Many scientists have theorized against the acceleration of the universe’s expansion. Some pointed to the fact that the “surface brightnesses of the near and far galaxies are identical” (Sci-news 2014), or to the alternative that “the mass of everything is increasing” (The Daily Galaxy 2013).
A few days ago, I embarked on a thought experiment. At this time, dark energy is used to explain the acceleration of the universe’s expansion. However, nothing has been found YET. Maybe, dark energy a we know it does not exist. Maybe, energy as such does not exist at all. Or maybe, we’ve been looking at it from the wrong perspective. I began thinking that maybe dark energy is a fictitious concept used to compensate for our current lack of knowledge of the true course of the universe’s motion; like retrograde, maybe in a hundred years or so, the human race will look back at the time period when universal accelerating expansion was the accepted theory and smile an amused smile. I am not by any means claiming perfect knowledge of what we currently know about the universe, this is merely a thought experiment for the pleasure of thought and novelty.
Originally, I observed the model of the expanding balloon. Cool, I thought. It seemed to capture the concepts we covered in Earth and Space class pretty well: the spreading of the stars and the resulting dimming of their light. I tried to find a reason as to why the universe may be accelerating in its expansion via the expanding balloon model. Is it possible that the force that results in the universe’s expansion has always been constant, but that the fabric of the universe, as it stretches and thins, becomes increasingly elastic causing it to be expanding faster. Just as it is easier to blow a balloon once it is expanded, the universe could be easier expanded by the same force, resulting in acceleration. Maybe.
I then tried to reframe the problem. If we see that the universe is expanding from our perspective, what else could that mean relatively. Just as a hard right turn in a car would lead you to believe in a fictitious force pushing you to the left, what could the accelerating expansion mean if we observed the phenomenon from a different frame of reference? I tried to play around with the vectors on a little diagram I drew on a restaurant napkin:
Something like this...
This is what we see from Earth (blue one): that everything is moving away from our planet at increasing speed.
Rearranging the vectors,
This is what we get.
This diagram shows our current understanding, I believe, of the universe’s expansion. The diagram still, though, depicts that things are moving away from the Earth as objects that are further away moves faster than what is closer to us. Maybe we are on our way to a “Big Crunch” (The Physics of the Universe 2009) now.
Let’s rearrange the vectors one last time...
Now, although the motions of the universe are still the same from the perspective of Earth, it now seems as though the universe is not expanding outwards, but instead, on its way down. To where? I assume towards the largest mass in the universe which could have formed at the source of the big bang, at which time gravity may have been strong enough between the surrounding masses to coalesce back to the “center” as the distance between them would be the smallest in relativity to the other celestial bodies in the universe. However, the most interesting part about this model (although it is flawed, and I will explain why), is that there is no need for a mysterious energy to cause the expansion of the universe. All there is in this model is the force of gravity pulling everything back down, and that the bodies closer to the single most gigantic mass will feel a greater, faster, pull than the bodies beyond it. We will still perceive Hubble’s redshift and, seemingly, universal expansion, but by looking at it from a different frame of reference, we can take out the factor of dark energy.
Now... the flaw:
If we were to place a body of mass beside the Earth, everything falls apart.
Hubble observed that all bodies of mass are moving away from Earth. Here, we see that some celestial bodies will look as though it is moving towards Earth. So, could dark energy be the only way to solve this conundrum?
Maybe not.
Yes, this is not a proper visualization of the big bang theory, but let us imagine it for a second. If we injected an explosive into the center of an orange and detonated it, the remnants would be positioned kind of like this:
The red dot represents the source of explosion, where the center of the orange was. Because the force of explosion acts on the inside of the orange more than it does to the outer layer of the orange, most of the remnants will fall far from the center of explosion, leaving few pieces close to it. If this were a representation of the big bang, and the green dots represented celestial bodies, the force of gravity would cause the universe to look like this:
This model can explain why everything seems to be moving away from Earth. Maybe there are more than one of the theorized source of immense gravitational force, causing everything to be moving away from each other. Note that the scale of this illustration is way off in the fact that the Earth and everything around us should be much much much much much smaller in comparison to the rim of the universe, and much further from the edge than as depicted. Why can’t we, from Earth, then, see the rim? Two possibilities: one, because their gravitational force sucks light in instead of emits it, or, two, because it is too far away and light from things near them have not had time to reach us.
The flaw with this model is the difference in the rates of acceleration between things that are distant from Earth. From our perspective, things that are just, relatively, slightly further away move much faster than things closer to us even though the distance between them is, in the grand scheme, very small. If the source of gravitational force is so far away, that would mean that it would act on Earth and all its neighbours with about the same force, causing them to all move with the same speed and accelerate at the same rate.
Or maybe, what we perceive as being a huge difference in acceleration is actually not that big at all. After all, we have been looking at the vastness of our universe through our small eyes; observing an ocean of wonders through a single, relatively, infinitesimal pin hole.
Do we as a human race expect to get our understanding of the universe perfectly correct with the guesses we make when observing though this pin hole? No. But the joy of not knowing is much more powerful than any mass’ force of gravity. The wonder transcends all man made boundaries and brings society closer together in our collective attempt to understanding the mysterious and wonderful universe that we live in.
Bibliography:
The Physics of the Universe. "The Big Bang and the Big Crunch." The Physics of the Universe. N.p., 2009. Web. 15 Jan. 2015.
Sci-News. "Universe Is Not Expanding After All, Controversial Study Suggests." Breaking Science News SciNewscom. N.p., 2 May 2014. Web. 18 Jan. 2015. <http://www.sci-news.com/astronomy/ science-universe-not-expanding-01940.html>.
The Daily Galaxy. "’The Universe Is Not Expanding’ --A Radical Alternative to Big Bang Cosmology." The Daily Galaxy --Great Discoveries Channel: Sci, Space, Tech. N.p., 20 May 2014. Web. 18 Jan. 2015. <http://www.dailygalaxy.com/my_weblog/2014/05/the- universe- is-not-expanding-an-alternate-theory-to-big-bang- cosmology.html>.
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