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ulenrich
2009-Jun-09, 02:13 PM
We aim a laserlight cannon at one liter of water 20 C warm.
We adjust the time the laser fires to get this water boiling.
Now the test:
The water moves away with half the velosity of light. We fire the laser exactly the same time period as above.
The water gets boiled?

This is a deciding question for my theory at
http://www.bautforum.com/against-mainstream/88736-expansion-universe-photons-2.html#post1502957

Amber Robot
2009-Jun-09, 03:45 PM
Well, barring the fact that you'd be hard-pressed to get water to travel at the speed of light, the wavelength of the laser that the water would experience would be a function of the relative velocity between the laser source and the water. Therefore, the energy of the laser would be less in the water's frame than in the laser's frame, so above some speed the laser light retrieved would no longer have enough energy to boil the water. Am I missing something?

antoniseb
2009-Jun-09, 04:09 PM
It is also worth noting that ulenrich is assuming that the same number of photons will hit the bucket. It is worth noting that without taking time dilation into account, the burst will take twice as long, giving the bucket a bit more time to cool off while being hit.

ulenrich
2009-Jun-09, 04:41 PM
It is also worth noting that ulenrich is assuming that the same number of photons will hit the bucket.

yes


It is worth noting that without taking time dilation into account, the burst will take twice as long,
yes


giving the bucket a bit more time to cool off while being hit.
No, i am not interested in these effects. It is a thought experiment with ideal circumstances (some heat keeping isolations...)

My question is all about:
Does the red-shifting space expansion effects of the universe infringe the law of conservation of energy. I guess yes, and my ATM theory wants this law to be healed...

As Amber points out

... energy of the laser would be less in the water's frame than in the laser's frame
Because there is no chance to restore the frame to all redshifting directions at once ....

cjameshuff
2009-Jun-09, 09:15 PM
No...the energy of the beam is unchanged. Its power is decreased consistent with the red shifting, but as antoniseb pointed out its duration in the frame of the water increases. At a parting velocity of a bit less than 0.5c where doppler and relativistic effects add up to a red shift of 0.5, a 1 joule, 1 watt, 1 second pulse of 400 nm blue/UV light in the frame of the laser would be received as a 1 joule, 0.5 watt, 2 second pulse of 800 nm deep red/near IR.

Amber Robot
2009-Jun-09, 10:36 PM
I think in photons.

WayneFrancis
2009-Jun-09, 11:13 PM
Well, barring the fact that you'd be hard-pressed to get water to travel at the speed of light, the wavelength of the laser that the water would experience would be a function of the relative velocity between the laser source and the water. Therefore, the energy of the laser would be less in the water's frame than in the laser's frame, so above some speed the laser light retrieved would no longer have enough energy to boil the water. Am I missing something?

Add to this that is the non accelerated reference frame the water would have higher mass and thus would take more energy to boil...

WayneFrancis
2009-Jun-09, 11:22 PM
...
No, i am not interested in these effects. It is a thought experiment with ideal circumstances (some heat keeping isolations...)
...

Let me point out that what you are talking about is not "ideal" circumstances it is ignoring laws of physics. Develop your ATM theory but if you don't take into account stuff like heat dissipation over the time period of the experiment then your ATM theory will be fundamentally flawed from the get go.

ulenrich
2009-Jun-09, 11:46 PM
No...the energy of the beam is unchanged. Its power is decreased consistent with the red shifting, but as antoniseb pointed out its duration in the frame of the water increases. At a parting velocity of a bit less than 0.5c where doppler and relativistic effects add up to a red shift of 0.5,

a 1 joule, 1 watt, 1 second pulse of 400 nm blue/UV light in the frame of the laser would be received as
a 1 joule, 0.5 watt, 2 second pulse of 800 nm deep red/near IR.

1w * 1s = 0.5 w * 2s
So there is not less energy reaching the water ?
That would make my ATM theory at
http://www.bautforum.com/against-mainstream/88736-expansion-universe-photons-2.html
obsolet !

I thought it is somehow like velosity when driving: double the speed and you have 4 times the energy if crashing the car, which would be in our example like: 0.25w * 2s

snowflakeuniverse
2009-Jun-10, 01:13 AM
Hi Ulenrich

Your are right, there is a loss of energy.

The expansion of spacetime does “violate” conservation of energy. However, if the expansion of spacetime were reversed, that energy would be returned, so the energy is not technically lost, if one adopts a larger perspective.

For those who think the energy is preserved within our observable spacetime, consider the following example.

One photon travels through an expanding spacetime field. As it travels through the expanding spacetime field, its wavelength is increased, and it’s energy is diminished. When the photon hits some object, (your pot of water), the energy the photon imparts is less than what the photon started off with.

Snowflake

ulenrich
2009-Jun-10, 10:07 AM
... consider the following example.

One photon travels through an expanding spacetime field. As it travels through the expanding spacetime field, its wavelength is increased, and it’s energy is diminished. When the photon hits some object, (your pot of water), the energy the photon imparts is less than what the photon started off with.

So, from a quantum mechanically perspective, as every photon is streched and looses energy: The experiment will have the answer: No, the water does not get boiled!

But the answer of cjameshuff looks to me like he has a generally accepted formular at hand. Are there any real experiments which are testing if light functions as a wave or particle in this case?

PS to snowflakeuniverse:
As Your theory tries to handle the same problem of this "violation" but my theory tries it to explain very different than Yours, I would be very lucky to have a comment from you at:
http://www.bautforum.com/against-mainstream/88736-expansion-universe-photons.html

snowflakeuniverse
2009-Jun-10, 01:26 PM
Hi Ulenrich

cjameshuff’s response
You seem to take the response of cjameshuff as representing the mainstream belief. The answer or relationship in which energy is conserved is not correct, at least if one believes in general relativity and the expansion of spacetime. Cjameshuff’s response is NOT the “mainstream answer”, nor does it conform to observation.

cost of expansion
Expansion comes at a cost. Any system that is expanded experiences a loss of energy. Take a balloon, expand it by reducing the surface tension. The temperature of the balloon will drop. Photons traveling through an expanding spacetime field pay the cost by loosing energy.

creating photons
In order for Cjameshuff’s answer to be correct, there would have to be some kind of spontaneous creation of photons while the photons traveled through the expanding spacetime field. (This would be an “Against the Mainstream” belief). If this happened, the generation of these extra photons would alter the observed flux rate, which would alter the observed luminosity of distant galaxies. If this were true, distant galaxies and quasars would be brighter than they should be and they would have to be further away than presently assumed.

It is an interesting theory and it may be right, but it is not a mainstream answer, which is what is expected in this “ask the expert” forum.


Snowflake

Jeff Root
2009-Jun-10, 03:08 PM
snowflakeuniverse,

The pulse of laser light has reduced energy relative to the water which
is moving away from the laser light source, but its energy is not reduced
relative to that source. If I were to slow the moving water so that it
is no longer moving relative to the light source, the relative energy of
the light pulse would be restored.

Energy isn't lost in the expansion. The energy of the redshifted light
is converted into gravitational potential energy, in addition to being
more spread out. The background radiation billions of light-years away
from us is much more energetic relative to us than the radiation we see.
And the radiation we see is much more energetic relative to observers
in a galaxy billions of light-years away than it is to us.

Although the energy isn't lost from the Universe, it does become less and
less accessible to individuals.

-- Jeff, in Minneapolis

Jeff Root
2009-Jun-10, 03:17 PM
ulenrich,

The water cools by radiation. No insulation can prevent that. The water
has to be exposed to the laser beam. Where it is exposed, it radiates as
well as absorbs. Antoniseb is correct that the water cools more when it
is moving away from the laser cannon than when it isn't moving away.

-- Jeff, in Minneapolis

Jeff Root
2009-Jun-10, 03:28 PM
Wayne,

The description of mass changing with relative speed was dropped from
relativity theory decades ago (by Einstein, I believe) in favor of referring
instead to the changing momentum and energy. The idea that the mass
changes can be dropped without losing anything.

-- Jeff, in Minneapolis

Ken G
2009-Jun-10, 03:38 PM
ulenrich,

The water cools by radiation. No insulation can prevent that. Actually, ulenrich is correct that this particular issue can easily be mitigated to make it a non-issue, to concentrate on the other question of interest. All one needs to do is insulate the water except where the laser comes in, and then the re-emission of heat by the water would only become the least bit significant at temperatures far greater than the boiling point of water. In the limit of a very small opening and a very bright laser, one can make the cooling effect as insignificant as you like, in the full spirit of how physical gedankenexperiments are created, energy in GR is extremely subtle.

On the issue of conservation of energy in an expanding universe, I'm not expert enough on general relativity to comment on your answer about that, except to say that the standard answer is that general relativity does not need to conserve energy, as energy is a coordinate-dependent concept, and also to point out that general relativistic explanations from non-experts generally vary from partially incorrect to completely incorrect. Which applies in this case I am not an expert enough myself to say.

ulenrich
2009-Jun-11, 12:45 AM
snowflakeuniverse,

The pulse of laser light has reduced energy relative to the water which
is moving away from the laser light source, but its energy is not reduced
relative to that source. If I were to slow the moving water so that it
is no longer moving relative to the light source, the relative energy of
the light pulse would be restored.

Now we vary the experiment: We move the lasercannon away instead the water. Which is equivalent to the aim of the experiment in terms of Einsteins Relativity. And this solves any questions about varying "mass" of the liter water.

Therfore the energy of the light is reduced "relative to that source"

Now the redshift in the universe, also this light is reduced "relative to that source" in energy.
Think of how the redshift happens!
Not by moving something, but by adding additional space elements right inside the photons.
To show you with the help of letters:

If "UM" is a photon on its way "-" as space:
----------------UM---------------------
After redshift this photon looks like:
------------------U-M------------------
Because the redshift happens by adding space right inside the photon!

Therefore also for the light source the energy of the photon is reduced by redshifting in our universe, so it is a violation of the Conservation of Energy Law!

PS: the experiment is a "Gedankenexperiment". You do not have to take water. You can take any chemical substance which shows some better results pehaps at -240 Degree Celsius ...

snowflakeuniverse
2009-Jun-11, 12:57 AM
Hi Jeff Root,

General Relativity and an expanding universe predicts that Energy is lost,

Jeff you said,
The pulse of laser light has reduced energy relative to the water, which
is moving away from the laser light source, but its energy is not reduced
relative to that source.

Lets say we put a mirror on a very distant galaxy and we shoot a laser at a mirror on the distant galaxy. The mirror bounces the light back to us and after a billion years the light comes back to us. The light received will not come back with the same amount of energy we sent it off with. The energy is reduced relative to the original source.

Now you might want to argue that the motion of the mirror on the galaxy imparts a Doppler shift and it is at that point energy is lost. This argument would also be false, (if general relativity is right and the expansion of the universe models are right).

Expansion comes at a cost and energy is “lost” from our, or anyone’s observable spacetime.

You also said,
Energy isn't lost in the expansion. The energy of the redshifted light
is converted into gravitational potential energy, in addition to being
more spread out.

We may be saying somewhat the same thing here but your answer is not correct or at least confusing things.

First, note that I did say that if the expansion of spacetime were reversed, the energy would be imparted back into the photons, so there is in some ways no loss in energy, but this “gravitional potential energy” as you call it, is not available for us to tap into, and if we can not tap into it, it represents a lost energy from our universe.

For example, if the expansion of spacetime continues forever, eventually every photon will have a wavelength so long it will be impossible to utilize the energy of the photon. It’s energy approaches 0. It is impossible to “do work” with something that has 0 value.

Snowflake

snowflakeuniverse
2009-Jun-11, 01:41 AM
Hi Ulenrich

You said
Therefore also for the light source the energy of the photon is reduced by redshifting in our universe, so it is a violation of the Conservation of Energy Law!

This is somewhat true, but your response is also a misleading. Jeff Roots “gravitational potential energy” is an important aspect to consider. If you act as an observer, outside of our Universe, what I have called an “Eye of God” perspective, you would see that the energy of the photon is still there, just “absorbed” in an expanded spacetime field.

Other Arguments
Mass and Energy not equivalent
However, your argument can still have a second life if you want to point out the fact that Energy and mass are no longer equivalent (E = mcc) ie light diminishes in an expanding spacetime field yet mass does not.

Change stops at the speed of light
Also, another point I like to note is as follows. if it is true that as one approaches the speed of light, clocks or physical processes slow down, how can a photon increase its wavelength or lose energy or change if it is traveling at the speed of light?

Snowflake

pzkpfw
2009-Jun-11, 02:02 AM
This is getting beyond a Q&A thread, and into pushing of ATM ideas.

Can we please get back to the OP?

WayneFrancis
2009-Jun-11, 02:10 AM
Wayne,

The description of mass changing with relative speed was dropped from
relativity theory decades ago (by Einstein, I believe) in favor of referring
instead to the changing momentum and energy. The idea that the mass
changes can be dropped without losing anything.

-- Jeff, in Minneapolis

Yup got you, thanks for clearing that up.