Most of us have got our heads around the fact that approximately 13.8 billion years ago our universe started with an almighty bang.
Even though we get the basic idea there are many questions that remain. These questions still puzzle scientists and astronomers to this day.
What was outside the big bang when it happened? What was before the big bang?
If the universe is expanding from a big bang, like we believe to be the case, what is at the edge?
That last one about the edge of the universe is one that got me thinking. I understand that there was a big bang and everything expanded out.
By my crude calculations, if the fastest anything can travel is at light speed, then the maximum distance that the universe has got to, from where it started from, must be at the most around 13.8 billion light years.
I have tried to draw what I mean here, excuse the crude diagram.
When I first started thinking about this, it seemed pretty straightforward, just a bit past the furthest star must be the edge of the universe.
My next thoughts were to find out what research and ideas were out there, by scientists, about this kind of theory.
As I started to read and learn about the edge of the universe, it became clear to me that I needed to stop thinking like a 3 dimensional human being.
Once you venture too far away from planet earth and delve into the depths of the cosmos things start to get very weird.
What is the furthest object we know about in our universe?
Thanks to Hubble, we have a picture of the furthest identified object in the universe – scientists believe this early galaxy is around 13.2 billion light years away, meaning we are witnessing something from the early formative times of the universe.
How close this far away galaxy is to any defined edge of the universe however, is not at all clear.
The “Observable Universe”
One of the problems with my simplistic edge of the universe theory is to do with what is called the “observable universe“.
If you asked me how big the universe could be I would have estimated that at the most around 28 billion light years across from one edge to the other.
However it is not that straightforward and in fact the observable part of the universe is estimated to be around 92 billion light years across.
No it doesn’t make immediate sense, however it is due to the expansion of the universe.
Expansion of the Universe
One thing that scientists will tell us is that the universe is expanding so rapidly that even if we tried we could never get to, or see the edge of it (assuming of course that there was an edge).
There is a lot of confusion around exactly how the universe is expanding.
Although many scientists and cosmologists will try to use the balloon analogy to describe the expanding nature of the universe, we find the “dough and raisins” analogy to be easier to understand.
Mano Sigham explains it well:
“The correct way to view the analogy is to think of the bread dough as being space and the raisins as the matter. As the bread bakes, the dough (i.e., space) expands carrying the raisins (i.e., matter) along with it. The hard thing for people to grasp is that there is no space outside of the dough. There is no oven for the dough to expand into. So the ‘explosion’ we speak of is not of matter expanding into space but of space itself expanding.”
So we can only see an as yet unknown part of the universe, and even if there was an edge, we would never be able to get there due to the rapid rate of expansion.
The universe is flat
We all know that humans used to believe the earth was flat.
If you walked too far, or sailed your ship too far past the horizon, whoops over the edge you would fall into a pit of scary monsters.
Another curve ball that disrupts my original view on the universe is that NASA scientists are pretty sure the universe is flat.
I had assumed, that the universe would have been a type of sphere due to the expansion of matter in all directions after the big bang.
It looks like I was wrong and to figure out why we need to journey back into space along with the WMAP probe.
If there is no edge, what is there?
This is where it gets really weird. We need to try to get our heads around the fact that the universe is flat, but has no edge.
So the answer to the question…
Does the universe have an edge? There is unfortunately no definitive answer but it does seem that no it does not.
What do you think? Do you agree that the universe is flat and stretches infinitely with no edge?
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