Spontaneous Energy Loss in Light

[Les Sleeth]

Originally posted by marcus
Galaxies receding at twice the speed of light and yet no weirdness like tachyons and going backwards in time and killing your grandfather and circus freak infinite energy stuff. All those things are stories told in a Special Relativity surround. . . .

Now this is a REALLY interesting question. . . . It is definitely mysterious. 73 percent of the energy in the U is called "dark energy" and nobody has a convincing theory of what it is and it has never been detected. And the assumption is that the density of it is constant over space and time. So what makes more---to keep the density constant when space expands? [?]

It is one of the questions that make life worth living. I mean it.

Thanks for clarifying the speed thing . . . I can see why (I think) that expanding space causing recession faster than c isn't a problem.

This thread was really my round-about way of asking about the creation of space. I'd wondered if light moving ahead of matter expansion on the horizon might be doing it; and if so, and if light were losing energy over time, then if the integrity of new "space" might suffer too. You said that the light inside our universe is stretching and losing energy as it does, but I suppose that would not necessarily apply to the light leading expansion.

Yet apparently no one understands what is creating space. You seem resistant to instilling space with qualities, yet in addition to the other properties I mentioned it is powerful enough to move galaxies apart faster than the speed of light! That is why I suspect there is more to space than most seem to want to credit it with.

For example, usually it is said that acceleration or mass produces the gravity effect. But might not gravity be a property of space? That is, when there is a concentration of energy, such as the energy concentrated to accelerate or the huge amount of energy packed into matter, then that causes space to constrict. The higher the concentration of energy, the more the constriction.

The constancy of light speed too could be due to a certain tension space maintains of which light speed reflects. I always wondered why light and atoms oscillate rhythmically. A guitar string only does so, for instance, when it is under a certain degree of tension; without that minimum tension it flops around chaotically when plucked.

Both light speed and gravity could be the result of a single type of polarized tension of space, a divergent-convergent polarity. So when something reaches the density of light, the divergent side sends it off at light speed (rhythmically oscillating from the push-pull of the polarity), and when something exhibits more than that density, the convergent side kicks in constricting in on it.

These obviously are speculations of a "why" person; you can already tell I am not properly versed in the "how." I probably better cool it before a mentor transfers this thread to theory development!

Thanks for the interesting discussion so far. I am enjoying the heck out of it.

 

[Royce]

Les, first to clear one point up that, as I understand it, marcus doesn't quite explain right. No one or nothing is creating space. Spacetime itself is expanding as marcus said but one cubic meter prior to the expansion is still one cubic meter after expansion because the meter would expand with space. The way we measure the expansion is the red shift of the light emitted by galaxies far away. As it take millions of years, even billions of years for the light to get to us, a significant amount of expansion takes place. Also the further apart we are, the faster we recede from one another. As space expands the wavelength of the light also expands changing the period of the wave, the wavelength become longer, lower in frequency and thus red shifted. Some galaxies are so far away that the light from it has shifted beyound even infared to radiowaves and can only be detected by radio telescopes.

I've thought about your last question quite a bit lately. If the universe is expanding into dimensionlss, timeless space what would happen if a photo left our sace time and went into the void? I have no way of proving this and it is only speculation on my part but if it did happen then the photon would no longer have any velocity or momentum as V and M are meaningless in such a void or nul-space as I call it. If a photon or EM wave had no velocity it could no longer be a photon or EM wave and would instantly turn into matter, probably a string which is energy vibrating in a dimensional loop.
This would of cours be creating at least one dimention and that area of the void would no longer be dimensionless and therefore be spacetime. This would be creating spacetime in the sense that I think you mean. As I said this is pure speculation on my part.

 

[Les Sleeth]

Originally posted by Royce
Les, first to clear one point up that, as I understand it, marcus doesn't quite explain right. No one or nothing is creating space. Spacetime itself is expanding as marcus said but one cubic meter prior to the expansion is still one cubic meter after expansion because the meter would expand with space.

Yes, that's pretty much how I see it -- I think it has been me that's used the word "create." A better term would probably be "determine," to describe what I'm asking. To me there seems to be a bit of a contradiction in the ambiguity in the definition of space.

If space is a void, then what is it expanding into? If someone says there is nothing there, not even space, then space is clearly of a different nature from nothing -- it is "something." It can serve as the medium for matter, for instance. Where matter isn't, seems to be what is being referred to as "nothing."

I've been trying to understand what makes space different from "nothing." As the universe expands, what exactly differentiates space from the nothing it is expanding into? Matter? But then, I wondered about the light going on ahead of it, does that determine the nothing has now become "space"? Or is more required, something else that is expanding along with light, that defines/determines space?

 

[Royce]

In a word, Dimensions. That is the difference between space and nothing or void or my nul-space. There are a number of people other than me who think that matter is what makes its spacetime. matter gane only exist in spacetime and if string theory is correct tthen matter in the form of strings is energy vibrating within a loop of a dimesion. Someone figured out that it would only take 28 dimensions to account for everything that exist. I think that the number is now down to 11.
One other thing about what I previously posted. It is speculated that while the universe is expanding it might still be a singularity or perhaps better a black hole. As such no photons could escape our universe and so no more space could be created.
This is about as far as I can go or the pain starts. I run into the same problem with Quantum Mechanics.

 

[marcus]

Hello Royce, Sleeth,
it seems a shame to quibble about one point---I like a lot of your speculation and agree with some of the background science you point to---but one of the hardest things to understand is that even tho on the large scale space is expanding the sizes of ATOMS don't grow.

Indeed in the picture of expansion cosmologists give us----*galaxies* don't get bigger they just get farther apart.

Even local clusters of galaxies can overcome expansion and stay together if they attract each other enough. A good cohesive cluster of galaxies falls back together and overcomes expansion. So it doesn't get disassembled. But that is a grey area---for the most part galaxies drift apart (but because within themselves they are securely gravitationally bound, they stay the same size)

the basic modules of life retain their integrity even tho largescale things drift apart

In fact if you see a photo of a redshift z=2 galaxy that means space has expanded by a factor of 1+z, or 3, since the light left it. And that galaxy is to all intents and purposes just a usual-looking thing. The expansion of space hasnt made US NOW significantly different from IT THEN. Other things may be different. But it is not smaller just on acount of living in an epoch when space hadnt expanded yet by that factor of 3.

We know not to worry about expansion effecting things on a local, solar system, or even Milky Way, scale.
And meters are not effected.

So a distance of a trillion meters, after space has expanded by a factor of two, becomes 2 trillion meters.

If atoms don't change size, then you wouldn't expect metersticks to change either----the size of our units of measurement is not linked to this largescale intergalactic distance expansion process.

Not to say I or anyone really understands this expansion---but simply that's how the prevailing model looks. Sorry if it seems inconsistent that only some things expand and other things dont---I realize the unintuitive aspect here.

Must go. Hope not too much of a ramble.

(of course just because a model happens to be the prevailing one at the time doesn't mean it is the ultimate truth! but still worth reporting I think)

 

[marcus]

must also add that there are people who
because of an observed speeding up of the expansion rate
have projected this acceleration hundreds of billions of
years---very far, don't remember---into the future and
come up with scenarios in which familiar entities like
galaxies are pulled apart

expansion becomes so rapid as to overcome their
integrity as gravitationally bound systems
their gravity is no longer able to fight it

and even worse, modules even smaller than galaxies are
pulled apart. I don't find these speculative scenarios interesting
or appealing

this is just a kind of linear projection taken to extremes
we don't know much about the dark energy responsible for
accelerated expansion---not enough to project how it will
be far in the future. pretty much pure speculation and not
to worry about

for the foreseeable future nothing of any consequence expands
except the largescale distances between galaxies and the wavelengths of the light traveling across those wide reaches of space. atoms and
metersticks stay the same size (paradoxically one might say)
if I have given a distorted picture perhaps someone else will
correct it.

 

[Les Sleeth]

Originally posted by marcus
must also add that there are people who
because of an observed speeding up of the expansion rate
have projected this acceleration hundreds of billions of
years---very far, don't remember---into the future and
come up with scenarios in which familiar entities like
galaxies are pulled apart . . . expansion becomes so rapid as to overcome their integrity as gravitationally bound systems
their gravity is no longer able to fight it . . . we don't know much about the dark energy responsible for accelerated expansion---not enough to project how it will be far in the future. pretty much pure speculation and not to worry about

Thank you Marcus and Royce for the thoughts and information.

In some threads I've seen people discuss the possiblity that the universe will expand forever. I always felt they overlooked the fact that the universe is also coming apart. It is expanding and radiating away, losing structural integrity. And possibly after some 10^50 years when most present protons should be taking a turn for the worse, the universe may become just someplace where it all used to be.

If we could travel ahead in time and observe this place, I wonder what there would be. Trying to imagine this is partially why I asked the question of this thread (i.e., if light spontaneously loses energy). I've wondered if we might not find a vast area something similar to cosmic background radiation.

It wouldn't quite be like background radiation however because it would be a lot more "stretched out" than it is now. That is, it would have lost virtually all its energy and so have elongated so much it would be oscillating far too subtly for any equipment we currently have to detect.

 

[Royce]

Yeah, Les, total entropy. I've read other speculations about it. Eventually the universe would look like the COBE background. I find that hard to imagine. Wouldn't gravity keep cold chunks of rock held in place at least locally? I sure don't know.

 

[Alexander]

Originally posted by Royce
Les, first to clear one point up that, as I understand it, marcus doesn't quite explain right. No one or nothing is creating space. Spacetime itself is expanding as marcus said but one cubic meter prior to the expansion is still one cubic meter after expansion because the meter would expand with space. The way we measure the expansion is the red shift of the light emitted by galaxies far away.

No, meter stick is not expanding with space because e/m interaction (atoms holding meter stick) is independent of space expansion.

By the same reason a photon does not stretch with expansion of space, Marcus is wrong here, energy of photon conserves, thus frequency and wavelength too (in vacuum). Redshift of distant galaxis is just due to fact that they are moving away from us due to space expansion (Doppler shift due to coordinate transformation).

 

[marcus]

Royce, I certainly do admire your signature quote

>>As always with respect,

>>Royce

>>"If you find yourself arguing with a fool, then the chances are
>> that he is doing the same thing."

 

[Les Sleeth]

Originally posted by Alexander
. . . Marcus is wrong here, energy of photon conserves, thus frequency and wavelength too (in vacuum). Redshift of distant galaxis is just due to fact that they are moving away from us due to space expansion (Doppler shift due to coordinate transformation).

Well, I wish somebody would clear this up, I am very interested in knowing. Is this a dispute that is going on among cosmologists, or is there consensus? Other opinions would be welcome.

Alexander, from my understanding of what Marcus said, it didn't seem to me that he was disputing that the reshift observed from distant galaxies is due to the Doppler effect.

 

[marcus]

Originally posted by LW Sleeth
Well, I wish somebody would clear this up, I am very interested in knowing. Is this a dispute that is going on among cosmologists, or is there consensus? Other opinions would be welcome.

Alexander, from my understanding of what Marcus said, it didn't seem to me that he was disputing that the reshift observed from distant galaxies is due to the Doppler effect.

You might get into it at the level of a classic textbook like
Frank Shu
The Physical Universe: An Introduction to Astronomy
1982

He is a senior guy in the department at UC Berkeley.

Or another guy at Berkeley, Eric Linder, since he has some
notes online called Cosmology Overview. I would take his
FAQ for the layman with a grain of salt since very popularized
but his Cosmology Overview here is OK:

http://panisse.lbl.gov/~evlinder/lcos.pdf

I don't know any mainstream cosmologists who would agree with Alexander that the cosmological redshift is best viewed as a doppler shift.

Frank Shu warns strongly against interpreting (cosmological) z as a doppler shift because it is a common cause of confusion.
He draws a couple of diagrams (pages 373, 374) and goes into a couple of pages of discussion to make sure students understand.

EM wave propagation, Maxwells eqns, takes place in space and tiny changes in metric have a cumulative effect. Shu uses the
figurative way of describing it that I do---he says it is better to think of it as wavelengths being "stretched out" than to picture it due to Doppler.

Linder takes it for granted that the (cosmological) 1+ z is simply the ratio of the scale factors a(t) at emission time and reception time----nothing to do with velocity of emitter at time of emission.

the formula he presents (a non-doppler) is the one all cosmologists use that I have ever seen

1+z = a(t_rec)/a(t_em)

a(t) is the parameter in the metric that keeps track of the expansion of space. The Hubble parameter changes with time
and is defined as the time derivative of a(t) divided by a(t).

That is, essentially the time-rate of expansion but as a fraction of current size.

da/dt divided by a

That is just how everybody defines the Hubble parameter and
the usual metric is R-W defined using a(t) and
the consensus formula for cosmological redshift (as distinct from individual motion doppler) is this ratio involving a(t) I told you.

People will say different things when they POPULARIZE but what I am saying is, I believe, very consensus mainstream cosmologists' view of cosmo redshift.

Alexander's viewpoint is highly eccentric or reflects a deep misconception. Dont understand his continual repetition of it.

Anyway he is welcome to see it as Doppler---that way is very common in newspapers and popular books because more easily understood by non-technicals.

But try to understand it as a stretching out as space expands
and eventually things will make better sense to you. Promise

 

[heisenberg]

Hi, I am new! so hi to everyone

I guess a photon could spontainiously lose energy, if it coincidentally collided with a virtual particle, that is created along its trejectory.

The photon would recoil and lose energy, in accord with the compton effect! But would be
deflected at some unknown agngle!

The lost energy of the photon, would have to create a new photon of a longer wavelength.
As it recoiled with the virtual particle. Before the virtual particle disappeared again!

 

[Les Sleeth]

Originally posted by marcus
But try to understand it as a stretching out as space expands
and eventually things will make better sense to you. Promise

Thanks. Actually as you explain it is exactly how I want to see it since it coincides with a little theory I have. I don't mind doing my homework but it is difficult for laypersons to find much discussion of such things in language we can understand.

I have a hypothetical for you, which I will ask in two parts. Part I: How far do you think light might "stretch." Say 10^100 years from now the matter of the universe has radiated away its energy, and so all that is left is a vast continuum of cosmic radiation. I realize according to what you've said light's energy could eternally decrease incrementally, but what if light has a base state where it blends into one huge subtle wave.

Part II: Now imagine this vast continuum reversing its direction, so that base state light begins to converge on a point until it reaches some critical degree of convergence and explodes. In other words, might not the universe be the result of light caught up in a cycle of convergence and divergence?

 

[marcus]

Originally posted by LW Sleeth


I have a hypothetical for you, which I will ask in two parts. Part I: How far do you think light might "stretch." Say 10^100 years from now the matter of the universe has radiated away its energy, and so all that is left is a vast continuum of cosmic radiation. I realize according to what you've said light's energy could eternally decrease incrementally, but what if light has a base state where it blends into one huge subtle wave.

Part II: Now imagine this vast continuum reversing its direction, so that base state light begins to converge on a point until it reaches some critical degree of convergence and explodes. In other words, might not the universe be the result of light caught up in a cycle of convergence and divergence?

I. Light that is redshifted enough becomes undectable. We both are contemplating this.
You came up with a nice image of it----the light is dissolving into the vacuum-----is reabsorbed by the universe.
But a spoilsport with a lame imagination might prefer to look at it as the light's energy just goes to zero---it fades out of existence---as it is progressively more and more redshifted.
All I can do here is what I always try to do----look at the same thing both ways: in a cold objective light and also in figurative imagery, and to refuse to choose between them.

II. I have not heard any evidence that the universe is slated to recompress itself and its light.

The sparsity of matter and the observed spatial flatness suggest boundless expansion.

But IF it were start falling back together all the stretched-out-to-almost-nothing light would start coming back to life.

The CMB which is now 2.725 kelvin was once upon time 3000 kelvin. This 2.725 kelvin is the basic temperature of space (now). If the universe were to collapse the basic temperature of space would rise to
3000 kelvin (less than the surface of the sun but more than the tungsten filament of a 100watt lightbulb) as it was in its beginning.

And that wouldn't even be the end of it----the CMB was emitted after the universe had existed 300 thousand years. So when 3000 kelvin were reached there would still be 300 thousand years left to continue collapsing. The temperature would keep on rising. Space would be like the inside of a star.

To be fully human I expect one must try to look at these things both skeptically and objectively
(there is no suggestion of anything but continued expansion) and also responsively.

You asked about "bounce" scenarios:
dark energy estimated to be 73 percent of the total energy density in the universe is the key to that possibility. there is not enough light. the light could not cause a collapse to "bounce" but dark energy (under certain assumptions) could cause a bounce----ive seen such scenarios plotted out but they are too speculative for me---cant find them interesting. Simply burning up is poetical enough

 

[Les Sleeth]

Originally posted by marcus
Simply burning up is poetical enough

Thanks Marcus, it has been interesting.