Theories of the Big Bang

**Ristaron** · 03-12-2007, 03:45 PM

As this subsection is the only place in the entire forum that scientific things can be discussed without religious shit, I'm posting this here.
There are a number of supposed flaws in the Big Bang theory, but they overlook an important feature about the theory:
It doesn't speculate about the actual origin of the universe, only the immediate aftermath of the event. Alan Guth, a prominent physicist and cosmologist, said “Although the classical cosmological theory is called the big bang, the theory in fact contains no description whatever of the ‘bang.’ It proposes no answer at all to the question of what banged, how it banged, or what caused it to bang. It is really a theory of the aftermath of a bang.” The big bang description of creation, Guth says, simply begins with a cosmic fireworks display already in progress — a fireball of outreaching radiation and particles.

So, to give theories about the actual origins of the universe, I have found a very useful link (from which the above quote is also derived).
[Clicky]

Here are the exerpts of the theories:
The Multiverse/Fractal-Bubble Theory
Proposed by Steven Hawking and Neil Turok.

Quote:

In Turok and Hawking's mind-bending creation model, the universe has no discrete beginning. Instead, the Cambridge scientists propose a quantum theory of the origin of the universe in which there is no distinction between time and space, and no distinct point at which either can be said to begin.

If all that seems a bit much to wrap your neurons around, consider the microscopic primordial object within which Turok and Hawking say this blending of space and time occurred. They dubbed it a “pea instanton.” And what an extraordinary pea it is, for Turok and Hawking insist that it's the seed from which the universe sprouted. They boldly argue that not only do all the laws of physics work just fine within their instanton, but those laws actually imply its existence.

Turok and Hawking’s pea instanton is attractive as a scientific theory because it’s testable. The theory makes specific predictions about the nature of the universe that sprouts from the instanton — predictions that other scientists can check by seeing how accurately they reflect the universe we actually live in. “One can predict everything about the universe from this initial instanton,” Tuork comments. “The calculations are very precise.”

But of course, precision doesn’t guarantee truth. And some cosmologists question whether the pea instanton really is getting at some universal truth. “This proposal has led to controversy,” Guth notes. “So it is too early to tell if some form of it might eventually become the accepted theory of how the universe began. In any case, it does seem rather amazing that such a far-reaching question can even be debated in scientific terms.”

The fact that scientists can have the debate at all is due in no small part to Guth’s own proposal in 1981 that the infant universe experienced a bout of gargantuan inflationary growth that led to the big bang. The physics of this inflationary universe theory, as it came to be called, is so far reaching that it explains in one stroke why the big bang happened, how matter was created, and why the universe looks the way it does in several fundamental ways.

Inflation, in turn, has spawned other theories. One in particular stands in contrast to the approach taken by Turok and Hawking in that it describes cosmic evolution as a much more complex process — and one that may have no discernible beginning at all. This theory holds that our universe was born as a tiny bubble of spacetime that inflated out of a pre-existing region and then experienced a big bang. That region, in turn, inflated out of a previous one, and so on down the line such that the original birth of spacetime — the ultimate origin of the universe — happened so far back in the past that it may well be pointless to ask how it happened.

In this view, our universe is but one component of a gigantic, fractal, multi-branching multiverse. It has been growing through a series of many big bangs for much longer than our little region of the multiversal whole. And it will continue to grow eternally into the future.

Although fundamentally different in many respects, the Turok-Hawking proposal is not necessarily incompatible with this idea, Guth points out. Although the ultimate origin of the multiverse would have occurred in the deepest mists of cosmic time, it is at least possible (if not testable) that the pea instanton was how it all got started from nothing, he says.

The Inflationary Universe Theory
Proposed by Alan Guth.

Quote:

As Guth knew, the grand unified theories, or GUTS, of particle theory predicted that the vacuum of the early universe would have been dominated by particularly energetic fields. As these primordial “scalar” fields fluctuated, their potential energy would have risen and fallen. Guth realized that it was theoretically possible for the potential energy of the fields to have gotten temporarily “stuck” at a high value. Admittedly, this was an assumption. But when Guth worked through its implications, he stumbled onto inflation.

His calculations showed that stuck scalar fields would have caused a tiny bubble of “false vacuum” to nucleate from the primordial patch of spacetime. The amazing thing about the bubble, Guth saw, was that it would have contained a huge amount of antigravitational energy.

Although this idea may seem unbelievable, it’s actually in accord with standard particle theories. Here’s how it works:
Since an ordinary vacuum contains energy in the form of quantum fields, gravitational energy must be present as well. To understand why, it helps to remember Einstein’s famous equation, E = mc2. According to the equation, energy (“E”) and the mass of matter (“m”) are really two forms of the same stuff. So if matter, such as planet Earth, exerts a gravitational pull, so must energy. In other words, the energy-containing quantum fields of an ordinary vacuum exert a gravitational pull, albeit a weak one.

But when Guth used Einstein's relativity equations to see what happen inside a bubble of false vacuum, he found that the gravitational energy would have the opposite effect of ordinary gravity. In other words, this gravity would push, not pull — it would, in essence, be a powerful of antigravity.

Starting out as small as one billionth the size of a proton, the initial bubble of false vacuum would have doubled in size many times in an incomprehensibly short interval, propelled in this exponential growth by the antigravity. According to one inflation model, in just 10-35** seconds, the bubble would have grown to the size of a basketball. And some inflation models predict far larger growth than that, perhaps as large as 10(10)(12)* centimeters in diameter. That exponential number is a one followed by a trillion zeroes. (To print that many zeroes would require more than a million average size books.) Amazingly, if this picture of inflation is correct, it means that the portion of the universe we observe today is just an infinitesimally tiny mote compared to the whole.

The bubble of false vacuum would have had another peculiar property as well. According to particle theory, as the bubble expanded, the density of the energy within it actually would have remained constant. To picture this, imagine an inflating balloon. If the density of air inside is to be maintained, the total amount of air must be increased. Similarly, to maintain the same density of energy within the expanding bubble, the total energy must be increased — and by a huge amount, because the inflating bubble is growing exponentially. This theory seems to be saying that energy was created from nothing. And, in fact, Guth calls inflation the “ultimate free lunch.”

“It may sound as if I wasn’t there in my physics class when they talked about the conservation of energy,” Guth jokes. “But I was.” During inflation, he says, “the total energy of the system is conserved.” The enormous positive energy that builds up with ferocious speed during inflation creates a precisely balancing amount of negative gravitational energy (the ordinary attractive kind). “And so the net probably is zero,” Guth says.

Eventually (meaning in a very tiny fraction of a second), the false vacuum would have decayed, Guth realized. As this happened, the enormous energy that had been accumulating within the false vacuum would have been suddenly released, creating an exploding fireball of radiation and hot particles.

In other words, the big bang. “Inflation,” Guth concludes, “supplies the beginning to which the standard big bang theory is the continuation.”

* That is, ten to the power of ten, to the power of twelve.
** Ten to the power of -35.

Of course, then there is also the Star Trek: Voyager speculation.

Omega particle (Star Trek) - Wikipedia, the free encyclopedia

Based off Omega Minus Baryon, this particle is powerful enough that a couple of them could sustain an entire civilization. But they are tremendously unstable (being composed of 3 strange quarks) and dangerous.
During the very early days of the universe, all the matter was compressed by its own gravity. This makes an extremely hot and extremely dense singularity, the perfect conditions for strange matter[click] (can be found in neutron stars).
According to the theory (briefly described here), if a single omega particle had existed in that environment, and became unstable (easily done), it would have exploded, and been a perfect catalyst to offset the gravitational well effect and serve as the epicenter for the cosmic explosion that is the Big Bang.

Please note, however, that while Voyager is BASED on real science, it is not a canonised source.

Anyways, enjoy.