If There Is Much In The Window There Should Be More In The Room

Wednesday, March 6, 2013

The Visible Universe

The Visible Universe

The Universe within 14 billion Light Years

How big is our actual universe compared to the part we can see (including all the astronomical instruments)?

If you really want a headache (the good kind), take a long look at this "photo." No, this is not a photo of the cosmic microwave background radiation. (Which you can actually see for yourself if you change your television channel to one of the "fuzzy" stations) Nor is it a collection of graphs of a cell structure. So, instead of telling you what it isn't, how about I tell you what it is? This is, well... everything. Everything we can see and observe anyway. What you're looking at is the "observable" universe. This particular map has a cellular appearance due to how the galaxies tend to collect into vast sheets and super clusters of stars that are surrounded by stunningly large voids in between them. You and I and everything we've ever known are smack in the middle there, along with our Local group, which is a part of the larger Virgo Supercluster.

Since the speed of light is a constant in the vacuum of space, there is an outer edge to what is observable from Earth. That outer edge is defined by the objects within 14 billion years away (how old the universe is estimated to be), which is the time it would take for the light from these distant objects to reach us here on Earth. In this sense, the objects that are the farthest away from us are literally some of the earliest stars and galaxies in the young universe. it's quite likely that the stars we're observing are no longer burning and the ones that have formed from the gases expelled during the supernova of the previous stars are in another place entirely.

Since the universe has been expanding indefinitely since the big bang, the number of objects seen in the observable universe will shorten with time and it will appear as if the universe is much smaller than it does now - due to the light not having the proper amount of time to travel to the distant reaches of the universe. This expansion that's going on in all directions is also the reason why our solar system appears to lie in the middle of the universe. In fact, every inhabited planet circling a distant star will look out into the universe and they will see that the universe is expanding away from them, giving the impression that they are located smack in the center of it all.

Astronomers estimate that there are billions and billions of galaxies in the observable universe (as well as some seven trillion dwarf galaxies). Here's how astronomers breakout the visible universe within 14 billion light years.
The "observable" universe consists of:
- *10 million superclusters
- *25 billion galaxy groups
- *350 billion large galaxies
- *7 trillion dwarf galaxies
and *30 billion trillion (3X10^22) stars
(of which, almost 30 stars go supernova per second)

According to some math that I have no desire to go into, If you imagine the size of the observable universe (13.7 billion light-years) to be that of one nucleus of an atom and compare that with the size of the unobservable universe, then the total universe is 10 billion times larger than the size of the unobservable universe compared to a nucleus of an atom AND IT WILL CONTINUE TO GET BIGGER! (I know that was a mouthful, but read it a few times and it'll sink in)
You can look at those numbers here:

Keep in mind that it's impossible for us to know the exact size of the unobservable universe, so the above is estimation. It could be much larger than that.

About the Map
This map attempts to show the entire visible Universe. The galaxies in the universe tend to collect into vast sheets and superclusters of galaxies surrounding large voids giving the universe a cellular appearance. Because light in the universe only travels at a fixed speed, we see objects at the edge of the universe when it was very young up to 14 billion years ago.


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