Twin paradox

Thread Starter

Motanache

Joined Mar 2, 2015
481
https://en.wikipedia.org/wiki/Twin_paradox

True or not?
Obviously, you can repeat things already written.
And consider me stupid that I do not understand them.

The problem is that in this reasoning we consider the Earth fixed and the spacecraft as moving. That's why the brother in the spacecraft will be younger than the brother on Earth.

But from the perspective of his brother in the space ship, he could be fixed, and the Earth is moving. The reasoning goes aut. The brother on Earth should be younger.


Experiment with the two planes that have atomic clocks mounted on them, we can comment.
 

nsaspook

Joined Aug 27, 2009
6,499
We see and use the effects of General/Special Relativity daily with GPS and speedy atomic clocks that allow us to calculate locations (using 3D trilateration) on earth with the proper relativistic corrections to the Newtonian universe. No need for another experiment to prove what's already an established fact of time dilation.

http://physicscentral.com/explore/writers/will.cfm
But in a relativistic world, things are not simple. The satellite clocks are moving at 14,000 km/hr in orbits that circle the Earth twice per day, much faster than clocks on the surface of the Earth, and Einstein's theory of special relativity says that rapidly moving clocks tick more slowly, by about seven microseconds (millionths of a second) per day.
http://www.astronomy.ohio-state.edu/~pogge/Ast162/Unit5/sr.html
Central Postulates of Relativity:
The laws of physics are the same for all uniformly moving observers.
The speed of light is the same for all observers.



Consequences:
Different observers measure different times, lengths, and masses.
Only spacetime is observer independent.
"The principles of special relativity are remarkably simple. They are very much simpler than the axioms of Euclid or the principles of operating an automobile. Yet both Euclid and the automobile have been mastered - perhaps with insufficient surprize - by generations of ordinary people. Some of the best minds of the twentieth century struggled with the concepts of relativity, not because nature is obscure, but simply because man finds it difficult to outgrow established ways of looking at nature. For us the battle has already been won. The concepts of relativity can now be expressed simply enough to make it easy to think correctly - thus "making the bad difficult and the good easy."[*] The problem of understanding relativity is no longer one of learning but one of intuition - a practiced way of seeing. When seen with this intuition, a remarkable number of otherwise incomprehensible experimental results are revealed to be perfectly natural."
 
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atferrari

Joined Jan 6, 2004
3,487
Not to derail the thread. My questions: a clock in outer space will match what clock from all the mentioned ones?

The atomick clock at my bench and the space voyager, who would be faster?
 

crutschow

Joined Mar 14, 2008
23,522
Motanache poses an interesting paradox.
You have two twins traveling in separate rockets going in opposite directions in empty space.
So how will they age relative to each other?
What would be the time difference if each ship carried an atomic clock?
It would seen that each one would think the other one was aging less (time going slower) but obviously both can't be.

Another paradox.
You have two atomic clocks in opposite orbit around the earth at the same orbital speed.
Obviously both would slow down by the same amount from an earth clock.
But even though both are moving at significant velocity relative to each other, there is no relative change in time.

My thought is that acceleration/gravity gets into the mix somehow, thus avoiding the paradox.
That is, the frame of reference that is accelerated is the one that loses the time relative to the unaccelerated frame.
For example, the clock in orbit is constantly being accelerated by gravity as it goes around the earth.
 
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Thread Starter

Motanache

Joined Mar 2, 2015
481
We see and use the effects of General/Special Relativity daily with GPS and speedy atomic clocks that allow us to calculate locations (using 3D trilateration) on earth with the proper relativistic corrections to the Newtonian universe. No need for another experiment to prove what's already an established fact of time dilation.

http://physicscentral.com/explore/writers/will.cfm


http://www.astronomy.ohio-state.edu/~pogge/Ast162/Unit5/sr.html
My question remains. Why do you consider the Earth fixed?

For example, a satellite is fixed relative to the Sun.
As a distance. The Sun has its own rotation motion around its own axis Earth the same.
From Earth we will see the satellite moving.

But the satellite is fixed and the Earth is moving due to its rotation.
So the Earth moves and the satellite is fixed.

Logically it would be time for Earth to get harder. (The clock remains behind on Earth)
In fact, the satellite clock will be behind.

Who's fixed and who's moving?
 

Thread Starter

Motanache

Joined Mar 2, 2015
481
You have two twins traveling in separate rockets going in opposite directions in empty space.
.
Only if you include the Earth or the Sun as a fixed reference system.

If both move at equal speed in module but in the opposite direction Related to Earth, twins will have the same age.

If one of the ships travels with a very low speed related to Earth
And the other one ship travels with a very low speed related to Earth,

The brother who travels faster related to Earth will be younger. Strange, is not it ?
 
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crutschow

Joined Mar 14, 2008
23,522
Only if you include the Earth or the Sun as a fixed reference system.
But if it's all relative it shouldn't make any difference whether there's an Earth or Sun around.

That's why I think it also involves acceleration of the two bodies.
 
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Thread Starter

Motanache

Joined Mar 2, 2015
481
Acceleration is in fact derivative of speed related to time.
Time has the same flowing direction.

The discussion is down to speed
 

Thread Starter

Motanache

Joined Mar 2, 2015
481
Michelson could not demonstrate the absence of ether.
If he did not notice any difference in the interference figure, it does not mean the difference does not exist.
Maybe it was so small that she could not measure it.

I suspect that a larger mass body is more fixed because it moves ........ the ether.

I know it's stupid.

I've solved school problems with the formula of time dilation. And I passed the exam.
I always had another idea of these things, but I was advised do not talk about it at school that I do not pass the exam anymore.
 

atferrari

Joined Jan 6, 2004
3,487
Only if you include the Earth or the Sun as a fixed reference system.

If both move at equal speed in module but in the opposite direction Related to Earth, twins will have the same age.

If one of the ships travels with a very low speed related to Earth
And the other one ship travels with a very low speed related to Earth,

The brother who travels faster related to Earth will be younger. Strange, is not it ?
I think I understand you somehow. It would be easier having a master reference point serving as really fixed point, be it the center of the Universe, bottom or top.

As a seaman I am used to latitude/longitude for the position and the North to refer course and bearings to, so, many years ago, I asked to someone in NASA, how spacecrafts managed to know their position out there. The answer was, relative to celestial bodies in way and not to a specific point.

Maybe asking for that capital reference is just a hope we will never have satisfied.
 

nsaspook

Joined Aug 27, 2009
6,499
Michelson could not demonstrate the absence of ether.
If he did not notice any difference in the interference figure, it does not mean the difference does not exist.
Maybe it was so small that she could not measure it.

I suspect that a larger mass body is more fixed because it moves ........ the ether.

I know it's stupid.

I've solved school problems with the formula of time dilation. And I passed the exam.
I always had another idea of these things, but I was advised do not talk about it at school that I do not pass the exam anymore.
You know the correct answer but you don't really accept it or the experimental, observation and operational evidence that it's correct (extremely successful with recent gravitational wave events) in this example.

Don't be a crank because of your own conceptual misunderstandings, they are not flaws in the theory (ex. the twin paradox).
http://theconversation.com/why-is-einsteins-general-relativity-such-a-popular-target-for-cranks-49661
A pivotal moment in relativity’s history is Albert Michelson and Edward Morley’s demonstration that the speed of light didn’t depend on its direction of travel nor the motion of the Earth.

Of course, since 1887 the Michelson-Morley experiment has been confirmed many times. Modern measurements have a precision orders of magnitude better than the original 1887 Michelson-Morley experiment, but these don’t feature prominently in popular histories of science.

Interestingly many pseudoscientists are fixated on the original Michelson-Morley experiment, and how it could be in error. This fixation assumes science is so linear that the downfall a 19th century experiment will rewrite 21st century physics. This overlooks how key theories are tested (and retested) with a myriad of experiments with greater precision and different methodologies.
http://math.ucr.edu/home/baez/physics/Relativity/SR/TwinParadox/twin_paradox.html
 
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MrAl

Joined Jun 17, 2014
6,633
https://en.wikipedia.org/wiki/Twin_paradox

True or not?
Obviously, you can repeat things already written.
And consider me stupid that I do not understand them.

The problem is that in this reasoning we consider the Earth fixed and the spacecraft as moving. That's why the brother in the spacecraft will be younger than the brother on Earth.

But from the perspective of his brother in the space ship, he could be fixed, and the Earth is moving. The reasoning goes aut. The brother on Earth should be younger.


Experiment with the two planes that have atomic clocks mounted on them, we can comment.
Hi

I think all the speeds are known. The Earth is moving, so you'd have to know how much faster the other brother is going. If he followed the Earth around the rotation of the sun for example and the Earth brother was at a pole, then they would both be going roughly at the same speed. If the space brother was orbiting the sun at twice the speed of the Earth (one rotation every 6 months), then he'd be going twice as fast and for at least some time moving away.
 

Thread Starter

Motanache

Joined Mar 2, 2015
481
We see and use the effects of General/Special Relativity daily with GPS and speedy atomic clocks that allow us to calculate locations (using 3D trilateration) on earth with the proper relativistic corrections to the Newtonian universe. No need for another experiment to prove what's already an established fact of time dilation.

http://physicscentral.com/explore/writers/will.cfm


http://www.astronomy.ohio-state.edu/~pogge/Ast162/Unit5/sr.html
Do you have any proof that this time dilation respects Einstein's equation?
What speed will you use in this formula?Tangent to orbit?
 

nsaspook

Joined Aug 27, 2009
6,499
The proof is if you calculate without Einstein's SR/GR corrections (satellite clock rate offset corrections) the time and distance navigation calculations don't match the correct coordinates on earth. Sounds like a pretty solid proof of time dilation.

https://en.wikipedia.org/wiki/Error_analysis_for_the_Global_Positioning_System#Relativity

The orbital velocity is ~4 km/s while the observer at the earths equator is less than 500 m/s relative to the center. This requires a small correction of about 1% in the time dilation on the surface vs the center of the earth.
 
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MrAl

Joined Jun 17, 2014
6,633
Do you have any proof that this time dilation respects Einstein's equation?
What speed will you use in this formula?Tangent to orbit?
Hi,

The reason for the GPS problem was mainly because the calculations have to be so darn perfect in order to calculate a position on the earth with high resolution. Usually we dont need this, but when we have certain physical setups the result we get from a calculation that comes from several measurements will not be so accurate unless we start to account for every little thing, such as the way the earth moves. For some earth position resolutions we dont need to include any relativity adjustments, but once we seek a resolution on the order of 1 meter (if i remember right that is the turning point but it could be as large as 10 meters i'd have to look it up again) we have to account for factors that we usually dont have to. In addition to the transformations needed from the basic measurments, we also need a very highly accurate frequency reference so we can make a decent measurement. The frequency standards have to be much better than our normal crystal oscillator.

It might help to look into the Lorentz transformations. Last time i remember having to do this was early to mid 1990's so i'd have to review also to get to any decent calculation results. I suppose that way we could investigate a little deeper.
 

MrAl

Joined Jun 17, 2014
6,633
Hi,

I like the last sentence that states that we have "become dependent on Einstein's conception of space and time".
 

BR-549

Joined Sep 22, 2013
4,938
Motanache......I don't believe it's true. This problem can be explained with a much simpler explanation.

The relative displacement errors are well known and were solved mechanically before digital electronics.

The reason for the modern timing errors is because of the clocks we're using. Atomic vibration is not a stable rate. It can be affected by almost anything. E, M, and G fields. Temp. And of course acceleration.

So unless all your reference clocks are under the same influence.......they have different rates.

I don't think space is related to time. I don't believe you need space for time. I think time is the rate of displacement. An atomic vibration is a dipole oscillation between a proton and an electron. The distance between the two vary at a frequency. This distance can vary under external forces......and it's own inertia under acceleration.

However the proton and the electron have a rotation frequency also. The proton is much higher and in the gamma wavelength. The electron is in the high x-ray range....much lower. These rotational frequencies do not change unless the particle changes state...........and are super stable......under moderate influence or acceleration. Under extreme influence the electron would be the first to change.......so for a stable clock we would want to use the proton. That means a gamma rate clock.

Atomic vibration is analog with environment and particle rotation is digital with environment.

It's not a space/time problem.......it's an engineering problem.

Many people don't realize how treacherous observation and measurement can be. For example.....all of our gravitational theories thru history have had to satisfy and explain the elliptical obit of the earth. And they do.

That's a rabbit hole. The earth's dance with the sun is not elliptical.......it's helical. The sun's trajectory is helical also.

Observations with particles and distant stars can be much more treacherous. And many more rabbit holes.
 

nsaspook

Joined Aug 27, 2009
6,499
Motanache......I don't believe it's true. This problem can be explained with a much simpler explanation.
I'm sure the nice people at LHC that deal with the impact of Einstein’s theory of special relativity (Length contraction, Time dilation, Relativistic mass) on particle accelerators would love your explanations on how their measurement devices operate.

https://web.stanford.edu/~rlbyer/PDF_AllPubs/2005/407.pdf
The predictions made by this new theory are counterintuitive to our natural thinking of space and time and are at first difficult to accept as real physical phenomena. It is difficult to abandon the so-appealing concept of Galilean relativity and the simple addition of velocities. However, one century since its inception numerous physical phenomena are known to us that can only be explained by Einstein’s theory. One very striking example of special relativity is the observed kinematics of accelerating particles in particle accelerators. Einstein already predicted that accelerating electrons gain arbitrarily large kinetic energies as they approach the speed of light, which he argued they can never reach [1]. Thus, once a particle’s speed is close to c, its kinetic energy increases by its apparent increase of mass and not by a change in speed.
http://hyperphysics.phy-astr.gsu.edu/hbase/Relativ/einvel.html
 
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