The Universe is a big place, and it is getting bigger. That is a little bit of a problem for us. For the last 13.8 billion years it has just been swelling. Some people think it will burst, others that we will just get very separated from the rest of the Universe. Therein lies a problem though. What is in the rest of the Universe?
Now we could probably make a guess, however it would be inaccurate. The reason is because we simply can only see a little bit. The problem is that the distance between our galaxy and other galaxies is constantly increasing, this has the bizarre side effect of causing the light from those galaxies to travel further. In fact the galaxies we can see are fairly close, and only a very small part of the Universe. We just cannot see the rest of the Universe because the light simply hasn’t had time.
What we can see is called the ‘Observable Universe.’ The Universe is much larger. In fact, imagine a coin the size of say, a pound coin, a euro or a dime. That is the size of the observable Universe. The total universe is larger than the whole earth by comparison, we are just not sure how much. Maybe the size of a sun instead, of the size of the observable Universe in comparison to the coin, we just didn’t know. So we set out to find this out.
The method used involved the measuring the curvature of space, we compared the light coming from a star with what we should have detected, and from whether it was brighter, dimmer or the same, we figured out the curvature of space between us and it.
Via the application of clever physics we came up with an estimate of the size of the Universe. Firstly we observed that the Universe may just be a massive sheet, allowing for the Universe to be infinitely larger than the Observable universe. Then by folding up the lowest limit we found into a sphere we found the lowest possible size for the rest of the Universe, 250 times what we can see.
The most accurate estimate of the size of the Universe is between 250 and infinite times the size of the Observable universe. The human mind cannot grasp such orders of magnitude, we are the flecks of dust of the tiniest motes of matter in the Universe. Do remember though, regardless of scale, humanity is important. We shall reach the stars, it is only a matter of time.