WIKI: The Origin of the Universe PDF

WIKI: THE ORIGIN OF THE UNIVERSE The origin of everything has long been a major interest for humankind, including the origin of animals, humans, plants, planets, and stars. The most fundamental of all origins appears to be the origin of the universe as a whole – of all that exists. Perhaps this...

WIKI: THE ORIGIN OF THE UNIVERSE The origin of everything has long been a major interest for humankind, including the origin of animals, humans, plants, planets, and stars. The most fundamental of all origins appears to be the origin of the universe as a whole – of all that exists. Perhaps this is why the existence of the cosmos, as well as its origin and nature, have been a topic of discussion in nearly all civilizations and cultures. In ancient times, people attempted to explain natural happenings as the consequence of gods and spirits' actions. This involves the topic of how the world, or more accurately, the Universe, came to be. The Biblical narrative of creation in the book of Genesis, which claims that God created everything in six days, is a prominent idea for the origin of the universe. (Image Source: Big Bang Theory vs Bible Timeline Chart - Short. (2019). Utreon. https://utreon.com/v/CkqI46HVPUQ) In modern astronomy, there are four well-known theories that hypothesize the origin of the universe, namely: Big Bang Theory Steady State Theory Oscillating Universe Theory Let us discuss each theory one by one. A. BIG BANG THEORY The Big Bang Theory states that the universe, about 13.8 billion years ago, started as a “singularity”—an area predicted to be in the core of a black hole with a very high temperature and density, which compressed matter with its intense gravitational pressure from which it has cooled and expanded since. ______________________________________________________________________________________________ This document contains proprietary and confidential information. Reproduction, redistribution, or forwarding to any third party, in whole or in part, is strictly prohibited unless made with prior written consent from APEC Schools. Violation or noncompliance shall be dealt with according to law. Page 1 of 6  (Image Source: BIG BANG CENTRAL. (2018). BIG BANG CENTRAL. http://www.bigbangcentral.com/theory_page.html) In 1922 to 1924, Edwin Hubble painstakingly developed a series of nebulae distance indicators using the 100-inch Hooker telescope at Mount Wilson Observatory in California. Edwin Hubble, then a thirty-five-year-old scientist, presented a paper in January 1925 that proved conclusively that some of the faint stellar objects were much too distant to be part of our galaxy and were in fact, "galaxies outside the Milky Way". In 1927, George Lemaître, a Belgian physicist and Roman Catholic priest, interpreted Friedman's equations and proposed that the recession of nebulae was due to the "expansion of the universe". (Back then, the word nebulae meant galaxies outside the Milky Way; today nebulae means large clouds of gas and dust.) However, both Friedman and Lemaître were mostly dismissed, even by Albert Einstein. In 1929, Hubble discovered a correlation between "nebulae distance and recession velocity" which meant that indeed "the universe was expanding", a shock to most scientists of that time. Although the Big Bang is often described as an "explosion", that's a misleading image. In an explosion, fragments are flung out from a central point into a pre-existing space. If you were at the central point, you'd see all the fragments moving away from you with roughly the same speed. But the Big Bang wasn't like that. It was an expansion of space itself – a concept that comes out of Einstein's equations of general relativity ______________________________________________________________________________________________ This document contains proprietary and confidential information. Reproduction, redistribution, or forwarding to any third party, in whole or in part, is strictly prohibited unless made with prior written consent from APEC Schools. Violation or noncompliance shall be dealt with according to law. Page 2 of 6  but has no counterpart in the classical physics of everyday life. It means that all the distances in the universe are stretching out at the same rate. This overall narrative of the universe's history, in accordance with the big bang theory, is supported through numerous lines of observational evidence, which include: ○ (1) the universe's expansion, ○ (2) the existence of the cosmic microwave background radiation, ○ (3) the abundances of the lightest chemical elements, in particular hydrogen and helium, and ○ (4) the age of the oldest-known stars. You may watch The Big Bang Theory - Explained (expanding universe theory) to further learn about this theory. B. STEADY STATE THEORY The Steady-State model states that the density of matter in the expanding universe remains unchanged over time because of the continuous creation of matter. In other words, the observable Universe essentially remains the same regardless of time or place. (Image Source: Eternal Big Bang. (2015). Creation. https://creation.com/eternal-big-bang) ______________________________________________________________________________________________ This document contains proprietary and confidential information. Reproduction, redistribution, or forwarding to any third party, in whole or in part, is strictly prohibited unless made with prior written consent from APEC Schools. Violation or noncompliance shall be dealt with according to law. Page 3 of 6  This theory was developed in 1948 by Fred Hoyle (1915-2001), Herman Bondi (1919-2005), and Thomas Gold (1920-2004) as an alternative to the Big Bang to explain the origin and expansion of the Universe. At the heart of the Steady State theory is the Perfect Cosmological Principle. This states that the Universe is infinite in extent, infinitely old and, taken as a whole, it is the same in all directions and at all times in the past and at all times in the future. In other words, the Universe doesn’t evolve or change over time. If the Steady State theory were true, then an observer would measure the same values of: ○ the average density of the Universe, ○ average distance between galaxies, ○ average brightness of galaxies, and ○ how the speed that galaxies are moving away varies with their distance in all regions of the Universe at any time in the past or in the future. The Steady State theory was very popular in the 1950s. However, pieces of evidence against the theory began to emerge during the early 1960s. These included the discovery of bright radio sources (aka. quasars and radio galaxies) which were discovered in distant galaxies but not those closest to us – indicating that many galaxies became “radio-quiet” over time. Another major argument against the Steady State Hypothesis was the discovery of the Cosmic Microwave Background (CMB) in 1964, which the Big Bang model predicted. You may watch Steady State Theory - Explaining Science to further learn about this theory. C. OSCILLATING UNIVERSE THEORY The Oscillating Universe Theory, also referred to as the Pulsating Theory, discusses that the universe is expanding and will contract once all the energy after the Big Bang is used up. ______________________________________________________________________________________________ This document contains proprietary and confidential information. Reproduction, redistribution, or forwarding to any third party, in whole or in part, is strictly prohibited unless made with prior written consent from APEC Schools. Violation or noncompliance shall be dealt with according to law. Page 4 of 6  (Image Source: OSCILLATING UNIVERSE THEORY. (2016, September 11). [Video]. YouTube. https://www.youtube.com/watch?v=dW4IL-8qi0o) This theory, proposed by Richard Tolman, can be described as the combination of the Big Bang and the Big Crunch. The Big Crunch occurs when the universe expands and eventually reverses, then collapses, causing a singularity or the formation of another Big Bang. The Oscillating Universe Theory suggests that once the universe reverses and attains the point of singularity, another universe will be born. This is referred to as the Big Bounce. Tolman theorized that the universe may be first in the cycle and could be a result of a previous Big Bounce event. The probability of a Big Bounce, or even a Big Crunch for that matter, is however, becoming negligible. The most recent measurements of the CMBR or cosmic microwave background radiation show that the Universe will continue on expanding and will most likely end in what is known as a Big Freeze or Heat Death. This theory was popular in the 1960’s and 70’s, but has currently fallen out of favor. One reason is that all recent data shows that the universe is not closed and consequently will expand forever. Another reason is that this theory ignores the second law of thermodynamics, which requires usable energy to continually decrease and for the universe to become more random and disorganized. A third reason is that it really doesn’t provide an explanation of the initial creation; rather, it only pushes it back further in time. You may watch Cosmology, Critical Density, Big Crunch, Oscillating Universe, Accelerating Expansion, Dark Energy to further learn about this theory. ______________________________________________________________________________________________ This document contains proprietary and confidential information. Reproduction, redistribution, or forwarding to any third party, in whole or in part, is strictly prohibited unless made with prior written consent from APEC Schools. Violation or noncompliance shall be dealt with according to law. Page 5 of 6  References: Cosmology, Critical Density, Big Crunch, Oscillating Universe, Accelerating Expansion, Dark Energy. (2015, May 7). [Video]. YouTube. https://www.youtube.com/watch?v=JDb4BOEeKWw Steady State Theory. (2020, October 1). [Video]. YouTube. https://www.youtube.com/watch?v=aUmQjmw4jhE The Big Bang Theory - Explained (expanding universe theory). (2016, December 13). [Video]. YouTube. https://www.youtube.com/watch?v=pivS9HzattI The Steady State Theory. (2015). Explaining Science. https://explainingscience.org/2015/07/25/the-steady-state-theory/ What about the Oscillating Universe? (N.D) What Is the Big Bang? (2022). NASA Science. Space Place. https://spaceplace.nasa.gov/big-bang/en/ What is the Big Bang Theory? (2022). Space. https://www.space.com/25126-big-bang-theory.html What is the Oscillating Universe Theory? (2009). Universe Today. https://www.universetoday.com/38195/oscillating-universe-theory/#: What is the Steady State Theory? (2020). Universe Today. https://www.universetoday.com/145060/what-is-the-steady-state-hypothesis/ ______________________________________________________________________________________________ This document contains proprietary and confidential information. Reproduction, redistribution, or forwarding to any third party, in whole or in part, is strictly prohibited unless made with prior written consent from APEC Schools. Violation or noncompliance shall be dealt with according to law. Page 6 of 6