Can anyone explain the apparent paradox in the size of the universe?

Question

These are the facts as I understand them:
The universe is around 14.5 billion years old
It began from a single point and has been expanding since
As the speed of light is a universal constant I assume the radius of the universe to be 14.5 billion light years
If I look through a telescope I can see further into space and further back into time and I can do this in all directions.
Say I had a really powerful telescope and looking at the furthest objects that I could see, ie 14.5 billion light years away, would I be looking at a universe with radius 14.5 billion light years or radius 0?
Both answers seem to be true at the same time and its keeping me awake at night.

Answer 1

The universe is a finite entity so it must have a maximum size.
It expands radially at the speed of light so the diameter would be about 30 billion light years.
If it has a maximum size the expansion will eventually have to stop.
The farthest galaxies visible do not exist to-day.
The Hubble red shift is interpreted as an accelerating expansion which can't be, so the interpretation must be in error.
I think the universe is somewhere around 6 billion light years in diameter,but it could be much older.{ Not bigger ]
If we could determine the actual size of the universe, both answers are true at the same time without being paradoxical.
Ya gotta get some sleep,regards.

Answer 2

The universe may be older than 14.5 billion are wider.

You are speaking about the VISIBLE universe and that got created LONG after the bang. Those 14.5 billion light year stars didn't form for quite a while and they move below light speed.

The BANG first put out Gamma Rays at the speed of light so it is possible the diameter of the universe is well over 50 billon light years and expanding all the time.

Those stars formed at a considerable radius from the center so when you see that light and it's 14.5 billoin light years away that star can ACTUALLY be 20 billion light years away as it has travelled from that point to anohter point (which you won't see for a long while.

Answer 3

Figuring out the size of the universe is not as simple as multiplying its age by the speed of light.

The current Inflationary Theory of the universe after the Big Bang proposes that in the tiny instant after the BB, before the four fundamental forces of the universe were separate and the "laws" of physics established, the universe could have expanded at an unthinkably high rate, slowing soon after, but creating a universe much larger in size than just expansion at lightspeed would have predicted.

There may be many vast regions of objects beyond the 14.5 BLY radius we can see, but the universe is not yet old enough for their light to have yet reached us.

As for radius zero, that doesn't make sense - just extend your arm in this universe, and you can see it's at least that wide.

Answer 4

When figuring radius, you also have to consider where the center of the Universe is. The Earth is not necessarily near that center of expansion therefore, from what point of expansion are you looking outward and, could you possibly be looking inward or through?

When dating stars and galaxies, scientists use a variety of data including electrographs, radiation signatures, light signatures, etc. It is a very complicated process that some still question.

Another way to look at your paradox idea though would be to think of a perfect sphere. In a sphere, 360 degrees in any direction is also 0 degrees even if the sphere is expanding at a constant rate (the universe is, according to Carl Sagan, expanding at an increasing rate).

Answer 5

Actually it is much larger than that. Wikipedia

http://en.wikipedia.org/wiki/Universe

adamently reports a diameter of 93 billion lightyears. The reason that the size seems to imply faster-than-light expansion is that the expansion is even more so an expansion of space than it is of matter and energy - now, can you imagine how empty space can "expand"? =8^?

And consider this (provided I have this right) - when we look at the edge of the semi-visible universe, we see objects about 14 GLY away that are receeding from us at close to the speed of light. So it seems to me that those objects should NOW be about 28 LY away, giving a minimum diameter to the universe of 56GLY. And the remaining 40GLY are due to the expansion of space?

.

Answer 6

Data suggest the universe is much older than 14.5 billion years. Just to bend facts to be congruent with the "big bang" theory, dark matter was hypothesized. The universe would have to be minimum 70(?) billion years old without dark matter. These are just numbers off the top of my head, but look into it if you want non high school indoctrinated scientific method.

Look into plasma theory and parallel universes. Our universe may just be one slice of bread in a loaf--example not mine.

Answer 7

First of all the belief you base the age of 15 billion years of the Universe existence is only calculated on the basis of Hubblel's constant.
The telescope cannot go beyond 1 par sec. It is only radio astronomy that can go beyound that.
The radius of the Universe was only a calculation based on Hubbles constant and galactic red shift.
15 billion years is a drop in the bucket relative to Eternity.
One calculation is as good as another.
Science has its own faith and beliefs.

Answer 8

This is something thats always fascinated me, and I've often thought about.

I've literally sat here and now thought about something else;
is there anything to say that we didn't explode into an already existing universe? The big bang theory is that a single entity exapanded into what we have now, but if scientists can actually recreate it - even if just for a very short space of time - is it not also possible that this happened elsewhere on a much larger scale and that "this" universe is actually one that's far far older than we can possibly guess?

This is pure speculation of course...

Answer 9

The Universe is a greatest wonder. The dimesions of the Universe are in infinity. When this is so how it be imagined by human beings as we all are finite in nature? Albert Einstein gave the famous Special Theory of Relativity saying it is four dimensional in nature including time in it. According to him it is looking like a rectangular box. But the fact is it is not possible to find out the length, breath and height of Space. This is the paradox.

Answer 10

You're assuming that time flows at the same rate throughout the Universe. It does not. Read 'Wrinkles in Time' by George Smoot ☺

Doug