
TL;DR
- Dark energy makes up for 68% of the universe
- Dark energy is not actually “dark.” It is a name given to the energy that is hidden and is unknown.
- The universe is accelerating rather than slowing down its expansion and it is expanding faster than it did billions of years ago.
- Only after seven or eight billion years after the big bang, did the dark energy start to show.
- Einstein discovered that empty space is actually not empty at all and is not nothing.
- Dark energy may contribute to the end of the universe in a Big Rip.
About the Author!
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