taken from: "science.howstuffworks.com"
Scientific American recently published a multi-page article about Big Bounce or Big Crunch Theory stating that Universal Big-Bang Theory would only be a part of the formation and deformation of the universe. In other words the Big Bang could have occurred several times, making the true age of our universe virtually incalculable. Read more at: http://www.scientificamerican.com/article.cfm?id=big-bang-or-big-bounce
While atoms are considered the smallest indivisible units concerning chemistry, spacetime works on a much smaller scale. The author describes these spacetime atoms as “the smallest indivisible units of distance…generally thought to be about 10-35m in size,” where as atoms are thought to be on the order of Angstroms of 10-10m. In other words, scientists would be dealing with particles 1025 or 10,000,000,000,000 trillion times smaller than that of an atom. The hope in dealing with such particles would be to describe the nature of a singularity, or a point of infinite density and temperature.
Currently the most accepted version of the beginning of time is that of the Big Bang. Meaning that at some point at time equal to zero all matter and energy converged at one infinitesimally small point of infinite density and infinite temperature – the Big Bang Singularity. The authors state that “at this point, our current theory of gravity – Einstein’s general theory of relativity – predicts that the universe had an infinite density and temperature.” The problem is that infinite values tend to contradict or break down general relativity itself. The authors combat this problem by describing what they call “a theory of quantum gravity, which would capture the fine structure of spacetime to which relativity is blind,” they call this theory “Loop Gravity.” Loop Gravity has an ability to describe the actually fluidity of spacetime. In other words the theory has the ability to describe the complicated interaction between matter and spacetime that we know as expansion and compression of space itself.
“Loop Gravity extends this insight into the quantum realm. It takes our familiar understanding of particles of matter and applies it to the atoms of space and time, providing a unified view of our most basic concepts. For instance, the quantum theory of electromagnetism describes a vacuum devoid of particles such as photons, and each increment of energy added to this vacuum generates a new particle. In the quantum theory of gravity, a vacuum is the absence of spacetime – an emptiness so thorough we can scarcely imagine it. Loop Gravity describes how each increment of energy added to this vacuum generates a new atom of spacetime.”
Meaning that space itself could be created (or expand) as each increment of energy was added outward. This would describe how space could continually expand much like a balloon expands as you blow it up (in all directions). But if such a theory were correct wouldn’t such particles be detectable on the outer regions of space or the background space radiation?
“The spacetime atoms form a dense, ever shifting mesh. Over large distances, their dynamism gives rise to the evolving universe of classical general relativity. Under ordinary conditions, we never notice the existence of these spacetime atoms; the mesh spacing is so tight that it looks like a continuum. But when spacetime is packed with energy, as it was at the Big Bang, the fine structure of spacetime becomes a factor, and the predictions of Loop Gravity diverge from those of general relativity.”
Thus, general relativity as we know it would exist and be capable of explaining modern or current events in spacetime. However at an infinitesimal point of infinite density and temperature (a singularity) these spacetime particles would interact with one another as gravity would change from an attractive force to a repulsive one. This is a confusing concept to master. It is obvious that as an object falls toward Earth it is being attracted because of the gravitational force of the large body (Earth). However when gravity pulls all matter inward to an infinitesimally small space a singularity forms and gravity switches from attraction to repulsion of spacetime particles, as described by Loop Gravity.
So what does this mean for the Big Bang? This means that as singularities form they begin to repel spacetime particles. What that means is the Big Bang could be more or less a cycle rather than a single event. We could think of the Big Bang as the moment when all singularities converged and repelled all pieces of spacetime particles apart in all directions creating a cataclysmic explosion of unknown proportions. This would cause the general expansion of the universe as we know it today. However as gravity continues to pull matter inward singularities within blackholes would begin to form over time (we have already seen these today). Generally speaking these blackholes would attract one another from far distances but as they converged they would form this infinitesimal singularity and the Big Bang process would happen all over again.
Thus our biggest concern is not really heat death or reaching an ultimate state of thermal equilibrium in the universe but rather when expansion will cease to exist as singularities begin to take control and compress space itself. Remember for this theory to be upheld much analysis would be needed to not only discover these small spacetime particles but also their interactions with ordinary matter. While current technology does not allow for the detection of such small particles, particles like neutrinos may be key to the detection of these spacetime atoms since they do not readily react with ordinary matter.
What really interested me in this article was not the overwhelmingly complicated physics but rather the idea that we may have absolutely no idea how old the universe is at all. Our current calculations would only explain the time since the last “big bang” and not the true age of the universe. How many times have we “bounced” and how many times will this process continue to cycle? These are the questions that spacetime particles can begin to answer in time.
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