Why time dilation?

[DrProctopus]

Can anyone explain why time dilation occurs at extreme speeds? I understand that it is called for in Relativity, and that it satisfies all of the relevant equations. But, why does it happen? That is, what is the mechanism of action that causes time dilation at extreme speeds?

[Perspicacious]

Time dilation happens symmetrically at all speeds. The effect is just highly noticeable with great asymmetry in the motion when relative speeds are extreme. Why do clocks behave in this way? Because it's the nature of Minkowski spacetime to always yield that outcome for asymmetrical motion. Minkowski spacetime is defined by the Lorentz transformation. A precise interpretation of the mathematics of the Lorentz transformation only tells us how to compute the effect and gives consistent answers. It offers no explanation why. It's just the nature of space and time and mathematics that produces consistent results.

 

http://www.everythingimportant.org/relativity/

[Qfwfq]

<nitpicking=Perspicacious>Minkowski spacetime is defined by the Minkowski metric and the Lorentz transformations are the coordinate transformation for which Minkowski's metric is invariant.</nitpicking>

 

Why? Ask Maxwell, Michelson and Morley.

[HydrogenBond]

One could rationally explain time dilation if one assumes that time was a distinct thing like a particle phenomena. As the time thing gained velocity it would gain kinetic energy and therefore become a more substantial thing with more time substance or time potential allowing it to express longer time. This distinct thing analogy is not that far fetched because time is measured with distinct cyclic changes of state. Physics allows randomness with everything but time. Time is assumed steady like a fluid.

 

If time could be metered out in a random way instead of cyclic way the particle analogy might imply a type of random battery for smaller cyclic changes that will occur until the quanta is exhausted and the battery dies. One analogy is a one shot mutation that is born, grows and expires never to be repeated. It existed randomly in time.

 

Random quanta or even stable time dilation quanta from the creation of the universe could explain why some time cycling events last longer than others. For example, the quarks in protons can cycle for billions of years with its time battery.

[Perspicacious]

More nitpicking:

 

"The geometry of Minkowski space is defined by the Poincaré group."

 

http://en.wikipedia.org/wiki/Poincar%C3%A9_group

http://www.everythingimportant.org/relativity/generalized.htm

[UncleAl]

Can anyone explain why time dilation occurs at extreme speeds?

At any speed. If your physics is Lorentz Invariant Special Relatvity obtains by default. It exactly works without exception in all venues at all scales.

 

http://fourmilab.to/etexts/einstein/specrel/specrel.pdf

Derivation

 

http://relativity.livingreviews.org/Articles/lrr-2001-4/index.html

http://arXiv.org/abs/gr-qc/0311039

http://www.physics.adelaide.edu.au/~dkoks/Faq/Relativity/SR/experiments.html

Experimental constraints on General Relativity

 

http://www.eftaylor.com/pub/projecta.pdf

http://www.public.asu.edu/~rjjacob/Lecture16.pdf

http://relativity.livingreviews.org/Articles/lrr-2003-1/index.html

Relativity in the GPS system

 

http://arXiv.org/abs/astro-ph/0401086

http://arxiv.org/abs/astro-ph/0312071

http://relativity.livingreviews.org/Articles/lrr-2003-5/index.html

http://skyandtelescope.com/news/article_1473_1.asp

Deeply relativistic neutron star binaries

[Qfwfq]

More nitpicking:

 

"The geometry of Minkowski space is defined by the Poincaré group."

:shrug:

 

Wheeeeee!!! ;)

 

In physics and mathematics, the Poincaré group is the group of isometries of Minkowski spacetime.

doesn't mean that Minkowski spacetime is defined by the Poincaré group. Isometries are no more nor less than "transformations that preserve the metric", exactly what I had said. Further, translations are isometries for both Euclid's metric and Minkowski's in a flat space-time so there's no difference between saying Lorentz or Poincaré. In a non-flat space-time translations aren't typically isometries, so Wiki left out a word in that sentence. Throw Wiki in the trash...

;)

[Perspicacious]

If spacetime is a geometry, and if a group is able to determine and thus define a geometry, then what spacetime is defined by the Poincaré group?

 

"Every geometry is defined by a group of transformations, and the goal of every geometry is to study invariants of this group." Klein, Erlanger Program.

 

"Each type of geometry is the study of the invariants of a group of transformations; that is, the symmetry transformation of some chosen space." Stewart and Golubitsky 1993, p. 44.

 

"A geometry is defined by a group of transformations, and investigates everything that is invariant under the transformations of this given group." Weyl 1952, p. 133.

[Qfwfq]

then what spacetime is defined by the Poincaré group?

The flat Minkowski space, of course, because the group preserves the Minkowski metric.

 

The geometry is defined by choosing a metric, afaik, and once a metric G is chosen we can write

 

T^ G T = G

 

and find the group of Ts that are isometries. Mathematicians have a habit of glossing over things, a posteriori, and saying things a bit in the reverse, but they understand what they mean because the are accustomed to decrypting it.

 

To specify the metric by specifying the group of isometries is somewhat contorted, but mathematicians are a rather odd species.

[DrProctopus]

So, getting back to the original question...

 

Basically, the idea is that time is a thing that can be divided into quanta?

 

So, if time is a component of spacetime, and particles are patterns of resonance within spacetime, then time dilation occurs because more units of time are being consumed in transferring the particle/pattern from one unit of spacetime to another unit of spacetime - and thus less units of time are available for the internal motions of an object that would be used to measure time.

 

Is this the basic idea?

[Qfwfq]

:shrug:

 

Time dilatation is just a change of coordinates. An object doesn't "go slower" when it is "moving", it's just that for different observers time will not be equal to the objects proper time. Observers for which the object is at rest will see the same time intervals, all other observers won't.

[DrProctopus]

So...

 

What causes time to not be equal for different observers?

[Perspicacious]

time dilation occurs because more units of time are being consumed in transferring the particle/pattern from one unit of spacetime to another unit of spacetime - and thus less units of time are available for the internal motions of an object that would be used to measure time.

Time is impossible to define without space and the possibility of motion. What you conceive of as moving is irrelevant.

 

One could rationally explain time dilation if one assumes that time was a distinct thing like a particle phenomena. As the time thing gained velocity it would gain kinetic energy and therefore become a more substantial thing with more time substance or time potential allowing it to express longer time.

Why do so many misguided dreamers and misinformed physicists attempt to define space or time with physical particles? Why do so many even try? Only mathematicians are qualified to speak definitively on geometry.

 

Time and motion are irreducible concepts. Space and motion, or space and time, are interconnected concepts.

http://www.everythingimportant.org/relativity/

[Perspicacious]

So... What causes time to not be equal for different observers?

The answer you want is the same as in answering the question, "what is time?" Believe me. The only insight you're going to get to the mystery of time dilation is contained in a mathematical derivation of the Lorentz transformation from the simplest and most intuitive axioms possible. And even that isn't going to explain why our universe obeys the Poincaré transformation group and not Galilean relativity.

 

You're still discontent. You want to know the mechanism. Indications are that you'll accept a metaphysical answer. OK. I'll tell you. God is the mechanism. Are you happy now?

[DrProctopus]

Indications are that you'll accept a metaphysical answer. OK. I'll tell you. God is the mechanism. Are you happy now?

 

You must have me confused with someone else.

 

Surely God has better things to do than intervene every single time some object travels fast, or goes near gravity? Unless... Perhaps he is so busy doing this time-dilation stuff all the time, that he is too busy to fulfill my prayers to suddenly become very wealthy! This could go a long way towards explaining the old guy's absentee landlord behavior.

 

 

Equations that accurately predict the outcome of time dilation experiments are great - but they do not give an intuitive understanding of the underlying process. Surely there must be theories that are entirely consistent with relativity that also explain a mechanism for time dilation?

[Perspicacious]

I define mechanistic philosophy as a religious belief.

 

Equations ... do not give an intuitive understanding of the underlying process.

Some equations give a lot of intuitive understanding to time dilation.

 

Surely there must be theories that are entirely consistent with relativity that also explain a mechanism for time dilation?

Why must there be? There isn't.

[DrProctopus]

I define mechanistic philosophy as a religious belief.

 

I define my butt as a 10 foot narwhale...

 

Defining something doesn't make it so.

 

 

I consider a belief in acausality to be a belief in magic.

 

 

 

I just want to understand why time dilation occurs - this is not a bad thing. Have any physicists attempted to answer this question?