The 'Controversial' Speed of Light-Phenomenon

Originally posted by TN1

As for the speed of light, indeed it is always constant in the vacuum
(300,000km/s) but what about in a long period of time?? is it going to have the same value as it has today?? I leave this to you.

TN1

OK getting over the obvious mistakes you made, I think English is not your first language, so a little grace is granted...........

I doubt very much that the speed of light as measured in a vacuum has always been the same, I suggest that as the universe expands, the speed of light will decrease due to a relative increase in the amount of energy expended in the standard forces that we are aware of, this in turn due to the expansion of dimensions beyong what we can see that these forces are effected by.

This will lead to some interesting events in the future, ie, as the speed of light slows, and taking into account the increasing rate that the universe is expanding, eventually the relative speed of objects in the universe to the "oh so forbidden" but blatenty obvious ether, will become such that all time will slow and therefore we will eventually see an ever slowing universe..........

but that is not the case, we see an ever increasing universe, so what is going wrong??????

I think I will think about this tomorrow and come back with a better explanation tbh

just ignore the above, sorry seemed like a good idea at the time, but as usual the whole "time light universe" thing has complicated things :/


edit - school boy error, as time slows we will see an exponentially increasing universe, ie, as we hit the speed of light, time for us as an observer will stop and therefore the whole time period for the universe will pass us by in but a moment....actually thinking about it the slowing of the speed of light could very well be the reason for universal inflation. /me goes to ponder



[edit on 11-7-2005 by Strodyn]

[edit on 11-7-2005 by Strodyn]

It would be reasonable to assume that ala big bang, the force expelled would in my opinion, increase the speed of light to greater than the norm (it would be carried along with the sub-atomic particles, and light is a particle as well as a wave) , over time and distance (speed) would stabilize to its natural state. Doppler shift also tends to refute a constant, as does the medium through which light passes. Maxwell's theory of the em spectrum encompasses all of the known shift ( to the known of his day) to which we are discovering new on both ends. The visible light to which we are discussing would therefore be a constant within that "visible" spectrum, a very narrow bandwidth within the entire (known) spectrum.

Now my question is one that I have always had (and disagreed with my educators on) is that the speed of light is in fact a constant (hence my assertion above ala big bang) I have always felt that if you were in a marginally sub-light speed vehicle and turned on your headlights, that you would in fact have light in front of you and yet I had always been told that nothing could go FTL, not even light itself. (Again, it is the visible aspect to which we are discussing) If you were going 1 mps sub-light speed and turned on your lights, the vehicles lights are already going the same speed you are (marginally sub-light) and the constant velocity of light wouldn't change, it would remain 186k mps but would be invisible to the bystander who is looking at it from a standstill. It all depends on whether or not you were inside the vehicle (which your headlights would regard as a standstill) or as an observer from a fixed point.
Having said that, it should be theoretically possible to increase the speed of light to that elusive FTL threshold by manipulation. As quoted in that experiment where light was slowed , light can be manipulated on the one end of the scale, why not the other? I can recall when mach1 was a threshold. Perhaps FTL would transform light to another form, (invisible to us) but would still have the charcateristics of visible light in the medium in which it was present. Technically, it wouldn't be light (to us) but is still a part of the em spectrum (gamma?)... and would still be visible light to someone within that medium. Light can be refracted, focused, amplified, dissipated, reflected, all depending on the medium through which it flows. It should be possible to go FTL.
To break that FTL barrier is like trying to describe the color red to someone who has been blind from birth. ... doesn't mean it ain't so.
Last point, and forgive my verbosity here... ever seen a dolphin riding a bow wave? IMHO, if that pressure from a light wave could ever be manipulated, this is where we will find the key to FTL.
*scratching head, shaking it*

Originally posted by keybored
It would be reasonable to assume that ala big bang, the force expelled would in my opinion, increase the speed of light to greater than the norm (it would be carried along with the sub-atomic particles, and light is a particle as well as a wave) , over time and distance (speed) would stabilize to its natural state.

While this may seem to make sense or "feel" right, it is not. The universe's expansion is not "carrying along...the subatomic particles." The expansion means more space for a light wave to traverse as it traverses this space.
Light in a vacuum is not traveling in a medium. If it were, and you manipulated this medium, then you could possibly have a point. As it is though, the expansion of the universe only tends to increase the wavelength of the light.

Originally posted by keybored Doppler shift also tends to refute a constant, as does the medium through which light passes.

Neither refutes a constant speed of light in any way, shape or form. References please?

Originally posted by keybored I have always felt that if you were in a marginally sub-light speed vehicle and turned on your headlights, that you would in fact have light in front of you and yet I had always been told that nothing could go FTL, not even light itself. (Again, it is the visible aspect to which we are discussing) If you were going 1 mps sub-light speed and turned on your lights, the vehicles lights are already going the same speed you are (marginally sub-light) and the constant velocity of light wouldn't change, it would remain 186k mps but would be invisible to the bystander who is looking at it from a standstill. It all depends on whether or not you were inside the vehicle (which your headlights would regard as a standstill) or as an observer from a fixed point.

You have answered your own question in this paragraph. The fact that the speed of light is constant means that one may never measure light speed above or below the known constant speed in the particular medium. Light travels fastest in a vacuum, so this is the "speed of light" we always talk about. In your above example, the stationary observer would measure the speed of your headlight beam at c. You would also measure the speed of your headlight beam at c. The latter may not seem to be so strange, but the former implies, exactly as you said, that since your ship is travelling at c-1, then the light beam is actually moving at a speed of 1 to the stationary observer and at a speed of c relative to you. How is this possible? Google time dilation and relativistic length constriction to find out.

Originally posted by keyboredHaving said that, it should be theoretically possible to increase the speed of light to that elusive FTL threshold by manipulation. As quoted in that experiment where light was slowed , light can be manipulated on the one end of the scale, why not the other?

It may turn out to be theoretically possible to increase the speed of some particles (maybe even photons) to above c. There are proposed particles called tachyons that only exist at speeds above c. Any particle that is to travel at a speed of c or greater must absolutely be massless, as is a photon (tachyon too.)

Originally posted by keybored ever seen a dolphin riding a bow wave? IMHO, if that pressure from a light wave could ever be manipulated, this is where we will find the key to FTL.
*scratching head, shaking it*

You need a little more head scratching. The dolphin in your example cannot be accelerated faster than the wave he is riding by manipulating the wave itself. It is only by combining gravity with the wave force that speeds greater than the wave can be achieved. No force at a distance acts at speeds faster than light, whereas the gravitational force surfers (and your dolphin) use acts at much higher speeds (actually lightspeed) than the speed of a bow wave. More force than just the "wave force" must be applied to accelerate someone to a speed greater than the wave he is riding.

Harte

Speed of light has been exceeded many time in wave guides hear on Earth. Google it. Physicists now use the statement that "information can not exceed the speed of light"....

Quantum entanglement is quite nifty too but is there something actually traveling faster than light - ?????

My apologies, you are right, I didn't type that out very well. I'll try to take it point byt point...
" The universe's expansion is not "carrying along...the subatomic particles."

my typo, should have been carried, along with

"Light in a vacuum is not traveling in a medium."

A vaccum is a medium (IMHO) Further, this "vacuum" as we know it isn't completely void. North is North even in space so there is a magnetism, There is cosmic radiation, temperature, particles being blown by a solar wind so there is also a wind just to name a few things this "vacuum" contains. Our perception (mine particularly lol) seems flawed when you look at things from a different perspective. Take the air we breathe, it is a fluid. lightning is liquid electricity, warm feels hot if you come in from the cold, cool feels cold if you come in from the hot. Since our vision is limited to visible light, all we see is the illumination and yet I particulaly like that doo-dad that looks like a light bulb with vanes inside of it. The vanes are black on one side and when light hits it, the vanes spin. Light can be made to do work as well as being tapped for electricity (photo-voltaic cells) besides giving our eyes (which have their own limitations) some use.

" As it is though, the expansion of the universe only tends to increase the wavelength of the light."

On this I wonder, theorists have postulated that the big bang is only one side of it, the other being the big crunch whcih ultimately leads to another big bang and so on. Having said that, even though space seems like a nothingness to us, it must be confined otherwise how would that back pressure build up to the crunch?
I'm not entirely sure of wavelength, I would think it would get diffused (dissipated) over distance, although perhaps this IS the wavelength and I just didn't know what to call it. I do know that going through prizms it gets broken into its varying wavelengths, going through a Ruby creates a laser, going through water it gets diffracted. What I don't know is what light becomes once it goes FTL (I still think its possible though)



quote: Originally posted by keybored Doppler shift also tends to refute a constant, as does the medium through which light passes.
Neither refutes a constant speed of light in any way, shape or form. References please?

Reference me on this one. I would think that as light comes towards you it is one form, going from you its another hence the Doppler shift...Like the way sound has a pitch change.

You have answered your own question in this paragraph. The fact that the speed of light is constant means that one may never measure light speed above or below the known constant speed in the particular medium. Light travels fastest in a vacuum, so this is the "speed of light" we always talk about. In your above example, the stationary observer would measure the speed of your headlight beam at c. You would also measure the speed of your headlight beam at c. The latter may not seem to be so strange, but the former implies, exactly as you said, that since your ship is travelling at c-1, then the light beam is actually moving at a speed of 1 to the stationary observer and at a speed of c relative to you. How is this possible? Google time dilation and relativistic length constriction to find out.

Technically this is apples and oranges. FTL light wouldn't be visible to the bystander so it is probably incorrect of me to refer to it as light once FTL had been attained. Lacking a better word for it I guess it could be called phased.

quote: Originally posted by keyboredHaving said that, it should be theoretically possible to increase the speed of light to that elusive FTL threshold by manipulation. As quoted in that experiment where light was slowed , light can be manipulated on the one end of the scale, why not the other?

It may turn out to be theoretically possible to increase the speed of some particles (maybe even photons) to above c. There are proposed particles called tachyons that only exist at speeds above c. Any particle that is to travel at a speed of c or greater must absolutely be massless, as is a photon (tachyon too.)

If the light remained light from the vehicle, it is still light even though it has "phased" If this is then a tachyon (to the bystander) once it makes that shift, again it would all be in the perception wouldn't it?
As to being massless, mass (or for lack of a better term in the case of light, the volume) of light would increase in length but decrease in intensity since as it got stretched out it would diffuse.


You need a little more head scratching. The dolphin in your example cannot be accelerated faster than the wave he is riding by manipulating the wave itself. It is only by combining gravity with the wave force that speeds greater than the wave can be achieved. No force at a distance acts at speeds faster than light, whereas the gravitational force surfers (and your dolphin) use acts at much higher speeds (actually lightspeed) than the speed of a bow wave. More force than just the "wave force" must be applied to accelerate someone to a speed greater than the wave he is riding.

Ahh but, the analogy of the dolphin was to demonstrate that the dolphin rides the bow wave effortlessly. The dolphin still has its own steam to draw upon and often does jump out ahead of the bow wave.
As to the gravity combining with the waveforce, I don't follow you here. I would think gravity would be way too slow to impact a light wave in any way other than negatively?

Thank you for taking the time to reply to my assertions. I should point out that I have no formal training in any of these fields and the hypothesis or conclusions I draw stem from me alone. I am still learning.
Thanks again for the google tip, I do intend to go over it (as soon as I get off these boards lol) and am sure to learn from it. My thirst for knowledge is unquenchable.

You know, since we are talking about light(visible) I guess another aspect to touch upon are optics. Have you ever noticed how that digital camera manages to "see" better than we do? Our eyes are so inferior to our technology, don't you think that possibly our technolgy will one day make that leap to FTL? I do. It starts with the math. If we can calculate it, we can figure it out. IMHO of course.

Thanks for your replies very much.

Indeed as a friend explained above, general relativity predicts the existence of particles called tachyons (from the Greek word tachy, which means fast).

Tachyons may exceed the speed of light, but the physics behind this (theoretical) phenomenon is not yet understood.

Another important part of our discussion is whether we can detect absolute vacuum!!

According to our understanding of physics absolute vacuum cannot be detected, which means that light interacts with matter in some degree.

Thanks again,

TN!

I forgot to comment on the idea of light travelling in vacuum. Actually it doesn't travel in absolute vacuum.

As for the redshift is absolutely true. All galaxies tend to mone away from each other due to the expansion of the universe.

I feel that there is also something else going on that we haven't understood yet, those who know about tensors will probably know what I am talking about.

TN1

What about neutrinos?

From my understanding they are theoretically faster than light. In fact one bit of theory I saw regarding them was that someday we can use neutrinos to see into the past if we can move fast enough away from the earth with recording equipment, because neutrinos pass through almost everyhing (supposedly, we havent reached the level of refinement to know what particles make up a neutrino)

There is a neutrino observatory in Sudbury Ontario Canada.
As to the possibility of travelling backwards in time, I believe it is possible although not with our level of understanding of the mechanisms involved. The reason I believe its possible? The Book of Revelations was written from our future, given to us in the past, and lived in the present.

Kind of gives a whole new meaning on the term "being saved" if you think about it. The dead in Christ shall rise again could mean if you give your life willingly in Christ's name taking that leap of faith, backward time travel could pick you up before you died. (although this is just a whimsical depiction of a possibility not a probability since it would take a good number of trips to reclaim all who are written in the book of life... but only God knows the answer to that one)

Originally posted by keybored
There is a neutrino observatory in Sudbury Ontario Canada.
As to the possibility of travelling backwards in time, I believe it is possible although not with our level of understanding of the mechanisms involved. The reason I believe its possible? The Book of Revelations was written from our future, given to us in the past, and lived in the present.

Kind of gives a whole new meaning on the term "being saved" if you think about it. The dead in Christ shall rise again could mean if you give your life willingly in Christ's name taking that leap of faith, backward time travel could pick you up before you died. (although this is just a whimsical depiction of a possibility not a probability since it would take a good number of trips to reclaim all who are written in the book of life... but only God knows the answer to that one)

Thats a stretch, seeing as the bible isnt even that original considering the sources they drew on for the stories contained in it. But lets not derail this thread.

Originally posted by UofCinLA
Speed of light has been exceeded many time in wave guides hear on Earth. Google it. Physicists now use the statement that "information can not exceed the speed of light"....

No it hasn't. The speed of light in matter can be slowed down and can be exceeded by particles (this results in Cerenkov radiation) or the group velocity of a number of photons of different wavelengths - in a wave guide for example - can be larger than the speed of light, but the latter is just a mathematical thingy. The actual photons themselves still move at their characteristic speed, equal to or lower than the speed of light in vacuum. Similarly, if you rotate a beam of light on a wall far enough away, the lightspot can move an unlimited number of times faster than the speed of light. That's just a mathematical expression for the speed of the spot, the actual photons in the lightbeam all travel at the speed of light and the spot itself is not a physical thing.

[edit on 22-7-2005 by Simon666]