Space, Time, The Expanding Universe, and the Speed of Light

[Mamluk]

My first thought is that this conjecture would mean that the light from galaxies 2 billion light-years away would be travelling slower when it reached us, than the light from a galaxy 1 billion light-years away.

In fact, it means that all the light that reaches us would be travelling at different speeds... :shock:

The CMBR would have hardly any speed at all!

This is what I am asserting. Excluding the effect of gravity, light originating from 1 billion light year away would reach earth traveling at a speed of approximately 227,564 km/h while light originating from 2 billion light years away would reach the earth traveling at a speed of approximately 255,336 km/h. The CMBR would indeed hardly have any speed at all.

 

[MeteorWayne]

Unfortunately for your theory, light travels at the same speed in a vacuum, no matter how far away it comes from.

 

[origin]

Mamluk, I answered with esentially the same thing as the above comments to your duplicate post. Just to let you know it is considered bad form to place duplicate posts in different threads...

 

[Mamluk]

Unfortunately for your theory, light travels at the same speed in a vacuum, no matter how far away it comes from.

That is exactly what I am challenging, and yes, I do know what the text books and Einstein say.

 

[Mamluk]

Mamluk, I answered with esentially the same thing as the above comments to your duplicate post. Just to let you know it is considered bad form to place duplicate posts in different threads...

Thank you. I read the rules after the second post, and have apologised to MeteorWayne for it. It won't happen again.

 

[origin]

[Moved from the duplicate post]
The velocity of light can be measured very accurately with an inferometer. Google 'inferometer and speed of light' and check it out. The bottom line is that the speed of light that is coming from any object regardless of it speed, the observers speed or the distance from the observer ALWAYS measures the same speed in a vacuum.

The red shift is due to the wave length change (or frequency change if you like) not a speed change.

 

[SpeedFreek]

Mamluk, you seem to be referring to a variable speed of light cosmology in the duplicate thread.

There is a very big difference between the speed of light varying during the history of the universe (VSL theory), and what you proposed above, which seemed to indicate that we should be receiving light at various speeds, depending on how long it has been travelling for.

With VSL theory, the speed of light is a constant at any given time during the history of the universe, but its value has been changing, and was 60 times faster during the inflationary epoch. VSL is an attempt to solve the horizon problem without invoking inflationary cosmology, but it does not by any means imply a static universe. The universe is expanding, and VSL is only any use as an alternative solution for cosmic inflation, which lasted a fraction of a second.

 

[csmyth3025]

by SpeedFreek » Fri Sep 04, 2009 1:10 pm

In fact, it means that all the light that reaches us would be travelling at different speeds..

There is an interesting article in Wikipedia on the subject of occulation which says, in part:

The term occultation is most frequently used to describe those relatively frequent occasions when the Moon passes in front of a star during the course of its orbital motion around the Earth. Since the Moon has no atmosphere and stars have no appreciable angular size, a star that is occulted by the moon will disappear or reappear very nearly instantaneously on the moon's edge, or limb

To the best of my knowledge there has never been a reported observation of distant objects (such as galaxies) "disappearing" at a later time than (angularly close) nearer stars in our own galaxy. Such an effect would be observable if the light from the distant objects took more time (due to its slower velocity) to reach the Earth from the moon than the light from nearby stars. The same effect would also occur upon the reappearance of these stars and objects.

Does mamluk know of any observations that support his/her hypothesis that light from distant objects reaches us traveling at slower speeds than light from stars in our own galaxy?

Chris

 

[Mamluk]

by SpeedFreek » Fri Sep 04, 2009 1:10 pm

In fact, it means that all the light that reaches us would be travelling at different speeds..

There is an interesting article in Wikipedia on the subject of occulation which says, in part:

The term occultation is most frequently used to describe those relatively frequent occasions when the Moon passes in front of a star during the course of its orbital motion around the Earth. Since the Moon has no atmosphere and stars have no appreciable angular size, a star that is occulted by the moon will disappear or reappear very nearly instantaneously on the moon's edge, or limb

To the best of my knowledge there has never been a reported observation of distant objects (such as galaxies) "disappearing" at a later time than (angularly close) nearer stars in our own galaxy. Such an effect would be observable if the light from the distant objects took more time (due to its slower velocity) to reach the Earth from the moon than the light from nearby stars. The same effect would also occur upon the reappearance of these stars and objects.

Does mamluk know of any observations that support his/her hypothesis that light from distant objects reaches us traveling at slower speeds than light from stars in our own galaxy?

Chris

Hi Chris,

The occultation that you mention above would primarily occur for stars within our galaxy, and as such the speed at which that light travels would be very close to “c” and therefore the observable differences would be negligible. Depending on the orientation of the ecliptic plane of our solar system (the moon’s orbit around the earth is very close to the whole) in relation to the plane of the galaxy, lunar occultation using distant galaxies as reference points may not be feasible. In addition, the same article mentions that time measurements relating to lunar occultations are “timed to an accuracy of a few tenths of a second”, which is wholly inadequate for what we are discussing.

In terms of observations that support my hypothesis, I would like to put a couple forward. Bear in mind that I do know that other factors may be causal in these observations, but I find them interesting, and certainly “supportive” but not “definitive”.

Firstly, a few galaxies on the edge of our observable universe, seems to wander in and out of “sight”. According to the expanding universe hypothesis, the space between us and the distant galaxy would be expanding at around “c”. Once the rate of expansion exceeds “c” we should never be able to see that galaxy again. So, the question is then, does the rate of expansion fluctuate, or does our observable universe periodically contract, or is the light from these galaxies periodically accelerated by gravitation of intermediary systems? I will let you guess which hypothesis I favour.

Secondly, the mathematics describing the “pioneer anomaly” almost exactly matches the mathematics put forward in my initial post. For those who are unclear on the anomaly, it relates to observed deviations from predicted velocities of pioneer 10 and 11. There are more examples, but these two are the best and most predictable. Both pioneer spacecraft (after which the anomaly was named), traveling in largely different directions away from the earth, are both decelerating faster (and at the same rate) than conventional science predicts. Wikipedia has a short but informative article on this.

 

[Mamluk]

[Moved from the duplicate post]
The velocity of light can be measured very accurately with an inferometer. Google 'inferometer and speed of light' and check it out. The bottom line is that the speed of light that is coming from any object regardless of it speed, the observers speed or the distance from the observer ALWAYS measures the same speed in a vacuum.

The red shift is due to the wave length change (or frequency change if you like) not a speed change.

Certain interferometers are very accurate at measuring the speed of light when that light is generated close by. It is far less trivial to do so for light originating from other galaxies, and much of that is calculated rather then measured. As far as the bottom line goes, I would like your interpretation:

Rays across varying spectra emitted (presumably) at the same time from a black hole in the Markarian 501 galaxy, arrived at different times on earth - approximately 4 minutes across 500 million light years.

Similarly, NASA's Fermi gamma-ray telescope observed that high-energy protons arrived 20 minutes later than certain low-energy protons generated (presumably) at the same time - across a distance of 12 billion light years.

 

[Mamluk]

Mamluk, you seem to be referring to a variable speed of light cosmology in the duplicate thread.

There is a very big difference between the speed of light varying during the history of the universe (VSL theory), and what you proposed above, which seemed to indicate that we should be receiving light at various speeds, depending on how long it has been travelling for.

With VSL theory, the speed of light is a constant at any given time during the history of the universe, but its value has been changing, and was 60 times faster during the inflationary epoch. VSL is an attempt to solve the horizon problem without invoking inflationary cosmology, but it does not by any means imply a static universe. The universe is expanding, and VSL is only any use as an alternative solution for cosmic inflation, which lasted a fraction of a second.

I understand the VSL theory, but I do not have a view on it, nor am I referring to it. The universe may or may not be expanding, but if it is, it is my contention that it is doing so at a far slower rate than 72.5 (km/s)/Mpc.

 

[csmyth3025]

Mamluk,

I'm not well versed in the ability of the astronomical community to measure the speed of light from various sources. I understand that astronomers are capable of isolating the spectra of many distant objects and, thus, determine the spectral shift of those objects.

It seems to me that if the light from a distant object can be isolated for the purpose of determining spectral shift, it should also be possible to measure the velocity of that isolated beam of light. Do you know if this has been attempted (or if it's even possible)?

I've been thinking about the concept of light slowing down with distance as you describe. As I understand it, there is a more complicated relativistic formula for determining large cosmic distances based on the red-shift phenomenon which yields a different result than the simpler Doppler shift relationship attributed to an object's motion away from (or towards) the Earth. Regardless of which formula one uses, your "slowing down" concept seems to have a canceling effect on the observed red-shifts of distant objects. Let me explain:

One may attribute the red shift of a distant object to the "stretching out" of the wavelengths of light due to the general expansion of the Universe during the time the light spent traveling from that distant object to us. If that light also slows down with distance (time traveled) then the wavelengths of that same beam of light would be correspondingly blue-shifted. My reasoning for this is that, as far as I can tell, the individual component frequencies of the light beam remain unchanged but the distance between each "peak" in a given waveform would be compacted due to the fact that the incremental distance the light travels in the time between those peaks is less as the total distance the light travels increases.

Unfortunately, I don't have the math skills to determine quantitatively the effect your "slowing down" formula has on the formula normally used to determine distances on a cosmological scale. I'm hoping that you, or someone else in this forum, may be able to make that calculation. In general it seems to me that your proposal would have the effect of significantly increasing the distances calculated for the most remote objects we've observed.

It's entirely possible that I don't have a clear understanding of the relationship between your "slowing down" formula and the formula commonly used to calculate cosmological distances. If this is so, feel free to correct me.

Chris

 

[origin]

Similarly, NASA's Fermi gamma-ray telescope observed that high-energy protons arrived 20 minutes later than certain low-energy protons generated (presumably) at the same time - across a distance of 12 billion light years.

You mean photons not protons. This press release indicates that the difference in the arrival time between the high and low level photons was 16.5 seconds, not 20 minutes. The article goes on to say that the cause is most likely that the photons were produced in different areas of the burst or at different times.

The article goes on to say a much more speculative idea is that there is a quantum aspect to space that would infact mean that the speed of light would be very slightly different for different energy photons. However even this speculation has nothing to do with your proposal for several reasons:

1. The speed differences are so slight that it is only detectable over billions of light years, so it is nothing like the speed changes you are talking about
2. More importantly, there is no speed change! A photon of a given energy does not change speed, regardless of the distance traveled.
3. This is just a speculation it is not even a hypothesis.

Interesting read though - thanks.

 

[Mamluk]

Similarly, NASA's Fermi gamma-ray telescope observed that high-energy protons arrived 20 minutes later than certain low-energy protons generated (presumably) at the same time - across a distance of 12 billion light years.

You mean photons not protons. This press release indicates that the difference in the arrival time between the high and low level photons was 16.5 seconds, not 20 minutes. The article goes on to say that the cause is most likely that the photons were produced in different areas of the burst or at different times.

The article goes on to say a much more speculative idea is that there is a quantum aspect to space that would infact mean that the speed of light would be very slightly different for different energy photons. However even this speculation has nothing to do with your proposal for several reasons:

1. The speed differences are so slight that it is only detectable over billions of light years, so it is nothing like the speed changes you are talking about
2. More importantly, there is no speed change! A photon of a given energy does not change speed, regardless of the distance traveled.
3. This is just a speculation it is not even a hypothesis.

Interesting read though - thanks.

Hi origin,

I did mean photons and not protons. The article I read http://www.newscientist.com/article/mg20327246.800-13-more-things-magic-results.html did indicate 20 minutes and not 16.5 seconds. Just so you know that I was not trying to mislead. The point was made to indicate that photons emitted from a single source (speculative) could in fact travel at different (slightly) speeds.

1. The arrival times of the different energy level photons is relative to one another and not an indication at what speeds they were traveling at the time of arrival.
2. The photons traveling from the source 12 billion light years away did not travel at an average speed of c. Depending on the refractive indices of the mediums the photons travelled though, the average speed would have been c/n where n is the average refractive index of the mediums at each point of the journey, regardless of the energy of the photon. I suppose the main difference between our views would be here: does the photon regain its velocity of c (assuming a perfect vacuum at a point) after traveling though a non-perfect vacuum medium or not? Did it lose some energy in the medium or not? Depending on the causal effect of point 1, it would seem that certain photons either spent more time in the medium or retained less energy on exiting the medium than others or both.
3. Of course, but hypothesis sounds so much better. If I could just solve the red-shift issue...

 

[csmyth3025]

by csmyth3025 » Wed Sep 09, 2009 12:21 am

...If that light also slows down with distance (time traveled) then the wavelengths of that same beam of light would be correspondingly blue-shifted....

and

by Mamluk » Wed Sep 09, 2009 10:16 am

3. Of course, but hypothesis sounds so much better. If I could just solve the red-shift issue...

Mamluk,

I hope your referring to the red-shift issue I "speculated" about (above). This question still has me stumped.

Chris

 

[origin]

The arrival times of the different energy level photons is relative to one another and not an indication at what speeds they were traveling at the time of arrival.

That is correct, and the differences in the speed of the photons (if there is a difference in speed) cannot possible be detected by any means because it is too small. So at this point the data is simply interesting and it is telling us something about x-ray burst or space itself - but what that is we do not yet know.

You are not implying in the statement above that the incoming speed of light is less than c in a measurable amount are you.
If you believe this to be true then you should get an inferometer and isolate the light from a distant source and collect your Nobel Prize and do the talk show circuit, because that would shake the very foundations of physics.

I suppose the main difference between our views would be here: does the photon regain its velocity of c (assuming a perfect vacuum at a point) after traveling though a non-perfect vacuum medium or not?

Theoretically light should increase in speed when it moves from say water to air or say from a piece of glass to air. Experimental evidence has shown that this is indeed the case. So it is not a matter of ones view, it is simply the way it is.
Did you know that it takes photons that are created near the center of the sun about 30,000 years to make it to the surface (talk about refractive index!)? Even after that the photons are traveling at c as seen by the Michelson–Morley experiments, which is the same speed as photons created by a laser on earth.

At some point you are going to have to accept that your conjecture about the speed of light slowing has been theoretically and experimentally disproven over and over. Scientist have tried every conceivable way to make or find the speed of light anything but c in a vacuum - but to no avail.

Clinging to an idea like this that has been so thoroughly refuted is a waste of your time.

 

[Mamluk]

by csmyth3025 » Wed Sep 09, 2009 12:21 am

...If that light also slows down with distance (time traveled) then the wavelengths of that same beam of light would be correspondingly blue-shifted....

and

by Mamluk » Wed Sep 09, 2009 10:16 am

3. Of course, but hypothesis sounds so much better. If I could just solve the red-shift issue...

Mamluk,

I hope your referring to the red-shift issue I "speculated" about (above). This question still has me stumped.

Chris

Hi Chris,

There are several possible models that can explain the red-shifting of distant galaxies. Sadly, at this stage, only one model can do so without blurring our view of the distant galaxies, while supporting time-dilation and the CMB. Guess we are stuck with a constant speed of light, an expanding universe, dark matter and dark energy...

 

[origin]

There are several possible models that can explain the red-shifting of distant galaxies. Sadly, at this stage, only one model can do so without blurring our view of the distant galaxies, while supporting time-dilation and the CMB. Guess we are stuck with a constant speed of light, an expanding universe, dark matter and dark energy...

Good for you mamluk! It appears that you looked at the available information and deduce that the idea of slowing light is not a viable option. That is what scientist do, they postulate ideas and see if it makes sense with the available data. Everybody comes up with wrong conclusions sometimes, there is no shame or harm in that - the problem is when people cling to the ideas in the face of data showing them wrong. You can see that in several individuals on this very forum. They defend their conjectures even with all evidence to the contrary. Invariable these people start talking about conspiracies and the establishment being against them.

As far as 'stuck' with dark matter and dark energy - no one has any clear idea what these 2 things even are! Observations and data has shown that there appears to be more gravity than expected in the galaxies, a lot more, what is the source of the gravity - dunno, lets call it dark matter until we know what it is. Same with dark energy - the expansion of the universe is acclerating, why - dunno, lets call it dark energy until we can figure out what in the heck is going on.

 

[csmyth3025]

At the risk of sounding like I'm beating a dead horse, are there viable cosmological models which incorporate a speed of light which varies in some relation to the the expansion of the universe?

Chris

 

[origin]

At the risk of sounding like I'm beating a dead horse, are there viable cosmological models which incorporate a speed of light which varies in some relation to the the expansion of the universe?

Chris

There are no viable options that I know of.

 

[csmyth3025]

On the subject of the speed of light - why does light slow down in air or water or glass? Is it repeatedly absorbed and re-emitted by the matter or is there some other effect?

Chris

 

[Agnostic_Jesus]

Re: Alan Guth vs Joao Maguelijo

I've heard all the theories on inflation and I come to the same conclusion every time.
If "space" expanded, then what is space? Is it an invisible 3-dimensional graph necessary for matter to come into existence?
If space never expanded to accomodate matter, then would all the matter in the universe have continued to stay in its state of infinite density and subatomic scale? These theories seem to say that in the time before time space acted like a cocoon, shrouding all the matter in the universe, squeezing and containing it all into a subatomic point, or singularity. Some event occured that liberated the stranglehold and space expanded.
But not one theory has ever mentioned or even attempted to explain what space is? Energy? Matter? Something else entirely?
If it can contain a universe into an infinite point, surely it merits some explanation?
What was on the other side of space?

 

[ramparts]

Re: Alan Guth vs Joao Maguelijo

I've heard all the theories on inflation and I come to the same conclusion every time.
If "space" expanded, then what is space? Is it an invisible 3-dimensional graph necessary for matter to come into existence?
If space never expanded to accomodate matter, then would all the matter in the universe have continued to stay in its state of infinite density and subatomic scale? These theories seem to say that in the time before time space acted like a cocoon, shrouding all the matter in the universe, squeezing and containing it all into a subatomic point, or singularity. Some event occured that liberated the stranglehold and space expanded.
But not one theory has ever mentioned or even attempted to explain what space is? Energy? Matter? Something else entirely?
If it can contain a universe into an infinite point, surely it merits some explanation?
What was on the other side of space?

Actually, no theory talks about "the time before time" - because that concept doesn't make sense We have no idea what happened "before" the Big Bang or what caused it, though some theories have their predictions about it, but I'm not aware of many (or any) theories where spacetime somehow "squeezed" matter in before being "liberated".

As for the question of what spacetime is, that's one of those questions for which there will probably never be a completely satisfactory answer. No, not energy or matter, but a background on which things act, and which can change and be dynamic. Whether it's "made" of something... well, that remains to be seen

 

[mortisthewise]

Re: Alan Guth vs Joao Maguelijo

Spacetime is one single fabric that covers the entirety of our universe. Its inherent properties define the behavior of all mass and energy within it. It is pointless to speculate about what lies 'beyond' or 'on the other side of space'. Anything 'outside' of our universe would not necessarily have the same dimensions, if any, nor have the same physical properties. Comparison are meaningless without a common frame of reference.

In spacetime, the physical dimensions are inseparable from time...they are one in the same, although we perceive them as being independent. Extra dimensions that we cannot sense may exist. The behavior of spacetime during the big bang (apparently expanding faster than the speed of light) seems odd in today's universe. But under Grand Unified Force conditions, the forces of the Universe were not separate, competitive forces as they are today, but were instead one in the same. Evidently when our spacetime was subject to such conditions, it was able to expand at a rate faster than the current speed of light. Every fundamental force of the universe...magnetism, for example....did not work the same as it does today, as the grand unified force is gravity+magnetism+strong force, etc.

Consider a superconductor. At room temperature, it has normal electrical properties...in some cases huge resistance. But under the right conditions, something magical happens and all resistance disappears entirely. Perhaps spacetime is in the role of the superconductor; under the right circumstances spacetimes can have properties it does not have under any other circumstances.

 

[pjay]

Spacetime is one single fabric

That's at least what general relativity would suggest, but general relativity is a classical theory and will certainly be replaced at some point by something more in line with quantum mechanics. One way to go is string theory, which mortisthewise mentiones in passing with his reference to extra dimensions. Another interesting contender is loop quantum mechanics which could potentially solve the singularity problem. It suggests that spacetime itself is quantified with planck length and planck time being the smallest quanta. If you accept this then you can explain inflation quite well and you get rid of singularities. Instead the big bang is only a passing stage that never reaches the point of infinite density, pressure, temperature etc.. called singularity. Spacetime never stops existing and you can talk about what the universe was like before the big bang. WOW!