Saturday, September 1, 2012

Relativity For Dummies and Discussing Universal Expansion

What is Relativity? Have you ever heard the word and not even really understood what it meant? It's actually extremely simple but probably the most poorly explained concept in astronomy. Watch this couple minute video to understand!
(The video above keeps disappearing. I'll keep trying to update this article!)
Through relativity, astronomers have come to believe that the universe is not only expanding, but that the expansion is accelerating exponentially. The universe is so massive, however, and since we cannot see even a tiny portion of it, many people disagree. Below is a little of both sides of the argument, and while both make sense and are probably equally correct, there are obviously so many facts that we have not gathered to be able to accurately say just what exactly is happening.
The picture shows just how tiny Earth is, and how we humans actually beleived at one point that we were the center of the universe. Such wonderful arrogance!
On the top left is Earth, to its right is our Solar System, and again to the right are several solar systems and star clusters near us, and to the right some more show the entire Milky Way, which contains billions of stars all millions and millions of miles apart from each other for 100,000 light years. The Local Galactic Groups show several entire galaxies much like our Milky Way, where we live, which when zoomed out shows us that our 100,000 light year galaxy is a just a speck. The Virgo Supercluster is a colossal collection of star systems and over a hundred entire galaxies spaced over 110 million light years. Yes, this means that at light speed (671 million mph) it'd take 110 million years to leave the Virgo Supercluster, where the Milky Way is one of over 100 speck sized galaxies. The Local Superclusters picture shows hundreds of Virgo Supercluster sized clusters. Yes, so it'd take billions of years to traverse that distance at light speed. And finally, the Observable Universe is the coyly named collection of 46 billion light years' worth of superclusters, galaxies, star systems like our own, and so on.
The name is "Observable Universe" is very deceiving because for a couple complex reasons. First is that the universe itself is widely agreed to be only 13.7 billion years old. This means that light at the beginning of the universe from the Big Bang would have only just reached us recently, in 2009 in fact, which looks like a black impenetrable border. Everything beyond this border is blackness to us. For all we know, this is the edge of the universe, and there could very well be nothing beyond it.
Age of the Universe was estimated to be 13.7 billion years because of light's maximum speed being the maximum speed of the universe, thought by some to make the radius of the observable universe amount to only 13.7 billion light-years (light speed×age=size), which is only a single speculated age of the universe based on light. Logical deductions like this makes sense only in a flat, static Minkowski space-time based universe of special relativity. The real space-time of the universe, however, is clearly curved in a way that corresponds to the rate of expansion of the universe (based on Hubble's law.) Therefore, the multiplication of the age of the universe by the speed of light should not actually be correct if the universe is indeed curved and not flat, (Ned Wright, "Why the Light Travel Time Distance should not be used in Press Releases"). The observable universe is a sphere with a 46 billion light year radius derived from where the expansion of space has co-moved all stellar objects outward (away from each other and our Milky Way galaxy.)
Irony: It is ironic, however, that the farthest "observed" stellar phenomenon UDFj-39546284 was 13 billion light years away, however if Hubble's law holds true, then the actual distance is 30 billion light years distance now even though the light took 13 billion years to reach us. The expansion of the universe has already caused this phenomenon to be pulled far away from where we actually observe it to be. This is why astronomy stands in deep scrutiny, how can anyone prove either of these perspectives? The line between fact, belief, and theory are muddled. Our current technology is limited and therefore demands a level of intuition. Furthermore, our own spatial perceptions deny us the ability to fully see what is happening to the light during its long voyage to Earth, which is what Hubble's law and Minkowski's space-time attempt to sort out.
Located below shows some of my own disbelief while at the same time demonstrates my own level of comprehension, which right now is down the middle. I can see both sides of the coin, but the facts at hand clearly show that we are still missing so many of the puzzle pieces.
469 ly is the approximate total spheroidal distance of observable universe (our neighborhood)
939 ly speculative maximum size of universe
-And yet astronomers also say-
4×1069J estimated total mass-energy of the observable universe, (e=mc2 or Energy=mass×lightspeed2)
8×1069J total universal energy output
These numbers are far too small, a single supernova has up to 2×1044J of energy output and a neutron star puts out 5.23×1046J each second. Our Sun, which is only a little larger and hotter than the average star, has an energy output of 3.8×1026J each second, and yet there are an estimated 5009 galaxies which could each contain sextillions of stars. The total output of the universe might not be based on total energy output of all objects within, but shouldn't it be? Hypothetically speaking, if a container was filled with electricity, would not that container also have an energy output equal to or greater than its very contents?
Size of the Universe and Its Expansion: Inferring the overall size of the universe is impossible since the universe is still expanding, which simply means that the distant objects we observe have already moved considerable distances from where we observe them to be. They have actually traveled vast distances further away from us due to the vast amounts of time their light takes to reach us, which is multiplied exponentially by the speed that they move away from us as well. Furthermore, since the universe itself is not bound by maximum speed laws (light speed), the expansion of the universe itself can exceed light speed, perhaps even far exceeding it, without ever violating the laws of relativity.
This fact coupled with stellar objects already moving at gargantuan speeds (millions of miles per hour) means that the objects themselves are being pulled along with the edge of the universe as it expands, and the expansion is accelerating exponentially. From an astronomer's perspective, this makes their velocities seem greater than light speed, which is not so. These stellar objects travel distances far exceeding the distances traveled by light in year, but without ever actually matching or exceeding light speed. This is the problem astronomers encounter when measuring the speeds of moving objects in a moving universe. Where speed is the rate of distance traveled, if that distance is forever increasing then no accurate speed can be measured based on the movement of objects relative to such unspecified reference points (e.g.: to measure the distance between one object and another object at an unspecified distance=silly!). Astronomers would need to calculate the total speed the edge of the universe is moving away from us (reference) in order to measure the rate of expansion, hence, to calculate the actual size of the universe. This stretching of the overall distance of the universe around us should cause the speed of moving objects to seems less, but in this case the stellar objects are being indirectly pulled with the speed of the expanding universe, which has no discernible maximum speed. Therefore, their increasing distances from us actually make them appear to go faster than the speed of light, rather than slower. They are exceeding light speed since they are traveling larger distances at a greater rate, yet they aren't going that fast at all since the overall distance is being cut down due to these distances being shortened during this "pull" of the expanding universe.

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