Could the age of the universe be older than we thought?

In summary, the size of the universe is a debated topic with various theories and interpretations. The observable universe, which is the furthest we can see, is estimated to be around 14 billion light years in radius. However, some cosmologists believe that the actual size of the universe could be much larger, potentially up to 43 billion light years. This is due to the expansion of the universe and the possibility of an inflationary period in its early stages. The actual size of the universe remains uncertain and is a subject of ongoing research.
  • #1
Rajendra_Vaidya
4
0
Recently I read that Universe is 156 Billion Light Years in size.
Even if every thing moves at speed of light, a 13 Billion years old universe
should not have radious more than 13 Billion years. Is it Correct?

Can the rate of expansion exceed speed of light?
 
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  • #2
156 Billion light years in size? Isn't "light year" a measure of distance only? How can that measure size, which is volume? Do you mean cubic light years?
Please clarify your question.
 
  • #3
I believe he means the radius of the universe. There is a common belief amongst cosmologists that the universe when first formed underwent a very rapid expansion period that far exceeded the speed of light. It is also known as the inflationary period and lasted approximately 10 to the power negative 12 seconds. http://instruct1.cit.cornell.edu/courses/astro101/lec31.htm [Broken]

The above link was about the best I found there is a little explanation as to what happened but doesn't really go into detail. I hope it helps you start to find what you are looking for.
 
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  • #4
The universe is BIG, mindbogglingly BIG!
(You may think it's a long way down to the chemist's, but that's NOTHING compared to space..)
 
  • #5
Kurdt, how do you know the universe is a sphere? Recent studies of the critical density in the universe have favored a flat one, not a sphere. I'm not saying that i am definately right or that you are wrong, just watch what you're saying.
 
  • #6
There are of course many theories as to the shape of the universe. A flat universe would imply one of essentially infinite size which would never collapse and never suffer heat death. My use of the word radius does imply a sherical shape, but in terms of imagining the expansion of a 3D object such as the universe a sphere is the logical tool to do so. I was not implying as the spherical model of the universe does that we live on the surface of a sphere.

You must remember that the sphere image is merely a tool to imagine a positively curved 3D universe in a 2 dimenional manner, whereas I was applying a sphere to represent a "boundary" to the universe.
 
  • #7
mind boggeling

do you mean the universe that has matter in it is 156 billion light years big or just in genral, because that would mean we would just hit into a barrier at some point, which makes no sense therefore the universe is infinite because space has nothing (well close to it which would diffuse forever into nothingness) in it therefor it can go on forever.

so the universe cannot have a size because it wouldn't just end


and also the space in which the universe lies cannot have an age because it is just nothingness and neither can the stuff in it because matter cannot be created or destroyed (this is insane isn't it)
 
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  • #8
Rajendra_Vaidya

Would you lke to quote the source where you found this information and maybe it would aid any further assistance rendered?
 
  • #9
arildno said:
The universe is BIG, mindbogglingly BIG!
(You may think it's a long way down to the chemist's, but that's NOTHING compared to space..)

arildno this sounds like D. Adams quoting HG to the G
bless his soul, he was a frood who knew where his towell was
 
  • #10
Kurdt said:
Rajendra_Vaidya

Would you lke to quote the source where you found this information and maybe it would aid any further assistance rendered?

we had an earlier thread at PF about that 156 billion LY
and I gave a link to the technical preprint

the study defined a "topological" size parameter which was supposed to work with a bunch of different geometries and the study was showing that the size parameter must be AT LEAST that amount

it could be 200 or 300 or 500 or infinite

I will see if I can find the old PF thread about this.

--------------
 
  • #11
i thought they gave the 156 ly value to the diameter of the "observable" universe
 
  • #12
The observable universe is only 14 billion ly in radius as the universe has only been in existence for that long and therefore light from any region beyond that has not had time to get here. The actual value varies as the Hubble constant is changed, but its between the limits of 12-15 billion ly anyway.
 
  • #13
That's wrong Kurdt, and would only be true if the universe had always been the same size. Of course, it has not always been the same size. The light that was emitted very early did not have very far to travel at all, you see. The "particle horizon," which is what you're talking about, is actually 43 billion light years in radius, IIRC.

- Warren
 
  • #14
Ok, well we have to allow for the expansion of the universe but we only observe the ojects as they were about 12-15 billion years ago so I guess its open to interpretation. In this case I guess it would be appropriate as the question is trying to put some bounds on how large the universeactually is at present. I apologise for my error.
 
  • #15
It's difficult to ask how large is the universe? because it's really open to interpretation. Cosmologists have to be very precise in the way they express sizes to avoid this sort of confusion. :smile: The universe appears to be 13.7 billion light years old, so we can only see objects that are less than 13.7 billion years old, as you said. Those objects might well be as much as 43 billion light years away, however, at the present time.

- Warren
 
  • #16
That is true. So it is very safe to say that the lower limit is 14 billion ly and anything after that is an open book. I think its important to note for clarities sake that galaxies very far away are all significantly red shifted. So they are traveling away from us at significant fractions of the speed of light. this is where the values of 40 odd billion ly come from. Then on top of that, if we believe in the inflationary period, there is something else beyond this value again. It would be nice to think that if we ever needed any extra mass and energy for the cosmological constant it could be found in the region we can't see.

All just wishful thinking maybe. :)
 
  • #17
I'll also note, Kurdt, that when cosmologists refer to 'the universe,' they usually mean the more qualified 'observable universe.' Ipso facto, whatever lies outside the observable universe cannot affect us in any way, not even gravitationally.

- Warren
 
  • #18
Hence the wishful thinking comment. I'll be sure to make my posts totally clear in the future in case anyone misinterprets. I was merely trying to establish where the value of 156 billion ly came from because I haven't read the original poster's source. I can't seem to find any reference to it.
 
  • #19
Kurdt said:
Hence the wishful thinking comment. I'll be sure to make my posts totally clear in the future in case anyone misinterprets. I was merely trying to establish where the value of 156 billion ly came from because I haven't read the original poster's source. I can't seem to find any reference to it.

here is a link to the original technical paper in arxiv
by Niel cornish]
and some other people
https://www.physicsforums.com/showthread.php?p=244969#post244969

there you will find an arxiv link to the paper and also to a BBC popularization article IIRC, and also a link to Niel Cornish website

his 24 gigaparsec is a "radius-like" figure so you double it to 58 gigaparsec to a "diameter-like" thing and convert parsecs to lightyears and get 156 billion LY. It didnt turn into 156 billion LY until he started talking to reporters and taking interviews

it is pretty abstruse, good luck trying to understand Niel's writing.
the main thing is it is a MINIMUM size figure----the U could be flat and infinite and that is kind of the simplest picture

but if it is finite then it has to be AT LEAST what Niel says, or we would notice it curving around----he and his buddies looked for signs of it curving around in the CMB and were able to rule it out for anything smaller than what he says
 
  • #20
We know so little about the universe I don't know how you could make a good guess. But I guess we have to start somewhere... I'd say the universe is 20+ billion years old.
 
  • #21
WMAP, among other experiments, has determined the universe is 13.7 billion years old. We don't have to guess.

- Warren
 
  • #22
chroot said:
WMAP, among other experiments, has determined the universe is 13.7 billion years old. We don't have to guess.

- Warren

Yeah Entropy, Warren is right
mainstream professional cosmologists are nearly all using the same
model of the universe
and these days they have arrived at a broad agreement on the observational data to plug into the model

the error bounds have been narrowed way down

so you take the model, which is two Friedmann equations, and you take the data (which since 1998 they are generally very confident in) and put the parameters into the model and it tells you lots of stuff: like the age is 13.7

Up until the mid 1990s the field was much more vague and there were people saying things like the universe is 20+ old, like you said just now.
But mainstream people don't say that any more because it doesn't make sense.

Of course it is your privilege to believe a very fringe thing like 20+
we can all believe what we want.
but since your taxes support the cosmology profession and they have
finally agreed on some basic things about the universe I would advise you to at least try to understand what they are saying and why they are so sure about 13.7

first understand the Friedmann equations, which are nice and simple, and then disbelieve if you are inclined towards nonconformism.
no one can blame you if you understand what you are rejecting
 
  • #23
Kurdt & other friends,

The source from which I got the info is space.com

http://www.space.com/scienceastronomy/mystery_monday_040524.html

As I understand our universe is like a bubble and our three dimensional space is the
surface and the thickness of the bubble.
From the illustration shown with the article, 156 BLight Yeras is the width or diameter of the universe.
 
  • #24
chroot said:
That's wrong Kurdt, and would only be true if the universe had always been the same size. Of course, it has not always been the same size. The light that was emitted very early did not have very far to travel at all, you see. The "particle horizon," which is what you're talking about, is actually 43 billion light years in radius, IIRC.

- Warren
Chroot,

You have just touched the very core of my question.

With your argument the question that arises is

If the universe was at a single point 13.7 BLY ago,
then how two points in the universe got separated by say 43 BLYs
in 13 BLYs?
 
  • #25
Rajendra_Vaidya said:
If the universe was at a single point 13.7 BLY ago,
then how two points in the universe got separated by say 43 BLYs
in 13 BLYs?
This is due to expansion of space.

First note that when talking about the radius of the observable universe a proper distance is meant. This is the distance between us and our particle horizon measured with a rod today (which is obviously unphysical according to special relativity).

Consider a radial photon beeing sent from our location at the time of big-bang. The location of the photon at each time is our particle horizon.

If it were no expansion of space, then the distance today between us and our particle horizon would be indeed 13.7 GLyr. But since space is expanding behind the particle horizon (between us and the photon) during this 13.7 Gyr, the proper distance between us and our particle horizon (after 13.7 Gyr) will be greater than 13.7 GLyr.

The actual distance depends on the cosmological model (in general it depends on Omega_matter, Omega_Lambda and the Hubble parameter).

Regards.
 
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  • #26
hellfire said:
This is due to expansion of space.

First note that when talking about the radius of the observable universe a proper distance is meant. This is the distance between us and our particle horizon measured with a rod today (which is obviously unphysical according to special relativity).

Consider a radial photon beeing sent from our location at the time of big-bang. The location of the photon at each time is our particle horizon.

If it were no expansion of space, then the distance today between us and our particle horizon would be indeed 13.7 GLyr. But since space is expanding behind the particle horizon (between us and the photon) during this 13.7 Gyr, the proper distance between us and our particle horizon (after 13.7 Gyr) will be greater than 13.7 GLyr.

The actual distance depends on the cosmological model (in general it depends on Omega_matter, Omega_Lambda and the Hubble parameter).

Regards.
If we were tracking 'This Radial Photon' would it not appeared
to have traveled faster than light?

i.e. More than 13.7BLYs distance in 13.7BLYs.
 
  • #27
Here, I believe it is important to note that Einstein's premise that nothing travels faster than light was not broken since the space ITSELF expanded and not matter traveling through it. We can use the inflating balloon analogy for this. Two points on the surface increase their distance from one another as the balloon expands, but neither point on the surface moves at all, it is the space expanding that moves them apart and therefore any matter embedded in spacetime does not violate this dictum.
 
  • #28
Rajendra_Vaidya said:
If we were tracking 'This Radial Photon' would it not appeared to have traveled faster than light?
Yes, the Hubble sphere (objects receding at the speed of light at a distance Rh = c/H) is located between us and our particle horizon and therefore objects located at the particle horizon recede superluminally.
 
  • #29
chroot said:
WMAP, among other experiments, has determined the universe is 13.7 billion years old. We don't have to guess.

- Warren

Then why are there stars >14 billion years old?
http://www.sciencemag.org/cgi/content/full/304/5675/1226b
 

1. What evidence supports the possibility of the age of the universe being older than we thought?

There are several pieces of evidence that suggest the age of the universe may be older than previously estimated. One is the observations of distant galaxies and their redshift, which indicate that the universe is expanding at an accelerating rate. This suggests that the universe must be older than previously thought in order for this expansion to have occurred. Another piece of evidence is the cosmic microwave background radiation, which is the leftover "glow" from the Big Bang. This radiation can be used to calculate the age of the universe, and recent measurements have suggested an older age than previously estimated.

2. How do scientists estimate the age of the universe?

Scientists use a variety of methods to estimate the age of the universe. One method is to study the expansion rate of the universe and use that to calculate how long it would have taken for the universe to reach its current size. Another method is to study the cosmic microwave background radiation and use it to measure the age of the universe. Additionally, scientists also use observations of the oldest known stars and galaxies to estimate the age of the universe.

3. Why do estimates of the age of the universe change over time?

Estimates of the age of the universe have changed over time as our understanding of the universe and its components has evolved. In the past, scientists may have had limited data or incomplete theories, leading to less accurate estimates. As new data is collected and new theories are developed, our understanding of the universe improves and allows for more accurate estimates of its age.

4. Could the age of the universe be younger than we thought?

While there is always a possibility for new discoveries and a change in our understanding, current evidence suggests that the age of the universe is most likely not younger than what is currently estimated. The observations of distant galaxies and the cosmic microwave background radiation both point to an older age, and there is no evidence to suggest a significantly younger universe.

5. How does the age of the universe impact our understanding of the universe?

The age of the universe is a crucial factor in our understanding of the universe and its evolution. It can help us determine the rate of expansion and how the universe has changed over time. Additionally, the age of the universe can also provide insights into the formation of galaxies, stars, and planets. A more accurate estimation of the age of the universe allows scientists to refine their theories and gain a better understanding of the universe as a whole.

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