Caris McKee-Shell
Explaining what we know about the edge of the universe and how this can change.
We imagine the universe, the place that holds our solar system and many others beyond our sight, to be vast and empty and full of stars. We see planets and comets and the Earth at a distance. Although humans have existed for between five and seven million years, space is still a place that requires much questioning and uncertainty. Surely, it cannot be infinite, because everything must end. But if the universe is, in fact, finite, then where is the edge of the universe, and what is there? What is beyond this? You may imagine a black curtain, or a plain brick wall, though plausibly we know this cannot be the case. So what does it look like, and how do scientists know this if it has never been reached?
The estimated diameter of the observable universe is around 93 billion light years, although of course there remains to be significant doubt about this. To date, the farthest distance travelled by a man-made object was by Voyager 1, travelling a total of somewhere near 13 billion miles, or 0.0022114013353023 light years. This demonstrates how far we have developed, but also how much more we have to achieve before even making it close to where it is expected that ‘the edge’ is found.
So, putting all physical boundaries aside, and imagining that in a hypothetical situation, it was possible to travel to the edge of the universe, what would happen? The answer to this is explained by Einstein's theory of relativity. This, put simply, is the idea that gravity is not an invisible force but instead is the curvature and distortion of space around an object. The bigger the object, the more it impacts the space around it. Therefore, the universe is considered to be spherical and bends, in a way that allows it to be finite yet still boundless.
The analogy used by Bill Bryson in ‘A Short History of Nearly Everything’, and by many other scientists trying to explain this phenomenon, takes into account our own Earth. We know now that the Earth is spherical, curving and bending in similar ways to the universe. Imagine that a person from a flat planet, that has never seen a sphere, is brought to our Earth and instructed to find the edge. If they began in one spot and, theoretically, travelled in a straight line, they would eventually end up back in the same spot they first found them-self. This is the same idea that applies to the universe. If you travelled outwards in a straight line, eventually, you would find yourself back in the same spot. Finite, yet boundless.
Science isn’t constant or correct. Of course, there is not yet a way to find out what would happen if we did travel in a straight line into space, as we have not developed the equipment or technology to have this ability, and it is highly unlikely that we ever will. If we ever do travel this far, and make our way to the edge, maybe we will find something new, something no one predicted, or maybe scientists will end up in the same place they began, thereby proving the theory of relativity. Science, in a sense, is guesswork, based on as much fact as that can be defined as fact, collecting more and more information until finally there is enough to form a theory. Advances and changes are happening all the time and maybe, one day, Einstein’s theory will be proven. Until then, and until more evidence that supports or contradicts this theory, it is the most fathomable and considerably possible explanation. There is no ‘edge’ to the universe.
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