THE FATE OF THE UNIVERSE Phantom Energy and Cosmic Doomsday: Adapted by Alexandre Ramirez

Fig A: History of the universe: In the image below we see a timeline of the universe from How will the Universe end? the beginning to now. Notice how the stars and galaxies are close together on the left side and The End of the Universe: Phantom Energy further apart on the right side. This spreading apart is due to the expansion of the universe that Scientists havethreedifferent theories as to how the universe will end. many speculate is caused by a force called dark energy. The first idea is that gravity will bring all matter in the universe into one The reason that some scientists believe that dark energy is in space causing a Big Crunch. The second, and more scientifically fact phantom energy is in order to satisfy theories about supported theory, is that the universe will expand at an increasing rate quantum gravity- the behavior of atoms in large gravitational forever causing the stars and galaxies to spread out over immense field. If dark energy is truly phantom energy then over billions distances (See Fig A). The third new theory is that the universe will of years phantom energy would expand the universe at a rate expand at such an immense rate that the expansion will eventually tear that is greater than exponential. As a result, after several billion everything apart in the universe in an event called the Big Rip. years the expansion of the universe will decrease the size of the visible universe. Eventually, near the end of time, the strength Scientists are unsure as to how the universe is expanding and how its of expansion will be so strong that objects that are rate of expansion will change over time. Some scientists believe that gravitationally bound to each other (such as the sun and the expansion happens naturally in the universe, and others believe that a Earth) will be separated from one another. About half an hour force called dark energy is responsible for it. The nature of dark energy is before the end of the universe, the Earth itself will explode as heavily debated with certain scientists believing that dark energy has a the strength of gravity will be less than that of phantom energy. constant value, while others believe the strength of dark energy Fractions of a second before the end of the universe molecules is reaching that constant value (quintessence) and others believe it has Fig B: The Universe under phantom energy: In the image and then atoms will be torn apart resulting in a Big Rip. (See Fig a value that is greater than the constant (phantom energy) below, A full timeline of the universe is given, from the Big Bang, to B) Conclusion The Universe without dark energy the Big Rip In the cases of quintessence and a universe without dark If the universe expands under a constantly increasing rate, then in the energy, the universe’s expansion leads to changes in what we far future the universe will not only be much bigger itself, but the will see in the night sky and the physical distances between our visible universe will expand. That is to say that we will see more own galaxy’s neighborhood and the rest of the universe. In the galaxies in the sky, granted they will be further away. Over vast case of phantom energy, not only does the visible universe stretches of time the universe will become increasingly cold and vacant shrink and the general universe grow, but at a certain point of time deep into the future, everything within the universe is The Universe under Quintessence torn apart in an event called The Big Rip. What is important to understand however, is that these three ideas as to the nature In the quintessence model of the universe, the strength of dark energy of dark energy lack sufficient scientific data and must be taken is between the minimum of what it needs to be in order for the universe with a grain of salt. Though they are pretty neat! to beexpanding at a constantly increasingrate and the dark energy constant that is used under the theory of constant expansion. As a result Works Cited Caldwell, R. R., Kamionkowski, M., & Weinberg, N. N. (2003). Phantom Energy: Dark Energy of this, the visible universe (the range of stars that we see in the withw<−1Causes a Cosmic Doomsday. Physical Review Letters, 91(7). sky) will shrink and the universe itself will continue to grow. Galaxies https://doi.org/10.1103/physrevlett.91.071301 that we see today will no longer be visible in the far future. However, NASA. (n.d.). Big Bang Explosion. Retrieved from https://astro-interest.com/2014/09/origin- of-elements-in-the-universe-an-evolution-after-big-bang- explosion/ galaxies that are relatively close to the Milky Way will remainclose due Siegel, E. (2019, February 7). Dark Energy May Not Be A Constant, Which Would Lead To A to the strength of gravity at near distances. The universeas a Revolution In Physics. Retrieved October 13, 2019, from Medium wholewon’tbe explorable, but our galactic neighborhood, that is the website: https://medium.com/starts-with-a-b ang/d ark- energy-may-not-be- a-constant-which- would-lead-to-a-revolution-in-physics-9f399f9aa8eb galaxies that are relatively near to our own, will be.