Question about photons

@metal-brain said
You claim Greene is wrong.

When? About what? You haven't even convinced us you know what he said.

Deepthought doesn't agree with you.

About what?
And it wouldn't matter in the slightest even if he did disagree with me on something because that doesn't mean you are right and what the science says is wrong.

@metal-brain said
You claim Greene is wrong. Deepthought doesn't agree with you. You two are not even on the same page and you expact me to believe deepthought when you don't even agree with him?

I know Brian Greene's qualifications. I don't know anybody's qualifications here. All I know is what people claim on here. Even still, nobody on here has qualifications that come even close to the professor's.

Just on a technical note. Brian Greene, Kazet and I all have identical qualifications, Kazet has a Ph.D. and Greene and I both have a D.Phil. from the same institution. Greene is a Professor, which is a position, not a qualification.

@deepthought said
Just on a technical note. Brian Greene, Kazet and I all have identical qualifications, Kazet has a Ph.D. and Greene and I both have a D.Phil. from the same institution. Greene is a Professor, which is a position, not a qualification.

The only person I know has those qualifications is Brian Greene. I don't believe anyone on here has a Ph.D just because they claim to.

@metal-brain said
What is Brian Greene's exact quote about things not wanting to age? I think you are nit picking at things not meant to be taken too literally. The notion the he is saying things can think about aging is absurd. He is clearly explaining that things move to where time passes slower, not that particles have a brain.

Wouldn't it be easier for you to just admit Brian Greene ...[text shortened]... ravity? You still have not explained why gravity would cause time dilation. How do you explain that?

The technical term is "gravitational time dilation", not "time dilation from matter" [1]. In the simple case of a central, spherically symmetric mass we can avoid problems with relative motion of observers by having a collection of observers whose positions do not change with respect to each other or the central mass. Suppose they are in a straight line radiating from the central mass. To maintain their stationary position they have to generate thrust away from the central mass or be supported by the ground, so they are accelerating. Each of their clocks runs at a different rate, this is what Greene is talking about. However, this is not in itself time dilation, that's just different clock rates. Given two events which each of them observe they will all measure the difference in time between the two events and get different answers. The difference in the duration they measure is what we mean by time dilation. This is the technical definition. Differences in measurements do not cause gravity. This is my principle objection.

There's a problem I discovered with what I was saying earlier. Proper time is not minimized for the geodesic equation, it is maximized, so it should the principle of maximum proper time [2]. There's something called the principle of least time in classical optics and I generalized the name without thinking it through completely. Bear in mind it's about 25 years since I had the course in General Relativity, and in the course I did the lecturer used the "parallel transport" definition on p. 68 of [2] to get to the geodesic equation rather than the proper time method from pp. 69 onwards. I talked about the proper time method because it's easier to explain and seemed, based on your report of his video, to be what Greene was relying on.

[1] https://en.wikipedia.org/wiki/Gravitational_time_dilation
[2] https://arxiv.org/pdf/gr-qc/9712019.pdf
See pp. 68 - 72, these are lecture notes on General Relativity and I've posted the link to give you an idea of the technical complexity of the subject, I'm not seriously expecting you to follow the maths there.

@deepthought said
The technical term is "gravitational time dilation", not "time dilation from matter" [1]. In the simple case of a central, spherically symmetric mass we can avoid problems with relative motion of observers by having a collection of observers whose positions do not change with respect to each other or the central mass. Suppose they are in a straight line radiating from t ...[text shortened]... the technical complexity of the subject, I'm not seriously expecting you to follow the maths there.

I don't like the term "gravitational time dilation" because it implies gravity causes time dilation and it doesn't. People are taking the term too literally.
Greene was not talking about time dilation from velocity. He was talking about gravitational time dilation (time dilation from matter) and Greene was NOT talking about time dilation from velocity at all. You deliberately trying to obfuscate by falsely claiming he was talking about velocity. You need to grow up. Do you always do this to try and avoid admitting you are wrong?

Gravity does not cause time dilation. Why would it? You still have not answered the question. Why would gravity cause time dilation? The reason you are evading the question is because you don't have an answer and you know you are wrong.

@metal-brain said
The only person I know has those qualifications is Brian Greene. I don't believe anyone on here has a Ph.D just because they claim to.

This just shows you have completely moronic delusional paranoia. To us normal people, it is OBVIOUS Deepthought almost certainly DOES have Ph.D because, not only does he 'merely' claims to, but, in addition, unlike you, he has repeatedly shown very clear understanding of relativity that goes not only well beyond the average layperson's but well beyond mine despite me doing some small amount of relativity at university, which would be strangely very highly unlikely if he wasn't highly qualified in the subject!

@metal-brain said
I don't like the term "gravitational time dilation" because it implies gravity causes time dilation and it doesn't. People are taking the term too literally.
Greene was not talking about time dilation from velocity. He was talking about gravitational time dilation (time dilation from matter) and Greene was NOT talking about time dilation from velocity at all. You delibe ...[text shortened]... reason you are evading the question is because you don't have an answer and you know you are wrong.

Where in the above post did I imply that Greene was talking about, as you put it, "time dilation from velocity". When we talk about gravity we talk about a gravitational field, the gravitational field is the non-flat space created by mass distorting space-time around it, differing clock rates are a consequence of this.

@humy said
This just shows you have completely moronic delusional paranoia. To us normal people, it is OBVIOUS Deepthought almost certainly DOES have Ph.D because, not only does he 'merely' claims to, but, in addition, unlike you, he has repeatedly shown very clear understanding of relativity that goes not only well beyond the average layperson's but well beyond mine despite me doing some ...[text shortened]... versity, which would be strangely very highly unlikely if he wasn't highly qualified in the subject!

It's not really proof, an undergraduate who'd done the course could manage this.

@deepthought said
It's not really proof, an undergraduate who'd done the course could manage this.

Yes, but I still think it's very unlikely you would be lying about that.
Perhaps most people might not find it hard to make a very small lie if so motivated, such as saying they got a C+ rather than just a C for an exam. But saying you have a Ph.D when you don't? I think it is surely actually quite hard for most 'normal' people to make such a huge lie. I couldn't. If I could without my conscience bothering me then I guess I would also say I have a Nobel prize and I am a professor if it wasn't for the fact I know I would almost certainly be exposed as a liar for keep saying that.

@humy said
This just shows you have completely moronic delusional paranoia. To us normal people, it is OBVIOUS Deepthought almost certainly DOES have Ph.D because, not only does he 'merely' claims to, but, in addition, unlike you, he has repeatedly shown very clear understanding of relativity that goes not only well beyond the average layperson's but well beyond mine despite me doing some ...[text shortened]... versity, which would be strangely very highly unlikely if he wasn't highly qualified in the subject!

Copy and pasting plagiarized material is not proof of anybody's educational level. Your perception of obvious is perplexing.

@deepthought said
Where in the above post did I imply that Greene was talking about, as you put it, "time dilation from velocity". When we talk about gravity we talk about a gravitational field, the gravitational field is the non-flat space created by mass distorting space-time around it, differing clock rates are a consequence of this.

You describe something 4 dimensional with a two dimensional description and then you use a 4 dimensional description (space-time). I think you are failing to understand time dilation is part of space-time.
Time dilation (1 dimension) bends space (3 dimensions). 3+1=4 dimensions = space-time.

Time dilation and the bending of space-time are the same thing. You need to remember that space-time describes 4 dimensions and time dilation is the additional dimension included in that description. If it was only 3 dimensions it would simply be called "space". add the time dilation and you have space-time.

Now do you understand?

@metal-brain said
Copy and pasting plagiarized material is not

What "plagiarized material"? Show us.

@humy said
What "plagiarized material"? Show us.

You do it all the time. If I had a nickel for every time a guy copy and pasted wikipedia excerpts I would not have to worry about how to pay my bills.

@metal-brain said

Now do you understand?

There would be absolutely no point in either him or the rest of us 'understanding' a single one of your many clearly false assertions.
First you need to actually learn something about what you are talking about. Only then might we listen.

@metal-brain said
You do it all the time. If I had a nickel for every time a guy copy and pasted wikipedia excerpts

copy and pasted wiki quotes doesn't make it "plagiarized material".
Look up "plagiarize" in the English dictionary and then come back to us.