This is the third book in the series that included 'The Theory of Nothing' the "The Universe Revealed.' My purpose in this new book is to more fully explain how science is actually done and how science fits into our culture along with religion and p...
I've talked about this before, but I think it needs some more thought because it demonstrates how insignificant we are in this huge monstrosity we call the observable universe.
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The observable universe is what its name suggests: it's the universe that can be seen by telescopes. It consists of all the matter that can be seen or detected by both Earth bound telescopes and space telescopes. As one would expect, the size and scale of the observable universe is subject to change.
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Just how large is the observable universe?
As you might know, the universe is roughly 13.8 billion years old and has been expanding at an ever-accelerating rate since then. At the present time, the radius of the observable universe is 45.7 billion light years. However, the observable universe is basically a ball, a sphere, with this radius and is the same in all directions. That's for an observer on Earth. So, we are at the center of this ball. However, an intelligent alien in a distant galaxy would see the same thing. He or she, if their species were bisexual, would assume that they were at the center of the universe. What this suggests is that the universe is much larger than we can observe.
Why is that?
The problem is that at the extent of our telescopic vision, the universe is expanding at near the speed of light, which means that anything beyond that point can't get back to us. A possibility exists that the universe is infinite in size, whatever that means.
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Currently, it is believed that the observable universe contains at least 2 trillion galaxies. I'm sure that number will go up when the James Webb telescope is launched. What's really so fascinating is that these galaxies are arranged in clusters that make up huge structures called filaments. These immense cluster structures contain hundreds of millions of galaxies. The Great Sloan Wall is an example of one of these immense structures. The wall is 1.38 billion light years in length and it contains many superclusters. The CfA2 Wall is another massive filament structure. The Hercules Corona Borealis Great Wall is 10 billion light years in size and is considered the current champion.
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These filaments are separated by voids, which contain little matter. This structured form is so interesting it has literally consumed astronomy's attention.
One of the things to keep in mind is that when we observe objects, mostly galaxies, at the far extent of our telescopic vision, we are seeing into the distant past, almost up to within a hundred million years after the Big Bang. It is very difficult to predict what the universe actually looks like at any given time. We can blame our lack of true vision on Einstein and his relativity theories. Light has a finite speed and the light from distant galaxies takes a long time to get here. What we're seeing is the baby pictures of the universe.
So, what to take away from this is that we don't have a clue about where we actually are in the actual universe. One of the sayings about the universe is that it has more stars than there are grains of sand on every beach on Earth. I would add that we are like one of those grains of sand.
