In past Online Alarm Clock blog posts, we have addressed the existence of time as we know it; but where did time begin?
There are many theories on the universe and how it began. We can rely on natural science and the postulations of cosmologists and physicists for the best detailed explanations for how time began. Within this blog post, you will see many scientific terms which attempt to explain to both budding scientists and novices to the subjects discussed. Further reading on these brilliant and exciting discoveries is recommended. Here at OnlineClock.net, we encourage you to keep up with the latest explanations of how time began. The universe is a fantastic subject that many continue to ponder.
Some would say that the universe has always existed, while others might say that the universe was created, and thus had a beginning. This begs the question: What was before time and space? Was it nothingness? The absence of matter or an absence of time and space is a question that the German philosopher Immanuel Kant addressed quite intensively. In Kant’s book, Critique of Pure Reason, he states that the question cannot be answered within the limits of our knowledge. Kant thought instead that time is a fundamental aspect of human perception. There are many philosophers and physicists who go into this area of time existence as not being reality, but something we perceive as a reality. Nevertheless, the universe is a physical reality to everyone. This is where we began to perceive the idea of time itself. The following theories are currently accepted, and some are being expanded upon and are pending further quantitative scientific research.
The Big Bang Theory
The first to propose a theory on how the universe began was George Lemaitre. He proposed that the universe has been expanding from one explosive moment of creation. His ideas were based on Alexander Friedman‘s solution of Albert Einstein’s relativity equations. Essentially, Einstein was the source of the Big Bang by presenting his theories of special relativity in 1905. Later, in 1915, Einstein presented the general theory of relativity, both of which were expanded on by Lemaitre and Friedman.
In 1922, Friedman added in his own solution which stated that the universe was expanding. In 1927, Lemaitre proposed the same idea. At the time, there was no evidence of the expansion of the universe, or that there was a hot beginning. They created the idea. Both of these men discarded Einstein’s original theory of a cosmology constant. Einstein had used the cosmetology constant to propose the idea that the universe was in a steady state. As noted earlier, even Einstein eventually theorized that the universe was expanding, and not in a steady state.
Lemaitre and Friedman thought that the universe was not flat, but curved. They both thought that the universe was either closed or spherical, and would eventually implode, or open and expand forever. In 1929, Edwin Hubble proposed that there were galactic red shifts that supported the idea of expansion. He stated up until his death that the red shifts he observed were apparent velocities and not actual velocities.
In 1946, George Gamow used the term Big Bang to explain the beginning of the universe. He also proposed that the universe was begun as a very hot gas. He called this gas ylem, which was made up of neutrons that decayed in protons, electrons and neutrinos. In 1948, Gamow and Ralph Alpher theorized that every element in our universe started out in a fiery explosion which spread out, cooled off and left a predicted background radiation which was not detectable at the time.
In 1964, Arno Penzias and Robert Wilson created the Cosmic Microwave Background Radiation, which is also known as the CMBR. The universe appeared to be isotropic and homogeneous. Evidence from the hot bang had been found. All Big Bang theories propose a hot beginning and an expansion, which Penzias and Wilson presented as proof through CMBR. CMBR was a monumental discovery. Penzias and Wilson later received the Nobel Prize for their work.
In 1981, Alan Guth strengthened the Big Bang theory. His theory was that the universe expanded very quickly early in its life.The expansion of the universe is consistent with the Big Bang theory, but what is the universe expanding into? In short, it expands into nothingness. Most cosmologists believe that the universe is infinite; there is nothing outside of it. Space and time only exist within the universe. This brings to mind another question: What happens when infinity expands? According to cosmologists, the answer to that is: It is still infinity, just a bigger infinity.
Time is Born
There are non-mainstream beliefs that attempt to contradict the Big Bang theory; however, they are not considered credible. They are not derived from observable data, and not peer reviewed, so they are generally tossed out as nonsensical ramblings among the fringe of the scientific community.
In summation, we are left with the following: The universe exploded, and we are left with a constant expansion, or rather an accelerating universe that has an event horizon. This is an edge beyond which we cannot see. The current distance to this horizon is 16 billion light-years, well within a range which is observable. Light emitted from galaxies that are now beyond this event horizon will never be able to reach us. The distance that currently corresponds to 16 billion light-years will expand too quickly. We will still be able to see events that happened in those galaxies before they crossed the horizon, but later events will be forever beyond what we can view.
Beyond the Big Bang Theory
The Big Bang theory is well established, but it is likely to be redefined in the future. Very little is known about the earliest moments in the beginning of the universe, or the actual point where time began. The Penrose-Hawking singularity theorems state that there is a requirement of the existence of a singularity at the beginning of cosmic time. These theorems make an assumption that general relativity is correct. However, there must be a break-down before the Universe reaches the planck temperature. Further, a correct treatment of quantum gravity may avoid a singularity. These models are briefly explained, but reading about each model will help you understand how they fit into Hawking’s theory. Perhaps you might even create your own. I know, that’s a stretch, but after reading some of these theories, it seems that anything is possible. Listed below are some of the Hawking proposals:
Hartle-Hawking no-boundary condition, which states that all of space and time are indeed finite; the Big Bang represents a limit of time, but without the need of a singularity.
The Big Bang lattice model, which states that the universe, at the moment of the explosion, consists of an infinite lattice of fermions. These fermions are smeared over the fundamental domain so that it has symmetry.
Brane cosmology models that inflate due to the movement of branes in string theory, the pre-Big Bang model, the ekpyrotic model, in which the Big Bang is a result of a collision between branes, and the cyclic model, a variant of the ekpyrotic model in which collisions happen periodically. In the latter model, the Big Bang was preceded by something Hawking refers to as the Big Crunch, where the universe endlessly cycled from one process to the other.
Chaotic inflation, which states that the inflation of the universe ends locally here and there in a random process, each point leading to a big bubble universe which expands from its own Big Bang.
Models including the proposals in the last two categories see the Big Bang as an event in a much older and larger universe, or a multiverse, and not the literal beginning.
Top-Down Cosmology
In 2003, Stephen Hawking proposed a new theory called Top-Down Cosmology. This theory states that the universe had no unique initial state, and it is not appropriate for physicists to try to formulate a theory that will predict the current configuration of the universe from one particular initial state. This Top-Down Cosmology presents a position that the present selects the past from a superposition of various different histories. The theory suggests an answer to the question: Is it certain that we will find the universe’s current physical constants because our universe selects only the pasts that led to the present conditions? Considering it in this manner, Top-Down Cosmology gives us an anthropic explanation for why we are presently in a universe which allows matter and life without engendering various numbers of universes.
This theory was attractive to many because it fits in with string theory, which is what we here at OnlineClock.net like to refer to as: The theory of everything. Most top physicists, such as the likes of Hawking, believe that string theory is the correct fundamental description of nature. They believe string theory allows for the consistent combination of quantum field theory and general relativity. It also agrees with all of the general insights in quantum gravity. Additionally, it has passed many checks on its internal consistency. Stephen Hawking states: “M-theory is the only candidate for a complete theory on the universe.” Nevertheless, other prominent physicists have criticized string theory for not providing any quantitative experimental predictions.
String theory allows for a multitude of different types of universes, but it does not select a criterion among these, and there is no explanation for why our universe exists in its current state. The next step is to find particular predictions that can be put to the test. This will validate this new theory on how time began.
The Big Rip Scenario
Robert Caldwell of Dartmouth College, has postulated a different path for the universe. His Big Rip Scenario is derived from astronomical observations which took place in the 1990s. His theory states that an unknown force, called dark energy, is responsible for the expansion of the universe. Dark energy makes up about 73 percent of the universe. If acceleration increases, there will be a point in time at which the force becomes so strong that it overwhelms gravity and the other fundamental forces. Caldwell predicts that this will happen in 20 billion years. Caldwell says that the expansion will be so swift that it will rip all matter apart. This ripping will include clusters of galaxies, stars, planets, solar systems, and eventually all matter will rip into pieces. Caldwell predicts that even atoms will be ripped apart in the final 10-19 seconds before time will end. Whether or not this scenario is true will be decided by future research. Until then, the field is open to speculation.
Physics answers many questions about the beginning of time. With the advent of so many technological advances, we have been able to look deep into the larger structure of the universe. We also have been able to look into the smaller-scale structure of matter. From the time the telescope was invented, to the invention of particle accelerators, our insights have expanded. Still, there are many mysteries yet to be solved. The contemporary models of matter, space, and time are incomplete. Our picture of the universe has holes that need explanation. For now, we will rely on current explanations for the beginning of time, while waiting at the edge of our seats for more.
Wham, bang, thank you...now set your clocks!
There are a select few who disagree with the proposals of Hawking and others who have presented a fine-tuning to the Big Bang theory. Even those who disagree have not provided scientific proof that Hawking and others are wrong about their theories of the origins of the universe, therefore their disagreements are not credible among experts in the fields of physics and cosmology.
Having discussions about how and when the universe was created is important to mankind. If we can pinpoint how the universe began and what happened after that, we can understand our origins. Understanding our origins may enable us to better understand ourselves, and perhaps improve the direction we are currently taking as a species.
We will have to wait until technology and the brilliant minds of future theorists to provide hard evidence of some of the latter theories in this post.
Time will certainly tell which of these scenarios are provable.
Time has a way of doing that, doesn’t it?
Here at OnlineClock.net, we cannot wait to see what comes next!
How Time Was Born is a post from: Alarm Clock Blog, the official blog of the original Online Alarm Clock.
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