- The first theory states that an earlier universe collapsed into the singularity that started our own universe. This idea is also known as the Big Bounce. This concept was proposed by Princeton researchers Robert Dicke and James Peebles. Some branches of this theory suggest that the universe is in a constant cycle of collapse and expand, which means our universe would eventually collapse again. However, some of the researchers proposing this theory also admit that new physics would need to be discovered for this theory to be true. Thus, since the laws of physics are said to stay true to our entire universe, this theory could be further off than the others.
- The second theory states that the universe was in a sort of sleep before some event set it into motion. This idea says that the universe was initially a small, flat, high-pressure space that was “metastable.” This means that the universe was stable until it found an even more stable state. This concept can be connected to the way a house of cards may sit perfectly forever until another force (maybe wind), came through. In the universe’s case, this “wind” came through and stopped space from being metastable. From there, the inflation of the universe began.
- The third theory states that there never was a singularity. Instead, all the energy in the universe was woven in the fabric of space. Also known as the “inflation hypothesis,” this idea states that various fluctuations in this so-called “inflaton field” led to a swell up of energy in one patch of this field, forcing that part to expand very quickly. One could picture this as a scale tipping too much towards one side. This growth would leave behind tiny imprints in the cosmic microwave background that many projects have been searching for (including the BICEP2 experiment). Most cosmologists believe that this theory has the most sound explanation regarding the universe’s low entropy.
- The final theory states that we are just one universe in a grander multiverse. Although this theory seems to be an odd idea, especially in comparison to the inflation hypothesis, it says that the elements that lead to inflation also led to the formation of other smaller universes. However, all these universes would be closed off from one another, so detecting them would require technology humanity does not possess.
As I was reading Neil Degrasse Tyson’s Astrophysics for People in a Hurry, one of Tyson’s first chapters was a thorough explanation and timeline into the birth of the universe. However, I found it interesting that the book assumed the Big Bang was the first step. There must have been something else before our universe. Thus, I began to search deeper into this question that could change how humans perceive existence altogether. Before humans ever existed, dinosaurs roamed the Earth. Before there was ever an Earth, there was a big cloud of gas and dust floating somewhere in the universe. However, before the universe, what was there? Nobody knows what happened before the Big Bang gave birth to the universe, but there are plenty of theories that could explain this impossible question. Although the few ideas differ, some greatly, they all agree that the Big Bang was an event that actually happened. The Big Bang theory suggests that the universe began as a single point of infinite gravity and density called a singularity. From here, it exploded outward, doubling and re-doubling in size at a faster rate per time interval, all in a trillionth of a trillionth of a trillionth of a second. In fact, this rate was faster than the speed of light. This was due to the fact that it was space itself expanding outward, so the laws of the speed of light did not account toward the Big Bang. Through the formations of atoms and the rapid expansion of the universe, we end up here. But the concern is everything that happened before that. In other words, what caused the initial singularity in the first place? In order to have a thorough explanation that can have scientific research to back it up, it must solve multiple problems that physicists are currently facing. The biggest problem is that the universe has a low entropy. For example, an ice cube as low entropy due to the fact that the water molecules within the ice are arranged in a certain way. However, once the ice melts, these molecules will not just rearrange themselves back into an ice cube again when the water is frozen again. In other words, everything goes in the direction of disorder, but never the reverse. But if this was the case, the makeup of the universe itself should be a uniform mix of disorganized subatomic particles. Instead, atoms formed into molecules and clouds of gas and dust formed into stars and galaxies. The only existing explanation is that the universe had a lower entropy than it does now. How this happens could be explained in one or more of the following four theories: The Theories