The Big Bang Theory is the main explanation as to how the universe began. In its simplest explanation, it states that the universe started with a small singularity, which then inflated over the next 13.8 billion years to create the cosmos that we know today. At the moment, we don’t have the instruments to look back at the universe’s creation, so much of our understanding of the Big Bang Theory is mostly mathematical formulas and models. However, astronomers can study the expansion through a phenomenon called the "Cosmic Microwave Background". The cosmic microwave background is electromagnetic radiation that is left from the early stages of the universe, which is also known as “relic radiation.” In simpler terms, it is distant cosmic background radiation filling all space. Although most of the astronomical community agree with the Big Bang Theory, some theorize an alternate explanation besides the Big Bang, such as eternal expansion or an oscillating universe, but since there are no tools to actually determine the origin, these are all just hypotheses.
At the first second the universe was created, the surrounding temperature was 10 billion degrees Fahrenheit, or 5.5 billion degrees Celsius, based on NASA’s studies. The cosmos had a large array of fundamental particles, which include protons, neutrons, and electrons. These either decayed or combined as the universe got cooler. This would have been impossible to look at because light couldn’t carry inside it. NASA said that “The free electrons would have caused light (photons) to scatter the way sunlight scatters from the water droplets in clouds.” Over time, the free electrons met with nuclei and created neutral atoms. This allowed light to shine through ~380,000 years after the Big Bang. This early light, which is sometimes called “afterglow” of the Big Bang, is known more properly as cosmic microwave background.
This was first predicted by a group of scientists in 1948, but the most known one was Ralph Alpher. This was actually found by accident ~20 years later. This accident was found by Arno Penzias and Robert Wilson from Bell Telephone Laboratories in Murray Hill, New Jersey. They were building a radio receiver in 1965 but were picking up higher temperatures than expected. They first thought it was due to the dung of the pigeons, but after fixing that problem, the temperatures were still the same. At the same time, a Princeton University team, which was led by Robert Dicke, was trying to find evidence of the cosmic microwave background, then realized that Penzias and Wilson had stumbled upon it already. Each team published papers in the Astrophysical Journal in 1965.
The cosmic microwave background has been observed on many missions, one of the most famous being NASA’s Cosmic Background Explorer (COBE) satellite, which mapped the sky in the 1990s. Several other missions have followed in the footsteps of COBE, such as the BOOMERanG experiment, Balloon Observations of Millimetric Extragalactic Radiation and Geophysics, NASA’s Wilkinson Microwave Anisotropy Probe, WMAP, and the European Space Agency’s Planck satellite. Planck’s observations were first released in 2013 and mapped the background in unprecedented detail and showed that the universe was older than previously thought. Rather than 13.7 billion years old, the universe is 13.82 billion years old. The maps caused a rise of new mysteries, however such as why the Southern Hemisphere is slightly warmer than the Northern Hemisphere, The Big Bang Theory states that cosmic microwave background would be mostly the same no matter where you look at. Examining the cosmic microwave background also provides astronomers with information as to the configuration of the universe. Researchers think most of the cosmos is made up of matter and energy which can’t be sensed with conventional instruments, which leads to the names dark matter and dark energy. Only 5% of the universe is made up of matter such as planets, stars, and galaxies.
Overall, the Big Bang Theory is the main explanation for the creation of the universe. Astronomers use the cosmic microwave background to help their understanding of the creation of the universe as these are leftovers from the early stages of the universe. The universe’s surrounding temperature was 10 billion degrees Fahrenheit or 5.5 billion degrees Celsius based on NASA’s studies. The cosmos had a large array of fundamental particles like protons, neutrons, and electrons. There was, and still is, very little known about the creation of the universe, but there are many great hypotheses made by the astronomic community.
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By: Zubin Sidhu
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References: Howell, Elizabeth. “What Is the Big Bang Theory?” Space.Com, 7 Nov. 2017, www.space.com/25126-big-bang-theory.html.
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