# Einstein view of time

Discussion in 'General Philosophy' started by Dinosaur, May 6, 2019.

1. ### originHeading towards oblivionValued Senior Member

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So show me where it says that if I accelerate away from my twin that my twin will get younger. Are you really claiming it I accelerate away from earth that time will go backwards?

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The point is [I think!] that you are accelerating away FTL, which anyway is a crazy thought experiment as we know what happens as we approach 'c'
But for the sake of the argument as you approach "c" your time is going slower and slower so that returning to Earth 12 months later after a constant speed of say 99.999% "c" you will be returning to an Earth 230 years in the future.
Once the speed of light is exceeded, time goes faster for you doing the travelling and apparently slower then the stay at home twin. Hence travelling FTL leads to the stay at home twin being younger...Terrible explanation agreed but this may help....
https://www.quora.com/If-we-exceeded-the-speed-of-light-would-we-go-back-in-time

Last edited: Jul 6, 2019
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A modification made after original stuff up!

7. ### Neddy BateValued Senior Member

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Okay, I will show you. Please find this excerpt from the link.

"...two people walking past each other in the street could have very different present moments. If one of the people were walking towards the Andromeda Galaxy, then events in this galaxy might be hours or even days advanced of the events on Andromeda for the person walking in the other direction."

So, if someone is walking back and forth, reversing their directions, then time on Andromeda moves forward and backwards, in theory. This change does not happen in the Andromeda galaxy reference frame, but it does happen for the person who is walking back and forth. It is their reckoning of what is simultaneous in Andromeda that changes, not Andromeda itself.

Last edited: Jul 6, 2019
8. ### originHeading towards oblivionValued Senior Member

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So you say that time goes backwards on earth relative to astronauts as they are accelerating to Mars. Uh, OK.

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9. ### Q-reeusBannedValued Senior Member

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This nonsense has been covered before. The supposed dramatic changes in 'Andromeda present time' from casually walking in opposite directions is nothing more than an impossible extrapolation. That could only be realized if either walker kept walking in a notional straight line for the entire 3+ million years it takes light to traverse between the walker here, and Andromeda. Which strictly assumes a static universe in the interim. Relative motions within a galaxy and between ours and Andromeda are vastly more significant than any walking/bicycling done by individuals of course. Or even just Earht's rotation on it's axis etc. Hence the level of fantasy.

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10. ### Michael 345New year. PRESENT is 72 years oldlValued Senior Member

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Everyone

TIME DOES NOT EXIST

it is difficult to describe non existent but what being non existent means
• it does not go forward
• backward
• up
• down
• get up on toes and pirroet
Only NOW exist and it is the same now for the entire Universe

The separation between stuff in the Universe gives the illusion of stuff happening at different NOWs BECAUSE THE INFORMATION has to travel between the relative points

What are the properties of TIME?
You know those aspects of stuff which exist

My list goes like this

The properties of TIME are

Visual - none
Audio - none
Frequency - none
Mass - none
Position on the periodic table - none
Position in the electromagnetic spectrum - none
Detectability - none
Temperature - none
Tallness - none
Thickness - none
Speed - none
All those properties I have missed - none of those either

Anyone like to add to list especially if you have a property which TIME actually possesses

11. ### Q-reeusBannedValued Senior Member

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I've covered the silliness of 'Andromeda paradox' earlier, but how long will it take Mike before you concede your 'completely general' CADO equation CADO_T = CADO_H - v . L , shown here:
, is nothing of the sort. You never did answer me in an earlier thread, where I pointed out it fails completely for the case of circular motion of traveling twin. Who ages less on an absolute basis wrt home twin. Whereas your eqn incorrectly predicts equal aging. See 3. III. THE CIRCULAR TWIN PARADOX in:
https://arxiv.org/abs/gr-qc/0703090

12. ### originHeading towards oblivionValued Senior Member

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Reported as pseudoscience in the science section. I am tired of you repeating this silliness over and over. Start a new thread in alternative theories of you want to discuss it.

13. ### Mike_FontenotRegistered Senior Member

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You've completely misread, or misunderstood, what that CADO equation for 2 or 3 spacial dimensions says (and you've probably also misunderstood what the one-dimensional CADO equation says). That 3-dimentional CADO equation actually CONFIRMS the fact that if a traveling twin moves at constant speed in a fixed, closed circular path around the home twin at the center of the circle, BOTH twins will agree that the traveler is ageing gamma times slower than the home twin. In that CADO equation, for circular motion the dot product of the velocity v and the radius L is always zero, so the equation says that

or, written more completely, that

where "t" is any given age of the traveler. (ALL of the quantities in the CADO equation are ALWAYS to be understood to be functions of the traveler's age "t", because we take it to be the independent variable, and the other quantities are taken to all be dependent variables.

Maybe you've not yet understood that the quantities CADO_T(t) and CADO_H(t) BOTH always refer to the HOME twin's age when the traveler's age is "t". CADO_H(t) refers to the home twins's age, ACCORDING TO THE HOME TWIN, when the traveler is age "t". CADO_T(t) refers to the home twin's age, ACCORDING TO THE TRAVELER, when the traveler's age is "t". So in this circular motion case, the two twins ALWAYS are in agreement about the correspondence between their respective ages.

14. ### QuarkHeadRemedial Math StudentValued Senior Member

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This is garbage. How can you have a dot product of a vector (velocity, in this case) and a scalar (radius)?

15. ### Mike_FontenotRegistered Senior Member

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At any given position of the traveler on the circular path, r in the CADO equation is a vector of length equal to the scalar radius r, pointing from the center of the circle to the current position of the traveler. v is the velocity of the traveler at that same instant, and it's always perpendicular to the vector r.

16. ### QuarkHeadRemedial Math StudentValued Senior Member

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Actually, Neddy you are not agreeing with your source. The assertion that $\gamma$ is 1 or greater there is that is always unity or greater refers rather to its reciprocal. No matter, it's a minor point.

Ha! I am not trying to trick anyone, I am trying to understand where you are coming from.

Look age is definitely scalar, and as such may well have an inverse. But by common agreement, age is measured using the strictly positive integers. (notwithstanding the fact my daughter proudly announces her age as "eight and three-quarters"). These scalars by construction have no inverse.

17. ### QuarkHeadRemedial Math StudentValued Senior Member

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Embarrassing - you don't even know what a vector is? HINT: It is not something that "points", or rather that is not part of the definition

18. ### Michael 345New year. PRESENT is 72 years oldlValued Senior Member

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Well done

I do note that you appear to believe TIME does exist by your action

How have not bothered to provide a property

Again well done

And there is always Iggy

19. ### originHeading towards oblivionValued Senior Member

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That is correct I am not insane.

20. ### Neddy BateValued Senior Member

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It is a minor point, but gamma = γ = 1 / √(1 - (v²/c²)) which is always greater than or equal to 1. The fraction has a numerator of 1 and a denominator that is always less than or equal to 1. Perhaps you are thinking that gamma is only the denominator, but gamma is actually the whole fraction.

For example, try substituting v=0.866025 and c=1.000000 and you should get a gamma (Lorentz factor) of 2.000000.

I'm just saying that the stay-at-home twin (female) can calculate the traveling twin's age (male) by taking her own age, and dividing it by gamma.

21. ### Neddy BateValued Senior Member

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The thought experiment assumes that earth and Andromeda are both relatively stationary. The only relative motion is walking at constant velocity, either toward or away from Andromeda. SR gives two different 'Andromeda present times' based on the two different directions of walking. So someone walking back and forth in that same manner would say that the 'Andromeda present time' is fluctuating forward and backward, while Andromeda itself always experiences time going forward.

SR does not say that the walker would have to walk for millions of years. SR simply says that the speed of light is constant in all inertial reference frames, and there are two different inertial frames for walking in two different directions. In one frame, Andromeda is relatively moving farther away. In the other frame, Andromeda is relatively moving closer. These different directions must be taken into consideration, and the end result is two different 'Andromeda present times'.

I'm sorry you don't like it, but you are not alone. There are probably more people like you than there are like me and Mike_Fontenot, who simply accept that this is what SR says.

22. ### Mike_FontenotRegistered Senior Member

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You are right. I think most physicists (amateur and professional) are HORRIFIED by the idea that the traveler (he) could legitimately conclude that the home twin (she) rapidly gets younger while he is accelerating in the direction away from her (assuming their separation is sufficiently great). They are willing to accept ANY other interpretation, from the Dolby and Gull "Radar coordinate system" (which is non-causal, in that her current age (according to him) depends on how he will decide to accelerate in the future), to the view that only the proper times of each twin matter, and that their ages can ONLY be compared when they are co-located. In effect, the latter group believes that simultaneity at a distance is a meaningless and useless concept (yet, inconsistently, some of them still quote and make use of the time dilation result, whenever it suits their purposes). I'm amazed that this stuff is still being argued about (by relativity believers, not just relativity deniers) 100 years after Einstein figured it all out! I wonder why they think Einstein spent so much time talking about the Lorentz equations, and simultaneity at a distance.

23. ### Mike_FontenotRegistered Senior Member

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I should also add that I think some physicists these days think that Einstein was an unsophisticated rube, and that more modern approaches are vastly superior to Einstein's treatment of special relativity. I think just the opposite. And I agree with Feynman's characterization of Einstein: Feynman said that Einstein's head was in the clouds, but his feet were firmly planted on the ground. And Feynman continued "The rest of us aren't that tall, and so we have to choose".