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#39153 - 07/24/11 02:17 PM Re: Light From Distant Galaxies. [Re: redewenur]
Bill S. Offline
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It will be interesting to see if anyone else comes in with a yes or no.

2) Is there a real difference between infinity and eternity?

My initial thought was "yes", but I have moved a long way towards "no".
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#39157 - 07/24/11 05:57 PM Re: Light From Distant Galaxies. [Re: Bill S.]
Bill Offline
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Quick answer: Infinity applies to anything that has no limit. Eternity applies to unlimited duration, something like your wait in the dentists office. So eternity is a specific form of infinity.

Bill Gill
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#39158 - 07/24/11 06:39 PM Re: Light From Distant Galaxies. [Re: Bill]
redewenur Offline
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re (2) see Bill Gill's post above.
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#39159 - 07/24/11 08:51 PM Re: Light From Distant Galaxies. [Re: redewenur]
Bill S. Offline
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OK, but your wait in the dentist's is longer if you have toothache, so that must be a Cantor-type infinity. smile

Seriously, though, it sounds as though you are saying that eternity is "infinite time", and infinity is "infinite everything else". Would that be right?


Edited by Bill S. (07/24/11 08:52 PM)
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#39160 - 07/24/11 10:32 PM Re: Light From Distant Galaxies. [Re: Bill S.]
redewenur Offline
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There's another word, 'sempiternity', that's sometimes used where a particular distinction is called for, as explained in Wiki:

"While in the popular mind, eternity often simply means existence for a limitless amount of time, many have used it to refer to a timeless existence altogether outside time. By contrast, infinite temporal existence is then called sempiternity. Something eternal exists outside time; by contrast, something sempiternal exists throughout an infinite time. Sempiternity is also known as everlastingness."

For our purposes, I'm happy to stick to the popular usage of the word 'eternity'. So, yes, eternity is the label I use for infinite time, i.e. time without beginning and without end. If, for any reason, you prefer to use a different label, that's fine with me, so long as we know what we're referring to.
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#39161 - 07/24/11 10:47 PM Re: Light From Distant Galaxies. [Re: Bill S.]
Bill Offline
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I would say that "infinity" is more a quality than a thing. Infinity is a concept that changes with what you are talking about. If you are talking about time when you say infinity you mean unending time, if you are talking about space, then you mean unending space, if you are talking mathematics then you mean an unending count of whatever concept you are talking about, such as the infinite number of integers.

Checking my dictionary (Websters' II New Riverside University Dictionary, 1984) I find that infinity is a noun, (1) "The quality or state of being infinite".

Bill Gill
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#39164 - 07/25/11 01:16 PM Re: Light From Distant Galaxies. [Re: Bill]
Bill S. Offline
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Quote:
Something eternal exists outside time; by contrast, something sempiternal exists throughout an infinite time.


Anyone else find this a bit incongruous?

It seems to make a distinction between eternal and sempeternal, but the reasoning is circular, and we end up with infinite time, in spite of the assertion that "eternal exists outside time".
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#39165 - 07/25/11 01:26 PM Re: Light From Distant Galaxies. [Re: Bill S.]
Bill S. Offline
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Consider eternity, space and time. Relativity tells us that space and time are different dimensions of the same thing: spacetime.

Could it be that eternity is a superposition of space and time, such that it is neither until we try to “measure” it; then either the spatial or temporal aspect emerges, depending on what question is asked?

Just a thought.
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#39169 - 07/26/11 01:24 AM Re: Light From Distant Galaxies. [Re: Bill S.]
Bill 6 Offline
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Apropos the tired light theory; in another ng I happened across a comment in Wikipedia re the Pound-Rebka experiment -

Quote:
Normally, when an atom emits or absorbs a photon, it also moves (recoils) a little, which takes away some energy from the photon due to the principle of conservation of momentum.

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#39170 - 07/26/11 02:41 AM Re: Light From Distant Galaxies. [Re: Bill 6]
Orac Offline
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Yes ... keep reading that explaination

Quote:

Special Relativity predicts a Doppler redshift ...

On the other hand, General Relativity predicts a gravitational blueshift of ....

Rebka countered the gravitational blueshift by moving the emittor away from the receiver, thus generating a relativistic Doppler redshift:

The detector at the bottom sees a superposition of the two effects ....


That was the original problem if the universe wasn't expanding we would expect to see red shifts, blue shifts and nuetral galaxies which we don't .. we see only red.
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#39175 - 07/26/11 05:33 AM Re: Light From Distant Galaxies. [Re: Orac]
Bill 6 Offline
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Originally Posted By: Orac
That was the original problem if the universe wasn't expanding we would expect to see red shifts, blue shifts and nuetral galaxies which we don't .. we see only red.

We only (predominantly) see redshift because there are vast, free matter permeated, spaces between us and ALL of those galaxies!

We would expect to see red shifts, blue shifts and neutral galaxies in a non-expanding universe ONLY if there were NO random atoms scattered between us and those galaxies.

ALL of the light emitted by ALL of those galaxies has effectively traveled through a medium the atoms of which have absorbed the original photons then emitted their own photons resulting in the aforesaid loss of energy.

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#39178 - 07/26/11 09:30 AM Re: Light From Distant Galaxies. [Re: Bill 6]
Orac Offline
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I think this goes back the Pound-Rebeka experiment and gives the theory a problem Bill 6

Quote:

If the photon's frequency and energy is different by even a little, the atom cannot absorb it (this is the basis of quantum theory).


Thats the proposed mechanism by which we lose photons when it goes through a media like your glass you mentioned and it gets hot. In this media we dont see "tired light" we see the same light minus some lost photons.

Might think and look around because I am sure there would be an experiment that could be done with a media to deliberately bleed some energy of the excited atmoic state of the media. Prediction would be you get less light (photons out) when you drain the energy out as opposed to a different frequency light which is what I am thinking tired light theory would predict if I am interpretting properly.

So something like an ant-laser (http://spectrum.ieee.org/semiconductors/optoelectronics/antilaser-invented) but where we are draining energy ... lets see what we can find.


Edited by Orac (07/26/11 09:48 AM)
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#39179 - 07/26/11 10:07 AM Re: Light From Distant Galaxies. [Re: Orac]
Orac Offline
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Sigh I am so silly it's essentially what happens with doppler cooling (laser cooling) ... didn't think about it till I started searching.

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

Quote:

Doppler cooling involves light whose frequency is tuned slightly below an electronic transition in an atom. Because the light is detuned to the "red" (i.e. at lower frequency) of the transition, the atoms will absorb more photons if they move towards the light source, due to the Doppler effect


I think that covers the basics for tired light.
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#39180 - 07/26/11 12:03 PM Re: Light From Distant Galaxies. [Re: Orac]
Bill S. Offline
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Good thing we have Bill 6 and Orac to bring us back on track when we start wandering off into infinity. Perhaps we should start an infinite thread. smile
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#39182 - 07/26/11 02:09 PM Re: Light From Distant Galaxies. [Re: Bill S.]
Bill Offline
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Originally Posted By: Bill S.
Perhaps we should start an infinite thread.

We already have an infinite thread. Have you looked at the Philosophy of Religions thread in NQS?

Bill Gill
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#39188 - 07/26/11 03:46 PM Re: Light From Distant Galaxies. [Re: Bill]
Bill S. Offline
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Quote:
Have you looked at the Philosophy of Religions thread in NQS?


I have. In fact I have made a few contributions. It would be interesting to know how many of the 2.5m hits were Rev. smile
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#39201 - 07/27/11 07:35 AM Re: Light From Distant Galaxies. [Re: Orac]
Bill 6 Offline
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Originally Posted By: Orac
Quote:

Doppler cooling involves light whose frequency is tuned slightly below an electronic transition in an atom. Because the light is detuned to the "red" (i.e. at lower frequency) of the transition, the atoms will absorb more photons if they move towards the light source, due to the Doppler effect


I think that covers the basics for tired light.

What do you mean by that comment?

The light from various galaxies encounter atoms that are moving toward and away from the galaxies so presumably the number of photons absorbed will balance out however as I have pointed out on several occasions.. the redshift of the light from distant galaxies is in no way related to the number of photons that reach us!

Challenges to the tired light concept based on the scattering, or otherwise reduction in the number, of photons arriving at our location are either examples of deliberate disinformation or of ignorance.


Edited by Bill 6 (07/27/11 07:45 AM)

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#39206 - 07/28/11 06:07 AM Re: Light From Distant Galaxies. [Re: Bill 6]
Orac Offline
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The problem is we can show that we have never seen an absorbtion an retranmission at anything other than the original frequency ... quantum behaviour of the electron shell behaviour sort of demands it.

If it doesn't retranmit the photon the atom that absorbed it has more energy .. ergo it gets hotter. Ergo space not being a perfect vaccuum is also above absolute zero even in its futherest points due to the above.

Unless you can cite an example where an atom absorbs one frequency and retransmits another based on energy drain while the atom was in the excitation state I am not sure where you are going with this.

I am not trying to disinform or make any assertions here ... I am willing to believe you just at the moment it is not probable unless you can provide an example.

I can't proove that it couldn't occur because you aren't breaking any physics laws but just pointing out you are asking us to belive something we have never seen and should have really if it were so.

Edit: I should say I am not saying I understand light or cosmology any better than you and I certainly have no theory on how it all works. Every theory I have seen so far has problems with it ... I am just asking and probing questions around tired light.


Edited by Orac (07/28/11 06:40 AM)
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#39213 - 07/29/11 12:40 AM Re: Light From Distant Galaxies. [Re: Orac]
Bill 6 Offline
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Originally Posted By: Orac
The problem is we can show that we have never seen an absorbtion an retranmission at anything other than the original frequency ... quantum behaviour of the electron shell behaviour sort of demands it.

The quote from Wikipedia re the Pound-Rebka article posits an energy loss by the photon that has nothing to do with its original frequency nor that of the absorbing/emitting atom -

Originally Posted By: ”Wiki”
Normally, when an atom emits or absorbs a photon, it also moves (recoils) a little, which takes away some energy from the photon due to the principle of conservation of momentum.

Your response intimated that I had taken that quote out of context however the lines that you supplied made no changes to the context of that sentence.

Quote:
If it doesn't retranmit the photon the atom that absorbed it has more energy .. ergo it gets hotter. Ergo space not being a perfect vaccuum is also above absolute zero even in its futherest points due to the above.

According to the Wiki quote the atom moves when it emits its own photon and I am of the opinion that because it moves it incurs an increase in temperature.

There are no ‘furtherest points’ in the universe. All locations are equivalent.

Quote:
Unless you can cite an example where an atom absorbs one frequency and retransmits another based on energy drain while the atom was in the excitation state I am not sure where you are going with this.

I have already cited an example with the Wiki quote - above. The retransmitted photon loses energy in accordance with the conservation of momentum concept as the atom progresses from its excitation state.

Quote:
I am not trying to disinform or make any assertions here ...

There have been several claims in this thread that a reduction in the number of photons arriving here due to scattering explains redshift and although I have pointed out that this is a nonsense you continue to make that claim. As far as I am concerned this is an example of disinformation.

Quote:
I can't proove that it couldn't occur because you aren't breaking any physics laws but just pointing out you are asking us to belive something we have never seen and should have really if it were so.

We have seen the phenomenon - light from distant galaxies is redshifted. As to why this is so... we have the above explanation from Wiki.

I had hoped that perhaps an experiment (such as the one that I suggested where a beam of light is projected horizontally through a lake) had been carried out but presumably this has never been done and, due to the fact that it could introduce another challenge to the big bang theory, authorities will ensure that it remains untested.

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#39215 - 07/29/11 03:07 AM Re: Light From Distant Galaxies. [Re: Bill 6]
Orac Offline
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Originally Posted By: Bill 6
The quote from Wikipedia re the Pound-Rebka article posits an energy loss by the photon that has nothing to do with its original frequency nor that of the absorbing/emitting atom -

Normally, when an atom emits or absorbs a photon, it also moves (recoils) a little, which takes away some energy from the photon due to the principle of conservation of momentum.

Your response intimated that I had taken that quote out of context however the lines that you supplied made no changes to the context of that sentence.


No you are doing it by ommission instead ... because they go on to say and you choose to ignore in that same article and page.

Quote:

When the same atom in its base state encounters a photon with that same frequency and energy, it will absorb that photon and transit to the excited state. If the photon's frequency and energy is different by even a little, the atom cannot absorb it (this is the basis of quantum theory).



Quote:

According to the Wiki quote the atom moves when it emits its own photon and I am of the opinion that because it moves it incurs an increase in temperature.


We totally agree and I am saying the same thing a different way.

Quote:

There are no ‘furtherest points’ in the universe. All locations are equivalent.


Lets say a point along way between the nearest sun or galaxy then ... exact position is not important here.


Quote:

I have already cited an example with the Wiki quote - above. The retransmitted photon loses energy in accordance with the conservation of momentum concept as the atom progresses from its excitation state.


Sorry that same article explicitely told you the frequency would be unchanged ... you choose not to read or accept it.


Quote:
There have been several claims in this thread that a reduction in the number of photons arriving here due to scattering explains redshift and although I have pointed out that this is a nonsense you continue to make that claim. As far as I am concerned this is an example of disinformation.


I am absolutely stumped understanding how a process you described on a physics website leads to a redshift and and simplying asking from clarification but that is somehow disinformation.

I am making absolutely no claims of anything I am asking questions???

Quote:
We have seen the phenomenon - light from distant galaxies is redshifted. As to why this is so... we have the above explanation from Wiki.


As I have said but you choose to leave out part of the explaination.


Quote:

I had hoped that perhaps an experiment (such as the one that I suggested where a beam of light is projected horizontally through a lake) had been carried out


It will have been done through very many media over vast distances ... I can even tell you I can give you a result better than that, there is a laser project that bounces a beam off a mirror surface left on the moon.

What is it in particular you want to see the original spectrum and the resultant return?


Quote:

but presumably this has never been done and, due to the fact that it could introduce another challenge to the big bang theory, authorities will ensure that it remains untested.


It will have been done and many times. Sorry I like many scientists don't just accept big bang or inflation I am by nature extremely skeptical.

Is your opposition to big bang religious or scientific and I ask only because you seem to be somewhat hard on science in general.


Edited by Orac (07/29/11 03:11 AM)
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