and can be delayed up to 500 nanoseconds in a slow light medium.
That's c plus 3 mph...too late to edit
isn't the light traveling at c (plus) 3 miles per hour?
Time travel was never going to be possible, because Time itself does not exist as a physical reality.
It is just a human invented measurement.
The MEASUREMENT of time is a human construct, not time itself. Explain gravity and relative velocity time dilation if time doesn't exist.
.. only because photons are absorbed and re-emitted by electrons that make up the medium ..- Noumenon
Time travel was never going to be possible, because Time itself does not exist as a physical reality.
It is just a human invented measurement.
This is false. Time is a property of entropy, which can be quantified using phase space. Our perception of time is a construct, but this is simply stating a truism.
I'd like to "suppose" something (on topic, I hope).
I've heard that high velocity travelers will age less than their peers. If this is true, would return voyagers only perceive themselves younger or would they actually be younger than their peers?
Please indulge one more.
If traveling to a star four light years distant at 99.9% light speed, how long would the voyage be perceived to take by the traveler?
(not a physicist - real questions to me).
There seems to be a lot of mixup between light and photons. Also, 'empty space' doesn't exist; there is always at least gravity and other forces as long as there is a single speck of energy in the universe. By this definition (mostly-empty) a photon ALWAYS travels through empty space, even though various forces may deflect it. When it hits something, most likely an electron, it's no longer in empty space. It then ceases to exist, its energy absorbed by the electron. Which then promptly reemits (refracts) it in the form of a DIFFERENT photon. This slows down light propagation, but it doesn't slow down the photon. A secondary effect, of photons traveling in strong force fields, may have a slowing effect as well but that's basically 'empty space'.
I've heard that high velocity travelers will age less than their peers. If this is true, would return voyagers only perceive themselves younger or would they actually be younger than their peers?
Then there is this: "Scientists break speed of light"
http://www.cbc.ca...720.html
There seems to be a lot of mixup between light and photons. Also, 'empty space' doesn't exist; there is always at least gravity and other forces as long as there is a single speck of energy in the universe. By this definition (mostly-empty) a photon ALWAYS travels through empty space, even though various forces may deflect it. When it hits something, most likely an electron, it's no longer in empty space. It then ceases to exist, its energy absorbed by the electron. Which then promptly reemits (refracts) it in the form of a DIFFERENT photon. This slows down light propagation, but it doesn't slow down the photon. A secondary effect, of photons traveling in strong force fields, may have a slowing effect as well but that's basically 'empty space'.
high speed travelers experience time at a "slower" frame rate than relatively slower travelers.
So they would only be "younger" after a period of time passes for the two of them.
the high speed traveler will measure one minute passing by, and the slow traveler would measure two minutes going by
If the two could then meet again and compare clocks, it would seem that the high speed traveler is "younger"
Time does not exist. There are only intervals between events. Time as we use it is only artifical measurement of these intervals.
One can also say that it is the twin that stays on earth or on the at-rest spaceship who is doing the traveling and therefore not ageing
Light's propagation through space. Light travels space as a projectile like a rifle bullet
Speed of light is NOT constant. It has a maximum velocity (c), the known maximum velocity of any mass.
high speed travelers experience time at a "slower" frame rate than relatively slower travelers.
No, they experience time just like any other person in the universe. They're not moving in slow motion or fast motion - time passes for them as normal.
So they would only be "younger" after a period of time passes for the two of them.
But only if they meet up again.
the high speed traveler will measure one minute passing by, and the slow traveler would measure two minutes going by
No, they will both measure 1 s/s in their own frames of reference.
If the two could then meet again and compare clocks, it would seem that the high speed traveler is "younger"
Not only seem, but he will be younger. The effect is only apparent when clocks (people) are compared in the original (earth) frame of reference. You can only say time is going slower or faster relative to different frames of reference, not your own.
Deesky: you are being unnecessarily picky about laymen explanations...
Your comment is correct but does not apply.
Um, that is the point of this discussion.
No, they will both measure 1 s/s in their own frames of reference.
Inaccurate. This is in contradiction with your earlier assertion that one person really would have aged less than another. Or your later statement that clocks when compared would be different.
If your going to be that picky, you shouldn't then make ambiguous statements that may imply the person became younger as if going backward in time.
Other than that this is just rewording my statement.
"Explain gravity..." - aroc91
I'll pass. The best I can do is describe gravity's observable effects.
The outcomes of anti-hydrogen (antimatter) experiments will add to the descriptions of the effects of gravity. Just as the double slit experiments added descriptions to the effects of the wave nature of matter.
Or as KBK eloquently commented: Framesworks of analysis.
Any thoughts?
Are you joking,No.
Noumenon
Jul 24, 2011