Reason • Reality • Philosophy • Science • Psychology • Spirituality
The Eternal and Infinite Universe
It is common scientific knowledge that the universe is expanding, and that our observable universe was smaller in the past than it is now. This implies that at some point in the past, the universe would have been compressed into a very small, dense state. In order to go from that initial small, dense state to the immense and expanding universe we see today, the universe must have somehow “exploded” outward with unimaginable force. This explosion is known as the “big bang.”
This is a fairly simple version of the “big bang theory,” but it does capture its major features. One important addition to this theory is something known as “cosmic inflation.” Cosmologists realized that the universe is too “uniform” to have formed from this explosion alone. This “uniformity” refers to the fact that in any direction we look, the universe has a very uniform general distribution of matter and energy. In order to explain such uniformity, the idea of “cosmic inflation” was introduced. “Cosmic inflation” is period of astonishing accelerated expansion of the universe. Such a period of cosmic inflation, just after the moment of the “big bang,” would have essentially “stretched” the universe so much and so quickly that it “smoothed out” any irregularities in the early distribution of matter and energy in the universe, thus producing the very consistent distribution of matter and energy observed by astronomers today. Cosmic inflation is now a widely accepted part of the standard big bang theory.
After the period of cosmic inflation, the universe “settled down” to a more “normal” decelerating expansion. The reason that a decelerating expansion is considered normal is due to the force of gravitational attraction between all of the various parts of the universe. To understand this, imagine throwing a ball upwards with all your might. The moment it leaves your hand it begins to slow down, because there is no longer any force pushing it upwards, other than its own momentum, and this momentum will continue to decrease over time due to the attractive force between the ball and the Earth. Under normal circumstances the ball would soon fall back to Earth. If, however, the ball were projected upward with sufficient speed, (perhaps thrown by Superman, or shot from a powerful cannon with sufficient force) it would escape the Earth forever; it would still decelerate somewhat over time, however, due to the relentless but ever weakening force of gravitational attraction between the ball and the earth.
The expansion of the universe is very similar to motion of this ball. Once the initial big bang explosion happened, and after the period of cosmic inflation was over, there was nothing pushing the universe to expand outwards other than its own momentum. The force of gravity between all of the various parts of the universe, however, acts opposite the momentum of the expansion, and decreases the speed of the expansion over time. Cosmologists tried to determine whether the expansion was decelerating so quickly that it would eventually stop and reverse (like the ball returning to Earth), ultimately ending in a “big crunch” – sort of like the opposite of the big bang – or whether it was decelerating slow enough that it would continue to expand forever (like the ball thrown by Superman).
In 1998 that question was answered, but in a very surprising way: the expansion was not decelerating at
A number of candidates have been proposed to explain this “dark energy.” One of the most simple and elegant solutions involves a quantum process known as “virtual particle pair production.” While this is a quantum mechanical process, and while quantum mechanics can be quite complex, virtual particle pair production can be described in a way which is fairly simple to explain and understand.
Quantum uncertainty manifests itself in many ways. One of these involves the uncertainty regarding the precise amount of mass or energy contained in any volume of space. This manifests in the constant production of pairs of complementary “virtual” particles which exist for the briefest of moments and then mutually annihilate each other. This happens everywhere, all throughout space, all the time. We don't normally notice this constant production and annihilation of particles, because it happens so extraordinarily quickly and its effects are generally quite small. Nonetheless, the production and annihilation of these virtual particles does have real-world consequences. They produce an extremely small “pressure” which pushes space very slightly outwards. This pressure is typically unnoticeable but is cumulative with distance and becomes significant over cosmic scales. It is this outward pressure, due to virtual particle pair production and annihilation, which seems to be the source of the repulsive force of dark energy, i.e., the cosmological constant.
As the universe expands, galaxies move further and further apart. The attractive force of gravity between galaxies decreases as they get further apart. The repulsive force of dark energy, on the other hand, remains constant, and eventually overcomes the decreasing force of gravity. This causes the universe to begin to expand faster. At first the effect is very small, but the more that the universe expands and the force of gravity decreases, the more that the speed of the expansion increases. Eventually this expansion will become as fast as the expansion of the cosmic inflation of the big bang – this will essentially be a future period of cosmic inflation, analogous to the past period of cosmic inflation at the big bang. With nothing to counteract the repulsive force of dark energy, this second period of cosmic inflation will continue to accelerate out of control, eventually even tearing apart individual atoms themselves, in what has been very aptly called the “big rip.”
We now have a model of the universe which seems to have begun with a period of cosmic inflation, and also seems destined to end in another period of cosmic inflation. The beginning and the end of the universe thus look very similar in certain ways, but very different in others. The similarity is largely due to the fact that both periods are characterized by enormously accelerated expansion. The difference, however, is that while the beginning was characterized by an extremely high density of matter and energy, the ending will be characterized by extremely low density. This model, however, is not quite complete.
There are certain conditions under which virtual particles are not immediately annihilated, but instead continue to exist for a very extended period of time. When this happens, such particles are no longer considered to be “virtual” particles, but instead are considered to be “real” particles. Stephan Hawking, the noted theoretical physicist, described a process whereby particle pairs which are produced just outside the event horizon (the “edge”) of a black hole can be “pulled apart,” with one of the particles escaping out into space, and the other particle falling into the black hole. (The virtual particles which escape out into space from a black hole in this way, subsequently becoming real particles, are known as “Hawking radiation.”)
There is another condition under which virtual particles can be “converted” into real particles. This is
This modifies our view of the future period of cosmic inflation, because as the expansion of the universe gets faster, more and more virtual particles will continue to live on as real particles. Eventually, so many real particles will be created so quickly that their mutual gravitational attraction will be strong enough to cause the expansion to stop accelerating, and to actually decelerate – just as happened after the period of cosmic inflation at the beginning of the universe.
Now the past and future periods of cosmic inflation in our model of the universe look even more similar – so similar, in fact, that it seems that the big bang was not a unique one-time event, and that the life of the universe actually consists of an eternal cycle of “epochs.” Each of these epochs begins with a period of big-bang-like cosmic inflation which then “settles down” into essentially the type of universe we see today, until the expansion of the universe increases over time to initiate another period of big-bang-like cosmic inflation which then, in turn, serves as the beginning of the next epoch.
Thus the universe is eternal and infinite, and also always expanding on cosmological scales. This solves certain problems inherent in the big bang model, such as where the initial matter and energy required by the big bang model came from, and how it could ever have exploded at all (since such initial matter and energy would essentially have been a black hole with the mass of the entire universe). There simply was no “initial” matter and energy whose existence would need explaining: instead, matter and energy are “created” during each cycle of cosmic inflation. (It should be noted that this “creation” does not violate the law of conservation of mass-energy, because gravity acts as a sort of “negative energy” which balances the mass and energy of the particles which are created.) Furthermore, since there was no initial state of super-compressed matter and energy (with all the characteristics of an unimaginably massive black hole) there was never a time when it would have had to have inexplicably exploded.
It used to be the case that some sort of supernatural “Creator” was invoked to explain the “creation” of the universe from nothing. When asked where this “Creator” came from, the answer was simply that “the Creator always existed.” But now we can see that there actually never was a “creation:”instead of invoking some supernatural eternal being that “always existed,” we now know that it is the universe itself which always existed – with absolutely no need at all for any sort of supernatural intervention.
Thus, this model of the universe responds to the question, “Where did the universe come from?” with the very simple, straight-forward, and logical answer, “The universe always existed.” We live in an eternal universe.
Please help advance Scionics by commenting:
We welcome all comments, positive and negative, about our work and our website. We are particularly interested in any errors you find, whether these be simple typographical errors, or errors in facts or logic. If reporting an error, please be as specific as possible in identifying it, so that we will be able to properly identify and assess it. You may leave a publicly visible comment below, or in our forums, or you may send us a private comment using our contact page.