Your right about this. I noticed the error as going to bed and did not correct it. The end of the rope would move away from me even if he did not. (I.e. he accelerated “just right” for him to remain stationary for me by my measures as you suggest in this post.) And if he is coming closer by my meter sticks, as you suggested in earlier post, then the end of the rope can remain at my side....2 - Why would you think only space contracted and not physical dimension of mass which occupies space? The rope should also contract and seem to stay along side.
Your words are too ambiguous to be clear: If the two blue "you"s refer to the one who accelerates then this is false as he does move wrt to me as he measures it. Again the red words "never move" are only true wrt me in my frame measured by my meter sticks. I.e. the distance to the rocket from me is remaining constant as I measusre it But NOT as he measures it. You need to tell more clearly what you mean. (But for both of us, the end of the trailing rope is moving away from me. For me true as the space between each of the 400 knots is growing shorter. For him true as he is moving away from me.)...Of more interest is the basic physics consequences. i.e. - If you accelerate away just right you never move. You have Force from F = ma. You are consuming fuel (energy) up the gazoo but Wk = F * d and you have no "d" hence no work achieved for the F produced from the consumption of energy. If energy cannot be created or destroyed where did it go?
Tell me where the logic is wrong.
Your right about this. I noticed the error as going to bed and did not correct it. The end of the rope would move away from me even if he did not. (I.e. he accelerated “just right” for him to remain stationary for me by my measures as you suggest in this post.) And if he is coming closer by my meter sticks, as you suggested in earlier post, then the end of the rope can remain at my side. Your words are too ambiguous to be clear: If the two blue "you"s refer to the one who accelerates then this is false as he does move wrt to me as he measures it. Again the red words "never move" are only true wrt me in my frame measured by my meter sticks. I.e. the distance to the rocket from me is remaining constant as I measusre it But NOT as he measures it. You need to tell more clearly what you mean. (But for both of us, the end of the trailing rope is moving away from me. For me true as the space between each of the 400 knots is growing shorter. For him true as he is moving away from me.)
On can consider that the rocket is constantly joining a new inertial frames for zero time. In each of these new frames his higher velocity contracts the growing separation distance, measured in his frame, more for me to make his separation from me by my measure constant,while by his meter sticks he is leaving me far behind.* Since he is stationary in terms of my meter sticks, Newton's third law applies. It states that a stationary object has zero net force on it. (Both F & d in the work equation, are constants for me.) So he is not doing any work in my frame. Yes, I see his rocket burning fuel but it is not doing any more work than is being done on the stationary logs in a bonfire as they oxidize.
Energy is conserved in my frame by chemical energy becoming heat - just like a bonfire.
Likewise if I consider the KE in a set of other frames, each of which is moving faster wrt my bon fire then that bon fire is gaining KE in those frames. KE is relative to the frame. There is always some frame in which the KE of the bullet I just fired is zero - that does not mean that energy is not conserved.
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*Again your lack of understand is due to your lack of precision with a words only description.
If, I were as ambiguous / vague as you are, I can say both:
(1) He does not move. (As you did.)
(2) He is moving very rapidly.
(1) is true if I measure with my meter sticks the distance to him. (Assuming with you he is accelerating ”just right.”)
(2) is true if he measures with his meter sticks the distance to me.
For example, from his POV, the 400 knots in the rope he is trailing are neither changing their separations nor is the end staying over my head as it was when he first let lose his rocket blast. The distance back to me, measured by his meter sticks is increasing. I.e. that distance is more than the CONSTANT TO HIM length of the trailing rope. The gap between me and the end of the trailing rope is increasing. – End of rope is moving away from me for both of us.
There are no mysteries here - only ambiguous use of words in your post make it seem so.
SRT does not state that. He only dilates time and contracts space AS HE MEASURES IT. For all others the distance to Alpha Centaurs remains unchanged etc....The idea that an observer, by simply moving, can contract space-time in the entire universe, ...
SRT does not state that. He only dilates time and contracts space AS HE MEASURES IT. For all others the distance to Alpha Centaurs remains unchanged etc.
I don't use the words "perception" "sees" "observes" etc. if I can avoid doing so as that gets confused with simultaneity and delay of light questions, but basically yes, if correctly measured (and that is not easy) the rest of the universe contracts and time dilates only for him.Billy T, Are you saying that actual space-time does not physically change, only the moving observer's perception of it does?
I don't use the words "perception" "sees" "observes" etc. if I can avoid doing so as that gets confused with simultaneity and delay of light questions, but basically yes, if correctly measured (and that is not easy) the rest of the universe contracts and time dilates only for him.
I do not understand how one could possibly think as QQ does that an acceleration, which was over 150 years ago, can leave a permanent change in the energy levels of a cesium atom so that the frequency used in a cesium atomic clock, moving wrt me is different than my cesium based clock. That even violates the idea that physic is the same in all inertial frames!
Because it is not an ilusion. It is a real effect on him.... why modify all the physics equations to adjust for that change, instead of just disregarding what the observer sees as an illusion?
It does not slow down. In vacuum light always travel at the same speed, C. What is does is lose energy as it climbs up out of the gravitional well so it becomes "red shifted."...I simply believe that for a clock that is moving through a gravitational field, light slows down. Therefore, the reactions in the clock slow down, causing the clock to tick slower. No need for time dilation or length contraction.
PS James told you the truth. Space time does change, it is not an illusion of change, for the moving guy.
It does not slow down. In vacuum light always travel at the same spped, C. What is does is lose energy as it climbs up out of the gravitional well so it becomes "red shifted."
MacM's (and QQ's) basic tactic seems to be to put up some (usually non-sensical, but defaulting to false in the rare case of the blind chicken) fabricated distortion of what fundamental relativity theory is or implies. Then - with the usual crackpot hubris and almost complete ignorance of (or worse, indifference to) the supreme arrogance they demonstrate by their implying idiocy on the part of thousands of very, very, very smart people who've studied these theories in depth for a century - when nobody rushes to defend their obvious strawmen, to claim that failure to do so demonstrates the failure of the theory.
Such threads do not belong here. The time for rational response is long past, and only ridicule is left - even the temperate BillyT and CptBork have exhausted their otherwise seemingly limitless patience.
So I say: Begone! Away to the Cesspool with you, foul thread, to corrupt this forum nomore!
Because one measure distance with meter sticks that are not moving wrt one'self I.e. his co-moving meter sticks are not any shorter for him, but the separation for Earth to Alpha Centarus is less, contracted FOR HIM ONLY so it takes less of his still normal meter stick laid end to end to measure that distance. Perhaps 1234567689 of the meter sticks will reach between and I agree on that number as each of them is moving wrt to me and only a few cm long compared to my stationary meter sitcks.Billy T, Please explain to me how an observer can change another object (space-time) at a long distance without using any energy and doing it so that no one witnesses the change but him?
For years an "either" was postulated to be the answer. It has stange properties, no mass, makes no gravity, is never seen, does not remove any energy as the Earth moves thru it to orbit the sun. It rapidly passes thur inch thick steel walls of a vaccum tube, faster than the air can be pumped out, etc. but if light was a wave in the either, then sort of a Doppler effect should occur* as the earth is moving the oppsite way from any star every 6 months and the direct the light seems to coming from changes like when you running thru rain drops changes their approach angle (see more under "stellar aberation") etc. Many tests all failed to show any effect of the postulated either.What if light only travels at c relative to the gravitational field {what is it} moving through?
Maxwell's equations give the speed of light by meauring only two electric and magnetic probertis of the vacuum. This too shows that nothing is required to be the "medium" in which light propagates. Sound waves need a medium. do not progate in vacuum, but light can and does - The sun is shining now for me - that is also proof.
The correct answer requires you know some tensor math and GR theory, but I would somewhat incorrectly answer: Gravity "warps" space.Billy T,
What if light doesn't have a medium or aether, but is pushed by gravitational fields?
Physicists know relativity is not an 'ultimate theory', that it's almost certain something will come along to replace it but that doesn't automatically make you right in your particular criticisms. Your example of accelerating giving length contraction giving shorter distances isn't a problem, you might not like it because its counter intuitive but that doesn't mean relativity is wrong or flawed, it just means that some things in the universe don't behave in the same way as everyday physics does.Just something everyone here should remember and take to heart.
There is not a single concept of which I am convinced that will survive and I am unsure whether I am on the right way at all.
Albert Einstein (1949)
Space and time work in strange ways, they manifest themselves differently in different reference frames.
What's really absurd is that MacM and Quantum Quack demand that we conform to their sense of intuition and "common sense".
That's the grounds they cite for why we're supposed to collectively just give up and start over again from 1900,
In the case of MacM, at least the guy has indicated a fairly impressive technical background in his respective fields. From all indications it seems he has a good background in applied mathematics including calculus, and I can tell that he's at least worked with the Lorentz transformations, even if he also seems (from my POV) to have had some trouble understanding the full consequences.
What if light doesn't have a medium or aether, but is pushed by gravitational fields?
Physicists know relativity is not an 'ultimate theory', that it's almost certain something will come along to replace it but that doesn't automatically make you right in your particular criticisms. Your example of accelerating giving length contraction giving shorter distances isn't a problem, you might not like it because its counter intuitive but that doesn't mean relativity is wrong or flawed, it just means that some things in the universe don't behave in the same way as everyday physics does.
Quite frankly I'd be amazed if there wasn't counter intuitive phenomena in the universe, given intuition is just our way of saying "I expect things to follow my experience" and our experience of the universe is tiny.