The universe is 13.7 Billion years old. This is the maximum distance we can see?

Question

Since that would mean that the diameter must be 27.4 Billion light years in diameter, should we not be able to see objects farther than 13.7 light years away (unless we are in the very center, which from mathematical probabilty is VERY unlikely). So, what is the proper explanation for the absence of the record of longer distances being observed?

Answer 1

Very interesting question, and I'm not up to speed on all of it's implications, but I believe that we can't see to the very edge of the universe (aka "the volume of space that light has had time to reach us in") because of the condition the universe was in prior to an event called "photon decoupling."

According to the the "Big Bang" body of theory, up to about 300,000 years after the origin of the universe, the universe was an extremely hot, dense place - so hot, that radiation was bound up in matter.

But as the universe expanded, it cooled, and there came a point when the matter of the universe cooled enough that radiation - including light-bearing photons - broke away from matter. At this point, cosmologists say, the universe became transparent for the first time - because now it was open enough for light to go free.

Wow. "Let there be light!" Before then the universe was entirely dark. Knowing that still gives me a tingle of awe.

So, this is why we'll never be able to see to the edges of the universe - which as other Answerers have commented, would be the same thing as seeing far enough back in time to the "Big Bang" itself:

Beyond a certain observable limit (which I'm still researching but've not found) we would be seeing the universe, before light itself existed apart from it. There is no way we could see farther than that, because light didn't exist. Our telescopes would see that "edge" as getting fuzzier and fuzzier (and redder and redder, maybe?) until it fades into an utterly black void.

Another implication of your question is the relationship of the Universe's size to what we can see of it. Again I'm still on the lookout for how far we actually *have* been able to see in the cosmos... but something to keep in mind is a beast called "inflation theory" which postulates that the universe went through a period of enormous growth, far faster than light speed, in the first instants of its existance.

If that were true, the "observable" universe - this billion light year wide "bubble" that we can see - would be a *nothing* compared to the size of the whole universe.

Again, wow. What more could I say to that dizzying notion?

...

By the way, my understanding is that no "center" is necessary to understanding the universe. If we were two-dimension creatures on a balloon, and the balloon was blown up, we'd observe each of us getting farther away from each other, all around us. I'm given to understand that the universe itself is expanding in a higher dimension than we can see directly, so that's why nothing is expanding from a specific "point" in the universe. The whole thing is getting larger.

Answer 2

Limited technology is the explanation. They are now saying 15.7 light years because they have detected what they are calling remnant radiation that is 15.7 billion light years old because of its temperature. The number keeps getting bigger and bigger.

There is no explanation as to why we would chosen to be at the exact center of the universe. That would mean, of course, that the big bang happened right here on this very spot, which of course is even less probable than us being at the center of the universe.

Using light speed as a unit or measure also has its problems. They have observed that light is bent by stars and black holes. What is observably bending light is gravity. It would be logical to assume that anything with gravity bends light. A line with bends in it between two points is longer than a line with no bends. So, we have light 13.7 billion light years away passing billions maybe trillions of things before it gets here. We have no idea how far the thing generating the light is or even where it is. Since it's been moving for 13.7 billion light years at a changing speed, it's pretty safe to say that it's not where we thought it was.

Answer 3

Great question

Light can only travel at light speed...the fantastic supernova that flashed into existence in 1054 (witnessed by the Chinese astronomers) had occurred several thousand million years before...

To see something that is 13.7 billion years away...well, you do the math: besides what is on the very edges of the universe other than dark matter? Could there be a rim to the universe where matter exists, blatently no, or else it would be theoretically calculatable as having a mass and there would be a gravitiational impact that would be derivable in calculus (the presence of many of the object in space was predicted in calculus way before they were actually found)....

To get back to the question, The more powerful the telescopes we are throwing up now the further we can see into space and ergo the further back in time we can see: maybe the next telescope will provide us with this further insight but currently we are limited in our view of the universe

The universe as 13.7 billion years old is only a calculated age ultimately; it is based on a qualification of physicality based on a conceptual level without a strict emphasis on mathematical formalism. To me, not something that should indeed be pondered upon to heavily: it is as etheral as any theories of the nature of God himself; that has troubled philosophers and pissants alike for two thousand years...

Answer 4

Big Bang or not ... it's all crap !!
The figure of 13,7 b LY is uncertain, because some scientiest say it's older and some think it's younger. That depends very much on different facts (mainly value of expansion of the universe at certain times) we can't determine for sure.
However, let's take it as given, then the answer would be, yes, we can't look any further. But careful ... it is a look into one direction ... you can look as far on the other side, too !!
So you have to take the number of years of the age of the Universe as the biggest possible amount of lightyears in distance, we might "see" (not visibly, but with telescopes on invisible wavelenghts as like a radar or gamma or xray.

And ... by the way, we ARE the center ... the center of our visible Universe, because if we look into all directions, we can look into the same distance in all directions, therefore, we are the center of our v i s i b l e universe.

It is imaginable, that another species living on another planet in another galaxy let's say 5 b LY away, is bale to look further into the universe in a direction away from us ... however, as long as the age of the universe isn't really clarified, we just don't know that.
Therefore, when we talk about the universe, we should always keep in mind the "visible universe".

Answer 5

I am not sure if the 13.7 b figure is the right one but if it is, 13.7 b light years is the limit of the distance of the things that you can see. Think of it this way if you are receiving light from a star which is say 15b light years away, then that light must have originated 15 billion years ago when the universe and the star did not exist, which is quite a contradiction.

Answer 6

To be very honest, this is not a question that I can give you a definate answer to because recent advances in the field of astronomy and cosmology have returned conflicting information about the size of the observable universe and the rate of expansion.

Our theoretical limit as far as observing goes is about 300,000 years after the big bang...if we make a few assumptions.

Some have suggested that if the universe is expanding at an accelerating rate then some light reaching us will appear older than the actual age of the universe because the space it has to travers has actually expanded.

I think I would just treat this issue how archaeologists treat things that date past 33,000 years. Possible but iffy.

Answer 7

"should we not be able to see objects farther than 13.7 light years away (unless we are in the very center, which from mathematical probabilty is VERY unlikely)."



i may be a little confused but if we were in the exact center then 13.7 billion light years would be the max we see. any way outer than that wouldn't our maximum distance of sight increase?

Answer 8

You're forgetting that time is important here, in addition to distance. When you observe something one light year away, you are seeing it how it was one year ago because that is how long it takes the light to travel that distance. So if you look at something 13.7 billion light years away, you will in effect be looking at the Big Bang. To look 27 billion light years away is look before the Big Bang, which is undefined. So you can never view something that is farther away in light years than the age of the universe in years.

Answer 9

Hmm... maybe because the light from those stars has already gone? If we are not located in the center of the universe, that would mean, on one side we cannot see anything because it is too far for us to see... on the other side, the light has already faded away. With present technology we can on see a certain kelvin range. Until we find new ways to view farther, but lifespans of stars do not last long, heat only lasts so long before it reaches entrophy.

Answer 10

Probably because our technology isn't that up yet. I mean the space probes only got past pluto a couple of years ago. Maybe there is a ner technology that we don't know of, but with an naked eye, we cant see far.