Time Dilation experiments?

[narrator]

Hi all,

I'm having a discussion with a friend. I hope this is the right forum.

My friend's first issue: He believes in science, but does not believe in time-dilation. He thinks that, in the atomic clocks at altitude experiment, the clocks just work differently because of less gravity, like that somehow has a mechanical effect.

His second issue: He says that since time does not have a physical component, he does not see how it can affect mass.

To the first issue, I told him how Einstein's famous equation shows time dilation. I also explained that time dilation shows up in experiments with the LHC, all at ground level, and how the Ives-Stilwell experiments show it as well.

To his second issue (and please correct me if I'm wrong) I said C is distance over time, so you can resolve Einsten's equation to show that time can affect mass, or energy, or both.

Can anyone point to other experiments that demonstrate time-dilation?

Your input is very much appreciated. Thank you.

 

[Frabjous]

Does he use GPS?
https://www.astronomy.ohio-state.edu/pogge.1/Ast162/Unit5/gps.html

 

[narrator]

Does he use GPS?
https://www.astronomy.ohio-state.edu/pogge.1/Ast162/Unit5/gps.html

Yeah, I presented that one early. He thinks it's like the atomic clocks thing. He reckons it's the different gravity on GPS satellites, not time dilation. I said yes, it's the different gravity, causing time dilation but he's not having it. His reasoning comes back to time having no physical aspect, so how can it affect mass or be affected by mass.

 

[Dale]

He believes in science

Then show him the science: https://math.ucr.edu/home/baez/physics/Relativity/SR/experiments.html

Any alternative explanation must explain all of these experiments quantitative. Meaning not just trends but the specific numerical values measured.

the clocks just work differently because of less gravity, like that somehow has a mechanical effect

That is a non-starter because it has been observed in muons which have no internal parts to be mechanically affected.

 

[Vanadium 50]

You might consider not engaging with someone whose mind is already made up. As they say, never wrestle with a pig. You both get dirty, the pig likes it, and spectators may not be able to tell the difference.

 

[russ_watters]

Yeah, I presented that one early. He thinks it's like the atomic clocks thing. He reckons it's the different gravity on GPS satellites, not time dilation. I said yes, it's the different gravity, causing time dilation but he's not having it.

Note that there are two separate effects, one is indeed due to gravity and the other due to speed.

His reasoning comes back to time having no physical aspect...

What's a "physical aspect"?

In any case, if the experiments show the relationship you have to accept it or you're just refusing to accept reality. The "why" can come later.

 

[narrator]

Then show him the science: https://math.ucr.edu/home/baez/physics/Relativity/SR/experiments.html

Any alternative explanation must explain all of these experiments quantitative. Meaning not just trends but the specific numerical values measured.

That is a non-starter because it has been observed in muons which have no internal parts to be mechanically affected.

Thanks Dale. I checked the link and was especially happy to see the Bailey et al experiment observing muons. From the sounds of the description, I'm guessing the experiment was conducted at the LHS. My friend could not then suggest there was any height differential as the muons circulated.

 

[narrator]

Note that there are two separate effects, one is indeed due to gravity and the other due to speed.

What's a "physical aspect"?

In any case, if the experiments show the relationship you have to accept it or you're just refusing to accept reality. The "why" can come later.

Thanks Russ.
Speed yes, C = distance/time. I said to him, you can resolve Einstein's equation for any of the variables, including time, which means time can indeed affect any of the other variables.

He says he uses "rudimentary logic". Regarding "physical aspect", I'll quote him: "After all, time has no physical properties and therefore cannot “dilate” and is not subject to ANY physical manifestations."

As for experiments, he thought the twin atomic clock experiment was the only "proof" of time dilation and his explanation for why the clocks were different was because of different gravity having a physical affect, not time dilation.

The conversation started with the Universe expanding faster than light because space itself is expanding. His response to that was, and I quote, he asked me for "PHYSICAL evidence that space can allegedly bend, fold, propell objects, and do handstands and somersaults AND expand into itself". Along the way that led to time dilation. He's cranky, but asks interesting questions.

Since I mentioned the LHC and the Ives-Stilwell experiment to him, a day ago, I haven't heard back, but I'm expecting a rebuttal. The Bailey et al experiment might make a mention.

But as Vanadium 50 says, I might just be "wrestling with a pig".

 

[Dale]

he asked me for "PHYSICAL evidence

The link contains that. Literally hundreds of experiments from astronomical scales to human scales to subatomic scales. Covering all of the fundamental forces. Including observations of man made lab phenomena and natural phenomena. A few retrospective “predictions” but primarily actual predictions of experiments that had not previously been performed.

Scientists don’t accept relativity because Einstein told us. We accept it because nature told us, over and over and over again. The physical evidence is literally overwhelming.

 

[phinds]

But as Vanadium 50 says, I might just be "wrestling with a pig".

Why is "might be" in that sentence?

 

[Ibix]

he asked me for "PHYSICAL evidence that space can allegedly bend, fold, propell objects, and do handstands and somersaults AND expand into itself".

It doesn't do any of those things.

 

[narrator]

It doesn't do any of those things.

What, no handstands? :p

 

[Ibix]

What, no handstands? :p

Literally none of the sentence I quoted.

Fundamentally, the problem is that your friend has a set of misconceptions about the physics of spacetime that are very common in people who only read pop-sci and don't actually know the mathematical models. Pop-sci has a similar relationship to physics that Benedict Cumberbatch has to Alan Turing. Ask him what he would think of someone who watched The Imitation Game and then spouted off about how he doesn't think cryptanalysis makes any sense.

No matter how hard you try you simply cannot condense decades of study and knowledge into a two hour film. The same applies to pop-sci. It can give you a flavour. At best. It's probably a lot more honest than a Hollywood treatment, but it'll never be truly accurate because the intended audience simply doesn't have time to develop the subject properly. You can study physics in your spare time, but you need actual textbooks and it's hard work (physicists don't use complicated maths for fun - it's because it's the only accurate way to model these things). Spacetime Physics by Taylor and Wheeler (free to download via Taylor's website) or Relativity for the Enthusiastic Beginner by Morin (cheap to download) are a good start, and then Carroll's notes on General Relativity (free to download) are good sources if your friend wants to learn real physics rather than armchair quarterbacking about it. He may need to learn some non-relativistic mechanics beforehand.

 

[phinds]

I'm having a discussion with a friend. I hope this is the right forum.

There IS no forum that will help you defeat willful ignorance. Your friend is obviously a conspiracy theorist, the conspiracy in his case being that scientists just make stuff up and/or don't know what they are talking about. No amount of rational argument will change such a moronic point of view.

 

[narrator]

Literally none of the sentence I quoted.

Fundamentally, the problem is that your friend has a set of misconceptions about the physics of spacetime that are very common in people who only read pop-sci and don't actually know the mathematical models.

Thanks Ibix, I totally agree.

He's actually a bit of a knob who says he's been reading about it for over 30 years and uses "rudimentary logic" to come to his conclusions.
Check this quote from him:
"I'm actually very curious how practically everyone doesn't see the inescapable logic here!"
Then he adds:
"I suspect many universities are polluting students minds during the last couple of decades."

It's now about 36 hrs since I gave him the extra evidence. I suspect he's pulled his head in a bit. But you never know. If he does come back to me about this, I might suggest the downloads you recommended.

 

[narrator]

There IS no forum that will help you defeat willful ignorance.

I suspect you're right. I'll reply here if he accepts my response.

 

[narrator]

The link contains that. Literally hundreds of experiments from astronomical scales to human scales to subatomic scales.

Many thanks, Dale. That's an important detail, the variety of experiments over a variety of scales.

 

[Ibix]

He's actually a bit of a knob who says he's been reading about it for over 30 years and uses "rudimentary logic" to come to his conclusions.

I bet he "may not understand the maths but he understands the concepts".

"I'm actually very curious how practically everyone doesn't see the inescapable logic here!"

By "logic" he means "verbal reasoning", and he's reasoning from imprecise jargon. The actual logic used is the maths, into which we can plug the output of some sensors and get the predicted output of some sensors at another time.

For example, the position of Mercury on the night sky does not quite match Newtonian physics' predictions. This fact was known before Einstein, and the fact that his curved spacetime model predicts it correctly is evidence of the accuracy of its logic.

 

[narrator]

For example, the position of Mercury on the night sky does not quite match Newtonian physics' predictions. This fact was known before Einstein, and the fact that his curved spacetime model predicts it correctly is evidence of the accuracy of its logic.

If I recall correctly, that started with Le Verrier and his "discovery" of the hypothetical planet Vulcan in the 19th century. I had forgotten the curved spacetime aspect of that. Thank you for reminding me!

 

[Vanadium 50]

he's been reading about it for over 30 years

You can tell him, "Don't worry. With practice your reading speed will improve."

 

[FactChecker]

If your friend resorts to vague intuition when faced with all evidence, then there is no hope. If his belief gives him a vague alternative in every situation, there will be no way to distinguish SR time dilation from his belief.
You must make him commit to a concrete alternative theory and find an experiment that defeats that theory.

 

[PeterDonis]

He thinks that, in the atomic clocks at altitude experiment, the clocks just work differently because of less gravity

If by "less gravity" he means that the "acceleration due to gravity", g, is less, that won't work. Gravitational time dilation depends on the gravitational potential, not the acceleration.

 

[Dale]

He's actually a bit of a knob who says he's been reading about it for over 30 years and uses "rudimentary logic" to come to his conclusions.

Scientists use experimental evidence instead. If your logic disagrees with experiment then it is wrong, no matter how personally appealing or compelling.

 

[FactChecker]

the clocks just work differently because of less gravity, like that somehow has a mechanical effect.

Check this quote from him:
"I'm actually very curious how practically everyone doesn't see the inescapable logic here!"

It's ironic that your friend can not say how "clocks just work differently" yet he calls it "inescapable logic". What logic?

I actually feel sorry for him because he can not appreciate the beauty of SR and GR. Those theories start by accepting that the speed of light is constant and the equivalence principle and end up with conclusions about E=Mc^2, the nature of gravity, and more -- all with amazing accuracy.

 

[Ibix]

I actually feel sorry for him because he can not appreciate the beauty of SR and GR. Those theories start by accepting that the speed of light is constant and the equivalence principle and end up with conclusions about E=Mc^2, the nature of gravity, and more -- all with amazing accuracy.

Just to add to this - GR is genuinely complicated, but SR isn't really any harder than Euclidean geometry. If you can handle Pythagoras' Theorem then you have the mathematical chops to handle SR, with the caveat that you'd be limited to idealised toy problems unless you also knew the basics of calculus.

Where people seem to stumble with relativity is largely either not understanding Galileo's take on relativity or being unable to accept that "time" isn't some mysterious global parameter that everyone agrees on.

 

[Vanadium 50]

If by "less gravity" he means that the "acceleration due to gravity", g, is less, that won't work. Gravitational time dilation depends on the gravitational potential, not the acceleration.

Perhaps more to the point, the gravitational acceleration where the muons interact is only a few percent different that at the surface. Not that different from the poles vs. the equator which is 1/2 a percent.

 

[FactChecker]

Then show him the science: https://math.ucr.edu/home/baez/physics/Relativity/SR/experiments.html

Any alternative explanation must explain all of these experiments quantitative. Meaning not just trends but the specific numerical values measured.

That is a non-starter because it has been observed in muons which have no internal parts to be mechanically affected.

Yes! And isn't it strange that the effect on all of those subjects is exactly the same slowdown, whether they have a variety of mechanical parts, are massive planets orbiting the Sun, or are so tiny they have no mechanical parts at all like muons. And the simplest sub-atomic particles show the change based only on relative velocity. If your friend works on intuition, the only intuitive explanation is time, itself, changes due to time dilation.

 

[narrator]

You must make him commit to a concrete alternative theory and find an experiment that defeats that theory.

If only... sigh. I linked him a couple of times to sites with explanations. He took offense, because he knows all that and has been reading it for 30 years. smh.

If by "less gravity" he means that the "acceleration due to gravity", g, is less, that won't work. Gravitational time dilation depends on the gravitational potential, not the acceleration.

His belief is even more basic than that. Less gravity means there's a mechanical difference. Maybe he thinks atomic clocks have pendulums. lol

I actually feel sorry for him because he can not appreciate the beauty of SR and GR.

I would love to have been in young Einstein's shoes just for that one moment when his new theory explained the precession period of Mercury. What a thrill.

If you can handle Pythagoras' Theorem then you have the mathematical chops to handle SR, with the caveat that you'd be limited to idealised toy problems unless you also knew the basics of calculus.

I learned calculus 44 years ago. I wish I'd kept it up. I was the only one in my engineering math class who passed calculus, first time.

Perhaps more to the point, the gravitational acceleration where the muons interact is only a few percent different that at the surface. Not that different from the poles vs. the equator which is 1/2 a percent.

Maybe that's also a part of why people like my friend struggle. People often struggle with the very large and the very small - distance and time.

If your friend works on intuition, the only intuitive explanation is time, itself, changes due to time dilation.

It makes clear sense to me. But I think he's the epitome of the stubborn old man, even though we're both in our late 60's.

 

[PeterDonis]

Not that different from the poles vs. the equator which is 1/2 a percent.

Which also is a good counterexample since clocks on the geoid at the poles and the equator run at the same rate even though g is different.

 

[PeterDonis]

He took offense, because he knows all that and has been reading it for 30 years

There are people responding to you in this thread (including me) who have been studying this area of physics (not just "reading" but actually working problems posed in textbooks and looking at the actual evidence) for longer than that.

 

[PeterDonis]

Less gravity means there's a mechanical difference.

Yes, but any "mechanical difference" would have to be based on a difference in g, since that's the "mechanical" aspect of gravity. So, for example, his mental model would predict that clocks on the geoid at the poles should run at a different rate from clocks on the geoid at the equator, because g is different. But in fact they run at the same rate.

 

[gmax137]

I wouldn't waste any more mental energy on this friend.

Check this quote from him:
"I'm actually very curious how practically everyone doesn't see the inescapable logic here!"
Then he adds:
"I suspect many universities are polluting students minds during the last couple of decades."

'Nuff said.

 

[narrator]

I wouldn't waste any more mental energy on this friend.

Easy to get caught up in it, hey. But you're right.

 

[gmax137]

Easy to get caught up in it, hey.

Understood!

 

[FactChecker]

I would love to have been in young Einstein's shoes just for that one moment when his new theory explained the precession period of Mercury. What a thrill.

Yes! The part that really fascinates me is how he must have reacted when he realized that GR explained the nature of gravity. I wonder if he expected that.

PS. On the other hand, Einstein accomplished so many profound things that it might not have been so amazing to him.