"Paradox": Light Years vs. Age of Universe

[EWright]

Here's some 'food for thought.' This is actually explainable, but I thought it'd be fun to put it towards you good folks to see how you view this:

 

NASA and popular publications tell us the age of the universe is 13.7 billion years to within .1 billion years. This is based on the 'age' of the furthest light we are able to measure in the universe.

 

So was the most distant light that we can measure, which is referred to as being 13.7 billioon light years away, actually given off 13.7 billion years ago? And was it 13.7 billion years away AT THAT TIME or is it that distance away from us NOW?

 

If the light is 13.7 billion years old, the universe would have been less than a billion light years in radius at the time it was given off, so it should have reached us long before now. Conversely, if the light was emitted from it sorce 13.7 billion years ago and is now reaching us after traveling that distance, that would mean the universe had such a radius at that time even though it wasn't old enough to have become that large yet. So which perception of when this light was given off is the correct one?

 

(I avoided acknowledging the most obvious answer because I assume it is the one most of you will allude to. However, my corrections for SR explain it without basing it on the premiss I assume you will draw on.)

[Tormod]

Holy smoke. How many times per week will this question pop up?

 

Post your own insight before playing silly games.

[infamous]

Here's some 'food for thought.' This is actually explainable, but I thought it'd be fun to put it towards you good folks to see how you view this:

 

NASA and popular publications tell us the age of the universe is 13.7 billion years to within .1 billion years. This is based on the 'age' of the furthest light we are able to measure in the universe.

 

 

 

(I avoided acknowledging the most obvious answer because I assume it is the one most of you will allude to. However, my corrections for SR explain it without basing it on the premiss I assume you will draw on.)

 

Because the speed of light is invariant, we can conclude that our observation of these events are approx. 13.7 billion years old. However, because of expansion, the universe may not be the size we often assume. Depends upon the varing rate of this expansion over time, and these facts are difficult if not impossible to interpert.

[Tormod]

NASA and popular publications tell us the age of the universe is 13.7 billion years to within .1 billion years. This is based on the 'age' of the furthest light we are able to measure in the universe.

 

If you had read the information from NASA about the WMAP results you'd know two things:

 

1) The measured age is not done by observing distant light but by measuring the overall temperature of the CMB

2) The CMB dates back to 379,000 years after the Big Bang, which was the point in time when it was cool enough for atoms to form.

 

It would also help to be aware that this is *observational* data gathered through many years. It is not empirical. It supports the Big Bang theory and also the theory of inflation.

 

Everything we know about the universe may be wrong. Yet the WMAP data is what explains the theories best at the moment. It is as simple as that, really.

[EWright]

If you had read the information from NASA about the WMAP results you'd know two things:

 

1) The measured age is not does by observing distant light but by measuring the overall temperature of the CMB

2) The CMB dates back to 379,000 years after the Big Bang, which was the point in time when it was cool enough for atoms to form.

 

It would also help to be aware that this is *observational* data gathered through many years. It is not empirical. It supports the Big Bang theory and also the theory of inflation.

 

Everything we know about the universe may be wrong. Yet the WMAP data is what explains the theories best at the moment. It is as simple as that, really.

 

I do thank you for clarifying the difference in the age measurement as it relates to the CMBR. There is a lot of material out there, and I'm sure you are more versed in it than I am. However the question can still be posed in regards to visible light near this distance.

 

I can also explain the reason that they CMB measures as such without the need for the big bang. I mention this because I know this measurement is one of the staples of bb theory and must be addressed by any alternate theory. I also believe mine can answer many of the unanswered questions that trouble bb theorists.

[Tormod]

I can also explain the reason that they CMB measures as such without the need for the big bang.

Huh?

 

The CMB measurements were done long after the Big Bang theory saw the light of day, and as such is not a staple of BB theory but a proof for it.

[EWright]

 

The CMB measurements were done long after the Big Bang theory saw the light of day, and as such is not a staple of BB theory but a proof for it.

 

This is what I meant as well. Because it is considered proof of the big bang, I understand that any alternate theory must account for another reason for the CBM. Mine does.

[bumab]

Holy smoke. How many times per week will this question pop up?

 

Gosh, no kidding.

 

There should be a mandatory reading on the subject...

[Tormod]

Gosh, no kidding.

 

There should be a mandatory reading on the subject...

 

Good idea. An "Age of the universe FAQ". ;)

[EWright]

Gosh, perhaps I should apologize for being new to your site.

[EWright]

By the way, it is NOT an age of the universe question. I am asking what the position of the SOURCE of light that we measure as 13 billion years old was at the time it was given off, relative to the position at which we are receiving it. Can we address the question at hand please?

[Tormod]

Gosh, perhaps I should apologize for being new to your site.

 

You could have bothered to search the site first (which our rules ask you to). Or even have a look at the astronomy category, where this topic is being discussed in at least 5 other threads:

 

http://hypography.com/forums/forumdisplay.php?f=9

[infamous]

Gosh, perhaps I should apologize for being new to your site.

 

No need to do that EWright, just keep a stiff upper lip. Just remember the truth will stand when nothing will and the truth is what we all are searching for here at Hypography. Have a good one and welcome to Hypography.

[Tormod]

By the way, it is NOT an age of the universe question. I am asking what the position of the SOURCE of light that we measure as 13 billion years old was at the time it was given off, relative to the position at which we are receiving it. Can we address the question at hand please?

 

Like I wrote, the CMB dates from the time when atoms where formed. This was the first time radiation was able to permeate the universe. Thus the universe itself is the source.

 

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

 

The position was the entire universe.

[Tormod]

And the position of other objects at 13 billion years - within our observable universe.

[EWright]

Like I wrote, the CMB dates from the time when atoms where formed. This was the first time radiation was able to permeate the universe. Thus the universe itself is the source.

 

http://en.wikipedia.org/wiki/Cosmic...round_radiation

 

The position was the entire universe.

 

I asked that we refer to visible light and not the CMBR. Let us then move our timeling to only include light given off 13 billion light years ago, rather than the CMBR which is at 13.79 billion light years please.

 

And no, the entire universe was not the source of light we see from a specific star or galaxy near this distance from us.

[EWright]

And the position of other objects at 13 billion years - within our observable universe.

 

Do you not see the contradiction in this statement as applied to the CMB? If you're refering to a time after the CMB, then um, yes, if there are other objects at that distance that do not emit light and you're able to observe them from earth, sure? ;)