is the Universe 45 billion yrs old ?

north · #1 (**permalink**) 06-October-2008, 02:40 AM

I know its bizzare but some think so

just asking

I've never heard of this before myself !!

RussT · #2 (**permalink**) 06-October-2008, 02:42 AM

Quote:

Originally Posted by north

I know its bizzare but some think so

just asking

Geeeeeeez North...

Who are 'some'? and why didn't you add a link to identify them, and why they think this?

And, why didn't you ask this in ATM, as the only 'answer' you can get in Q&A is NO~

north · #3 (**permalink**) 06-October-2008, 02:49 AM

Quote:

Originally Posted by RussT

Geeeeeeez North...

Who are 'some'? and why didn't you add a link to identify them, and why they think this?

Russ T

when read that , I thought give me a break

so here's the site

http://www.scienceforums.net/forum/

then go Astronomy and Cosmology

if its still hard to find let me know

north

north · #4 (**permalink**) 06-October-2008, 03:00 AM

Russ T

is this not rather bizzare ?

quite frankly , I don't believe it

novaderrik · #5 (**permalink**) 06-October-2008, 03:04 AM

i think i've read that the universe can be about 45 billion light years across, but is only between 13 and 14 billion years old.
i remember something about the rate of acceleration being faster immediately after the big bang than it is now or something like that.

north · #6 (**permalink**) 06-October-2008, 03:08 AM

Quote:

Originally Posted by novaderrik

i think i've read that the universe can be about 45 billion light years across, but is only between 13 and 14 billion years old.
i remember something about the rate of acceleration being faster immediately after the big bang than it is now or something like that.

explain

thorkil2 · #7 (**permalink**) 06-October-2008, 03:58 AM

45B lys across is incorrect. The Universe is 13 to 14 B years old, so the visible horizon in any one direction is 13 to 14 B yrs. If the age is correct, then the maximum distance from visible horizon to visible horizon is 26 to 28 B lys.

thorkil2 · #8 (**permalink**) 06-October-2008, 04:06 AM

OK, I see what they are saying. I don't quite see how the number 45 falls out of all this, but he is saying that the light you see left the object nearly 14B years ago, during which time the object has continued to recede. Obviously it isn't where you see it any more. So I should clarify my statement to put stronger emphasis on "visible."

Van Rijn · #9 (**permalink**) 06-October-2008, 04:53 AM

Quoting a relevant post from another thread:

Quote:

Originally Posted by speedfreek

Hi there! There are many ways of measuring distance in an expanding universe - here are the most useful ones for this question

Light Travel Time.
The time that light has taken to make the journey from the source of emission to our detectors.

Co-moving Distance.
The distance we think the source will have receded to during the time that the light was travelling, due to the expansion of the universe.

The oldest light we have detected are the photons that were emitted with the Cosmic Microwave Background Radiation. These photons filled the universe at the time and the ones we have recently detected are estimated to have been travelling for around 13.7 billion years. This is where the 13.7 billion light-year radius for the observable universe comes from, as the photons are coming in from all directions.

But we think that the coordinate that those photons were emitted at has since receded to around 46 billion light-years away. So, our observable universe has a co-moving radius (i.e. how big it is right now) of 46 billion light-years.

You mention another distance of 142 billion light-years, and I think that might be a reference to the misreported lower size set for the whole universe (not just our part of it), but that is another subject all in itself (The figure was actually 78 billion, but some sources assumed it was a radius and doubled it when they shouldn't have!). But having seen Jeff's post, it might be the 42 million light-year original distance that the CMBR we currently detect was emitted at.

And a link to a short thread that might be helpful:

Does relativity factor in the age of the universe?

north · #10 (**permalink**) 06-October-2008, 05:14 AM

Quote:

Originally Posted by Van Rijn

Quoting a relevant post from another thread:

And a link to a short thread that might be helpful:

Does relativity factor in the age of the universe?

well isn't that new !!

for most of us

why is this not more publicly known ?

Ken G · #11 (**permalink**) 06-October-2008, 10:30 AM

It's not more publicly known because the media insists on reporting ages as if they were distances. In fact there are several different ways to measure distance in cosmology, and the light travel time is the least sensible one.

sabianq · #12 (**permalink**) 06-October-2008, 06:37 PM

is this where it comes from?

http://www.cea.fr/var/cea/storage/st...elbaz_54gb.pdf

Quote:

The current standard cosmological model
involved a radius of the observable Universe of some 45 billion light-years, with an age of around 13.7 billion years

or here?
http://map.gsfc.nasa.gov/site/glossary.html

Quote:

Horizon
The limiting distance from which we can have received information since the Big Bang, 13.7 billion years ago, due to the finite speed of light. Since the universe has been expanding throughout its history, the "proper" distance to our horizon today is close to 45 billion light-years. This bounds our observable universe.

and here
http://huterer8.physics.lsa.umich.ed...MB_Huterer.pdf

Quote:

At this distance from
the display, you can see patterns that extend 45 billion light-years, all the way out to the edge of the observable universe.

how about this?

and here:
http://background.uchicago.edu/~whu/Papers/HuWhi04.pdf

Quote:

Likewise, researchers can determine the distance CMB photons have traveled before reaching Earth—about 45 billion light-years. (Although the photons have traveled for only about 14 billion years, the expansion of the universe has elongated their route.)

how about this:
http://arxiv.org/PS_cache/astro-ph/p.../9905393v1.pdf

Quote:

However the distance to its starting point would be roughly 45 billion light years, the current size of the horizon.

here an interesting one:
http://geology.wcupa.edu/mgagne/ess3...verse-map.html

Quote:

Accordingly, those Big Bang embers are now some 45 billion years out.

and

http://www.fuw.edu.pl/~bohdang/wykla...ogy/notes1.pdf

Quote:

The current Universe is
13.7 billion years old and has an observable size of 45 billion light years.

then there are other measurements:

Universe Measured: We're 156 Billion Light-years Wide!

http://www.space.com/scienceastronom...ay_040524.html

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

Quote:

Astronomical observations indicate that the universe is 13.73 ± 0.12 billion years old[1] and at least 93 billion light years across

hey RussT, sounds like to me that a lot of research suggests that this 45 billion lightyear size is not ATM, rather very Mainstream. It is understandable to misinterpret what is being said as the universe is 45 billion years old rather 45 billion light years in size.

(because the universe has been expanding since the beginning of time it has to be bigger than it is old.)

speedfreek · #13 (**permalink**) 06-October-2008, 06:55 PM

Quote:

Originally Posted by sabianq

then there are other measurements:

Universe Measured: We're 156 Billion Light-years Wide!

http://www.space.com/scienceastronom...ay_040524.html

That was a widely misreported figure, based on misconceptions surrounding the paper Extending the WMAP Bound on the Size of the Universe.

We think the observable universe has a radius of 46 billion light years and thus a diameter of 92 billion light-years. But the question arose as to whether the overall topology of the universe might "wrap around", meaning that if the whole universe were small enough and light had been able to circumnavigate it, we might be looking at the same regions of space when we look in opposite directions!

If that were the case, our diameter of 92 billion light-years might contain repeated regions of space, and the whole universe might actually be smaller than we think! So a group of scientists analysed the CMBR data for any indication of repeating patterns in different areas (a "matching circle" analysis) and found none.

They were able to say with confidence that at least 78 billion of our 92 billion light-years diameter observable universe was comprised of unique space, so the whole universe must have a diameter of at least 78 billion light-years.

Unfortunately, early in the media reporting of these results, someone inferred that the 78 billion light-years figure represented a radius, and doubled it to a 156 billion light-year diameter erroneously.

See here for more information.

John Mendenhall · #14 (**permalink**) 07-October-2008, 04:09 PM

North, there's a lot of slop about how the age and size of the universe are reported in the popular press. Briefly, 13.7 billion years is a good value for the age, and since the universe has been expanding all that time, the current size is about 45 billion light years. Some parts of the universe are unobservable; due to the expansion they are moving away from us at a value that red shifts all their output into nothing.

If you look at it as above, you have reasonable values without getting into heated discussions about 'edges' and 'FTL expansion' and 'bound systems'. Let the big boys duke it out over that stuff; if you read enough BAUT you'll notice that they don't all agree. That's what mainstream science is about; the best ideas pass the tests, but they're continually challenged.

JustAFriend · #15 (**permalink**) 08-October-2008, 02:39 PM

45?

I thought Hitchhiker's Deep Thought came back with the answer of > 42 < ???

Maybe it was a rounding error.....

;-)

geonuc · #16 (**permalink**) 09-October-2008, 10:27 AM

Quote:

Originally Posted by sabianq

hey RussT, sounds like to me that a lot of research suggests that this 45 billion lightyear size is not ATM, rather very Mainstream. It is understandable to misinterpret what is being said as the universe is 45 billion years old rather 45 billion light years in size.

RussT suggested that an age of 45 BY is ATM, not a size of 45 BLY.

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