Gravity

Originally posted by DeepThought
Why don't you try publishing your idea that time dilation causes gravity?

LOL
I hope he is stupid enough to do just that. That would be hilarious. He would become a gigantic laughing stock of non-stop ridicule -a person who isn't a scientist and and understand no physics at all but under the delusion that he understands it all and speaks a complete load of gibberish about it.

Originally posted by humy

You could say that both are the same as gravitational time dilation.

Why?

I think you are making the mistake of thinking gravity has an explanation at all.

How would you know when you don't understand anything about it?

Can you explain what causes gravitational time dilation?

There are peopl ...[text shortened]... rter than you are that can but you would have insufficient intelligence to understand any of it.

So you think gravity causes time dilation? I suppose you think the cart pushes the horse and water skiers push the boat.

Why don't you explain how gravity causes time dilation? You are intelligent enough to do that, right? What is your source of information?

Originally posted by humy
LOL
I hope he is stupid enough to do just that. That would be hilarious. He would become a gigantic laughing stock of non-stop ridicule -a person who isn't a scientist and and understand no physics at all but under the delusion that he understands it all and speaks a complete load of gibberish about it.

Physics departments get sent people's home spun fundamental theories all the time.

Originally posted by DeepThought
Physics departments get sent people's home spun fundamental theories all the time.

Yeah, I get some automated spam occasionally.

Have you seen this awesome website?

http://vixra.org/

Originally posted by Metal Brain
So you think gravity causes time dilation?

I didn't say this and don't know where you got that from.

But, now you brought that up, if we go slightly off-topic here now: if one is to be pedantic, one has to be a bit cautious with one's use of the word "cause" as well as assuming that a relationship between two things necessarily involves "cause" and "effect". (does the circumference of a circle divided by its diameter "cause" approximately 3.14159 ? Day is correlated with night because day is always followed by night -so does day "cause" night? -I hope you now see why we must be just a bit cautious with one's use of the word "cause" )

However, having said that, an expert on relativity on this would generally agree with the statement "gravity causes time dilation" but noting that there are also other "causes" of time dilation not involving gravity.

http://physicsworld.com/cws/article/news/2010/feb/17/gravitys-effect-on-time-confirmed
"...Gravity’s effect on time confirmed..."
-and if it is permitted to say gravity "effects" time (more specifically, time dilation ), surely it is also permitted to say time dilation can be "caused" by gravity.

However, even with the 'loosest' use of the word "cause", an expert on relativity would generally strongly disagree with the statement that "time dilution causes gravity".

Originally posted by DeepThought
Physics departments get sent people's home spun fundamental theories all the time.

I wonder what they generally do with it? Just delete it all I suppose. I wonder if such span is sometimes funny ... for all the wrong reasons.

Originally posted by humy
I didn't say this and don't know where you got that from.

But, now you brought that up, if we go slightly off-topic here now: if one is to be pedantic, one has to be a bit cautious with one's use of the word "cause" as well as assuming that a relationship between two things necessarily involves "cause" and "effect". (does the circumference of a circle ...[text shortened]... would generally strongly disagree with the statement that "time dilution causes gravity".

"one has to be a bit cautious with one's use of the word "cause" as well as assuming that a relationship between two things necessarily involves "cause" and "effect"."

I agree. I was very deliberate in using the word "cause" when I asked you if you thought gravity caused time dilation. I don't insist that time dilation causes gravity, but rather time dilation is gravity. Your statement suggesting being cautious with "cause and effect" is well justified. I will make an effort to avoid the confusion that can result in carelessly using those terms incorrectly if you agree to do the same.

I don't suggest that most experts on relativity would agree with my assertion regarding time dilution. I'm not competing in a popularity contest. I could care less what most people think. Can you prove me wrong?

Originally posted by Metal Brain
So you think gravity causes time dilation? I suppose you think the cart pushes the horse and water skiers push the boat.

Why don't you explain how gravity causes time dilation? You are intelligent enough to do that, right? What is your source of information?

I have two degrees in Physics, Kazet is actively engaged in academic research as a physicist, googlefudge has a physics background, and Adam Warlock is a physicist. I don't know about humy, I can't remember. Basically you can't move in this forum for physicists. I had an undergraduate course in General Relativity, a course in differential geometry and my thesis title was Polymerisation of 2D Quantum Gravity models. I am to all intents and purposes infallible in this field as far as discussions in this forum are concerned.

Earlier I was trying to ask a series of questions to get at the root of your misunderstanding, but gave up when you tried to bring weather maps into it. Having looked back through the thread I think you have the concepts of proper time and time dilation confused.

Proper time is the length of a line interval in spacetime. It is the generalisation of Pythagoras' theorem for 4 dimensional pseudo-Riemannian manifolds. In Special Relativity the proper time along the straight path of a moving body is:

c²dτ² = c²dt² - dx² - dy² - dz²

where dτ is the interval of proper time. dt is the time elapsed for some observer, and dx is the distance travelled along the x-axis. c is the speed of light. Suppose the motion is along the x-axis so that dy = dz = 0 and v = dx/dt. We get:

dτ = dt√(1 - v²/c² )

so:

dt = dτ/√(1 - v²/c² )

Or that a co-moving observer, one keeping pace with the moving body will have a clock running slower by this factor. This is time dilation in special relativity.

In General Relativity the space-time is curved. The Einstein Field equations relate curvature to energy density, when they are solved on gets a formula for a line element. For a spherically symmetric, massive body the surrounding space is described by the Schwarzschild metric which is:

c²dτ² = c²A(r)dt² - B(r)dr² - r²(dθ² + sin²θ dφ² )

where
A(r) = 1 - rₛ/r
B(r) = 1/A(r)
and rₛ = 2GM/c², the famous Schwarzschild radius.

These coordinates correspond to what an asymptotic observer would see. For an observer stood at the north pole (so we can ignore the rotation of the earth), dr = 0 as their radial distance doesn't change. dθ doesn't change, that's the lattitude, in polar coordinates at the pole sin(θ ) = 0, so we are left with:

using g = GM/r², we have:

dτ = dt√A(r) = dt√(1 - 2GM/rc² ) = dt√(1 - 2gr/c² )

g = 9.81 m/s², r = 6.37 * 10⁶m, c = 3 * 10⁸m/s
so let x = gr/c² ~ 6.94*10⁻¹¹

Using the small x expansion for the square root:

dτ ≈ dt (1 - gr/c² ) = dt(1 - 6.94*10⁻¹¹ )

So a clock at the North Pole will lose a second relative to a co-moving clock a large distance from Earth every 456 or so years.

I've presented two calculations of time dilation. One due to relative motion in the absence of a gravitational field and one for stationary observers in the presence of a gravitational field. If all you knew was the time dilation you couldn't tell if it was due to gravity or relative motion. So this should be enough to show it is an effect and not a cause.

Originally posted by Metal Brain
"one has to be a bit cautious with one's use of the word "cause" as well as assuming that a relationship between two things necessarily involves "cause" and "effect"."

I agree. I was very deliberate in using the word "cause" when I asked you if you thought gravity caused time dilation. I don't insist that time dilation causes gravity, but rather time ...[text shortened]... eting in a popularity contest. I could care less what most people think. Can you prove me wrong?

I don't suggest that most experts on relativity would agree with my assertion regarding time dilution.

NO expert on relativity would agree with your assertion.

Can you prove me wrong?

What would the point be of showing you “proof” you cannot comprehend? You wouldn't 'see' the proof because you wouldn't know what any of it means. I would have to show you immensely complex equations of general relatively to explain it all and it normally takes MANY YEARS for someone to learn and understand it all. I only know some of the very basic principles and never assume I even come close to knowing it as well let alone better than the real experts on it.
GIVEN you are not an expert on relatively nor even understand it, your default assumption should be, until if and when you have evidence to the contrary, the experts are generally right about relativity and understand it far better than you which, because you are making an assertion that they would ALL strongly disagree with, means, in this case, assuming you are wrong. Not even I think I have any possible chance of come up with a better theory or better understanding of it (than the real experts ) and yet I understand it far better than you do.

Originally posted by DeepThought
I have two degrees in Physics, Kazet is actively engaged in academic research as a physicist, googlefudge has a physics background, and Adam Warlock is a physicist. I don't know about humy, I can't remember. Basically you can't move in this forum for physicists. I had an undergraduate course in General Relativity, a course in differential geometry and ...[text shortened]... o gravity or relative motion. So this should be enough to show it is an effect and not a cause.

Do you have any thoughts on why quasars don't show an apparent time dilation?

http://phys.org/news190027752.html

Originally posted by Metal Brain
Do you have any thoughts on why quasars don't show an apparent time dilation?

http://phys.org/news190027752.html

DeepThought just proved you wrong, I'm eager to see your response to that.
If you avoid his proof, then you admit you lose in this thread. Did you even understand the proof?

Originally posted by DeepThought
I have two degrees in Physics, Kazet is actively engaged in academic research as a physicist, googlefudge has a physics background, and Adam Warlock is a physicist. I don't know about humy, I can't remember. Basically you can't move in this forum for physicists. I had an undergraduate course in General Relativity, a course in differential geometry and ...[text shortened]... o gravity or relative motion. So this should be enough to show it is an effect and not a cause.

Yes, time dilation results from motion. If you have been following my post you already know I was aware of that. Being at the equator instead of the north pole results in more motion. You overlooked the motion of the earth's orbit around the sun. That also contributes to time dilation. The sun moves though the galaxy so that would be a factor as well. Tell me something I don't know.

You pointed out that time dilation can take place from both gravitational and motion at the same time. I would expect that. How does that establish cause and effect?

Originally posted by Metal Brain
Yes, time dilation results from motion. If you have been following my post you already know I was aware of that. Being at the equator instead of the north pole results in more motion. You overlooked the motion of the earth's orbit around the sun. That also contributes to time dilation. The sun moves though the galaxy so that would be a factor as well. Te ...[text shortened]... onal and motion at the same time. I would expect that. How does that establish cause and effect?

I don't think that you really understand what DeepThought wrote...

Originally posted by FabianFnas
DeepThought just proved you wrong, I'm eager to see your response to that.
If you avoid his proof, then you admit you lose in this thread. Did you even understand the proof?

There you go. Would you like to contribute something? Are you still upset about the global warming thread? Does it bother you that climate models are not reliable like you want them to? Does it disappoint you that predictions of climate change doom and gloom are questionable at best? I would think you would be happy the sky is not falling.

Originally posted by FabianFnas
I don't think that you really understand what DeepThought wrote...

Do you have anything to contribute or are you just going to guess about what I am thinking and not thinking? If you think you can read minds why don't you make a lot of money playing poker?