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)?
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:
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.
- *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)
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.
Sources:
http://pdgusers.lbl.gov/~pslii/uabackup/big_bang/consequences/2500500.html
http://www.dailygalaxy.com/my_weblog/2011/04/a-real-flat-universe-beyond-comprehension-250-times-bigger-than-what-we-see-todays-most-popular.html
http://www.wisegeek.com/what-is-the-observable-universe.htm
http://www.exploratorium.edu/hubble/tools/center.html
http://www.atlasoftheuniverse.com/universe.html
For further reading:
http://en.wikipedia.org/wiki/Observable_universe
*Note* These numbers may vary source by source, but these estimates came from here:
http://www.dailygalaxy.com/my_weblog/2012/03/seven-trillion-dwarfs-and-billions-of-undetected-galaxies-in-the-observable-universe.html
http://pdgusers.lbl.gov/~pslii/uabackup/big_bang/consequences/2500500.html
http://www.dailygalaxy.com/my_weblog/2011/04/a-real-flat-universe-beyond-comprehension-250-times-bigger-than-what-we-see-todays-most-popular.html
http://www.wisegeek.com/what-is-the-observable-universe.htm
http://www.exploratorium.edu/hubble/tools/center.html
http://www.atlasoftheuniverse.com/universe.html
For further reading:
http://en.wikipedia.org/wiki/Observable_universe
*Note* These numbers may vary source by source, but these estimates came from here:
http://www.dailygalaxy.com/my_weblog/2012/03/seven-trillion-dwarfs-and-billions-of-undetected-galaxies-in-the-observable-universe.html
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