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Quote from: Ethos_And as well, the term Past has no meaning without the memory of it which occurs in the Present. I disagree. To a small extent the past can be deduced from causality as well as memory.
And as well, the term Past has no meaning without the memory of it which occurs in the Present.
Another conundrum lies in the interaction between light and either the medium it is traveling through or a gravitational field acting on the photon. The photon now no longer travels 1 Planck length in 1 Planck time.
Quote from: jeffreyH on 16/08/2014 12:24:54Another conundrum lies in the interaction between light and either the medium it is traveling through or a gravitational field acting on the photon. The photon now no longer travels 1 Planck length in 1 Planck time. From my understanding, the photon always travels at 1 Planck length in 1 Planck time. The reason it appears to slow down is, when in any medium other than the vacuum, the photon will be absorbed and then subsequently readmitted. This interruption in the photon's path has the appearance of slowing it down. But in truth, the speed of the photon from one absorption to the next is still c. Between each interruption the photon still travels at light speed, 1 Planck length in 1 Planck time.
So,..........what is time according to Einstein?Quote from Albert Einstein: "The distinction between the past, present, and future is only a stubbornly persistent illusion."
Quote from: petm1Space and time, opposites yet the same.Woa! Where did you get that notion from? It's certainly not true. While in some respects space and time are treated on the same footing in relativity mathematical, it's certainly not true that their anything alike physically, that's for sure. Space is what you measure with a rod. Time is what you measure with a clock. You can go back in space but you can't go back in time. You can rotate one spatial axis (i.e. a rod) into another spatial axis but you can't rotate a rod into a clock.Let me quote something Einstein said about this. From A Brief Outline of the Development of the Theory of Relativity by Albert Einstein, Nature, Feb. 17, 1921. page 783QuoteFrom this it follows that, in respect to it's role in the equations of physics, though not with regard to its physical significance, time is equal to space coordinates (apart from the relations of reality).Quote from: petm1Photon is unchanging in time..That too is also untrue. A photon moves through space and its phase changes with time. You're thinking about transforming into a photons frame of reference and making measurements there with a clock and comparing it to the photon's frequency, etc. However since it's impossible to do that you can't even speak of it. Therefore the only time that you can speak of regarding a photon is coordinate time. Just because you can't speak of a photons proper time it doesn't mean that it's unchanging. You'd never be able to step into a photons frame of reference to verify it and that's not science.
Space and time, opposites yet the same.
From this it follows that, in respect to it's role in the equations of physics, though not with regard to its physical significance, time is equal to space coordinates (apart from the relations of reality).
Photon is unchanging in time..
..."The non-divisibility of the four-dimensional continuum of events does not at all, however, involve the equivalence of the space coordinates with the time coordinate"...The author of SR didn't believe or promote the idea of an objective time. In contrast, he developed the idea of clock time or time measurement as being motion dependent...
Depends on definitions phyti. Time is locally unchanging for each observer in my thoughts, you do not gain more life by sitting on a event horizon for example, observing a universe die. That's why we all live and die, doesn't matter where or how fast. The other comparisons is between frames of reference, and there NIST has proven time dilations to exist at centimeters. If you now want to expand on that line of wondering you might ask yourself where it all ends? Is there a discrete 'point' representing a equivalent local arrow, as a 'property' more or less.=
Time is a scalar, and has no direction, so there is no arrow of time.
Quote from: phyti39Time is a scalar, and has no direction, so there is no arrow of time.I recommend that if you wish to delve into the physics of special relativity that you learn the mathematical terms correctly. This won't be possible unless you pick up a good textbook on special relativity...
Reflection and refraction follow definite paths.... This is the concept I have a problem with. Application of the uncertainty principle should mean that this path deviates and yet it doesn't.
Quote from: phyti39Time is a scalar, and has no direction, so there is no arrow of time.I recommend that if you wish to delve into the physics of special relativity that you learn the mathematical terms correctly. This won't be possible unless you pick up a good textbook on special relativity that explains it using tensors. Tensor analysis is the language of relativity, and hence the math that you should learn. May I inquire as to the level of math that you're familiar with?The term scalar as you used it comes from elementary school math and science textbooks. It that sense it means a number, real or complex. In tensor analysis it means something else, i.e. A scalar is a tensor of rank zero. This means that it's a number which remains unchanged upon a valid change of coordinates. For example; if you were working in special relativity and using Cartesian coordinates for your spatial coordinates then the coordinate transformation from one inertial frame to another, which is in standard configuration with the original one, is referred to as a Lorentz Transformation. So a Lorentz scalar is a number which remains invariant (i.e. unchanged) upon a Lorentz transformation.I mention it so that you learn this early on. If you continue to discuss relativity with learned physicists then you'll have to learn the jargon.
Time as a derived number, distance/speed, is a variable.
The Lorentz tranformation of t results in a different value for t', for relative motion.
You can do SR using algebra!
I'm not here to impress anyone, so my level of math is irrelevant.
All in all. TNS is probably the best place i know, although I've seen some very close to it. But, we still have that glimmer of humility hiding behind our convictions, and that is in my mind, what science is about, not bullying, talking.=And that goes especially for you moderating.Keep on doing the work you do.And now I will define 'c' as something similar to a turtle, I'm positive you will agree?