The most popular theory to explain how the universe began is the Big Bang Theory. In short, it argues that the universe as we know it began with an unimaginably hot and dense single point that expanded and stretched over the course of the following 13.7 billion years to become the still-expanding cosmos that we know today, first at unfathomable speeds and subsequently at a more measured rate.
Since astronomers are currently unable to physically see back in time to the universe’s creation, a large portion of our knowledge of the Big Bang explosion is derived from mathematical formulas and models. Nonetheless, the “echo” of the expansion is visible to astronomers thanks to a phenomenon called the cosmic microwave background.
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Even though the Big Bang theory is accepted by most astronomers, some theorists have proposed explanations other than it, like everlasting inflation or an oscillating cosmos. Everything in the universe was compressed into a very tiny singularity, a point of infinite heat and density, about 13.7 billion years ago.
Our cosmos started to expand explosively at an accelerated rate, surpassing the speed of light. This cosmic inflationary phase lasted only a few hundredths of a second, or roughly 10^-32 of a second, based on scientist Alan Guth’s 1980 theory, which fundamentally altered our understanding of the Big Bang.
The more conventional theories of the Big Bang gained traction when cosmic expansion abruptly and mysteriously ended. Known as “reheating,” a deluge of matter and radiation started to fill our universe with the elements we recognize today: atoms, particles, and the material that would eventually form stars and galaxies, among other things.
According to NASA, all of this occurred at the initial instant of the universe’s creation, when the temperature of everything was still incredibly hot—roughly 10 billion degrees Fahrenheit (5.5 billion degrees Celsius). Now, a wide variety of fundamental particles, including protons, neutrons, and electrons, were present in the universe; these would eventually serve as the building blocks of everything that exists today.
Since it was unable to contain visible light, this early “soup” would have been invisible to the naked eye. “The free electrons would have caused light (photons) to scatter the way sunlight scatters from the water droplets in clouds,” said NASA. However, over time, these free electrons came into contact with nuclei and formed atoms that were either neutral or had an equal amount of positive and negative electric charges.
This occurred roughly 380,000 years after the Big Bang and made light visible for the first time. The cosmic microwave background (CMB) is the official name for the light that is sometimes referred to as the “afterglow” of the Big Bang. Though Ralph Alpher and other scientists first predicted it in 1948, it wasn’t discovered until nearly 20 years later by mistake.
According to a NASA article, Arno Penzias and Robert Wilson of Bell Telephone Laboratories in New Jersey made this unintentional discovery in 1965 when they were constructing a radio receiver and detected higher-than-expected temperatures. When they cleaned up the mess and killed the pigeons, the anomaly continued to exist. Initially, they believed the abnormality was caused by pigeons trying to roost within the antenna and their waste.
Concurrently, a group at Princeton University under the direction of Robert Dicke was searching for proof of the CMB when they realized Penzias and Wilson had discovered it through their peculiar observations. In 1965, the two organizations each had publications published in the Astrophysical Journal.
Has the Big Bang Theory been Proven?
We really can’t say anything about this in general. We are limited to stating that the Big Bang hypothesis is strongly supported by evidence and that the hypothesis passes every test that we run on it. Scientists can only state that the evidence supports a theory with a certain degree of confidence, which is always less than 100%, while mathematicians can prove things.
In summary, all of the observational data that we have acquired is in line with the Big Bang Theory’s predictions in response to a slightly different query. The following three observations are crucial:
1) The Hubble Law indicates that when there is uniform expansion in all directions, distant objects are moving away from us at a rate proportionate to their distance. This suggests a past in which things were more closely spaced.
2) The cosmic microwave background radiation’s characteristics (CMB). This demonstrates that there was a change in the universe from an ionised gas (plasma) to a neutral gas. A transition like this suggests that the early cosmos was hot and dense and cooled as it expanded. This change took place roughly 400,000 years after the Big Bang.
3) The proportional amounts of light elements (Deuterium, He-4, He-3, and Li-7). These were created in the initial moments following the Big Bang during the Big Bang Nucleosynthesis (BBN) era. Their abundances reveal that the universe was extremely hot and dense at some point in the past (the conditions during the formation of the CMB, on the other hand, were merely standard hot and dense; the temperature difference between the BBN and CMB events is around a million times larger).
Is There Any Occurrence that Contradicts the Big Bang Theory?
Not that I am aware of. The simplest Big Bang model has significant shortcomings, but those can be overcome by referring to a physical process that maintains the Big Bang Theory’s fundamental tenets. In particular, the cosmos does not appear to have any curvature, the CMB temperature is constant throughout, and the density fluctuations predicted by quantum mechanics do not result in the formation of galaxy clusters that are currently the proper size and shape. The Big Bang Theory, which includes the inflation theory, provides a solution to these three problems.
When was the Big Bang Theory Established?
Who thought up the idea?
Actually, Hubble organized the observations. The body of evidence kept growing, particularly after the CMB was discovered in the 1970s. Astronomer Fred Hoyle coined the phrase “Big Bang” in the late 1940s, and it gained popularity in the 1970s.
Since the Big Bang cannot be directly observed, scientists have been attempting to determine alternative ways to “see” it. In one instance, using a large supercomputer to simulate 4,000 copies of the existing universe, cosmologists are pushing back time to reach the first instant following the Big Bang.
Wrapping Up the Journey of the Big Bang Theory
The Big Bang Theory: The universe is infinite, and so are the possibilities of making new discoveries. Is Earth the only habitable planet? Are we the only known life in this whole universe and beyond? Or is there extraterrestrial life elsewhere in some parallel universe? All these questions keep us going on with exploring the cosmos further. I am sure you would have enjoyed going through this article. Stay tuned to Digital Gabbar for more knowledgeable articles. Get, set, space!
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