# Einstein view of time

Yes, they are not the same thing at all. And I didn't say they were the same thing. I don't see anything I need to clarify in my post ... can you point out exactly where you think I should clarify?
Well, you did say she was getting younger (as I highlighted in post #239 )

The statement clearly states that according to the accelerating traveler Alice actually gets younger, not that she ages slower. I just wanted a clarification, that's all.

Well, you did say she was getting younger (as I highlighted in post #239 )

The statement clearly states that according to the accelerating traveler Alice actually gets younger, not that she ages slower. I just wanted a clarification, that's all.

Yes, I did say (and I intended to say, and I STILL say) that if he accelerates in the direction AWAY FROM her (and if they are not co-located), then he will legitimately conclude that she gets YOUNGER during his acceleration.

Yes, I did say (and I intended to say, and I STILL say) that if he accelerates in the direction AWAY FROM her (and if they are not co-located), then he will legitimately conclude that she gets YOUNGER during his acceleration.
So, she does not age slower, but actually gets younger? IOW her clock runs backwards?

So, she does not age slower, but actually gets younger? IOW her clock runs backwards?

Yes, ACCORDING TO HIM. But SHE does not agree with him, of course. (And there could be many OTHER observers, who happen to be momentarily co-located with him at the instant that he accelerates, and who are accelerating in various other ways themselves, who disagree with him, AND with her. And all of those observers (including her) are RIGHT!)

Yes, ACCORDING TO HIM. But SHE does not agree with him, of course. (And there could be many OTHER observers, who happen to be momentarily co-located with him at the instant that he accelerates, and who are accelerating in various other ways themselves, who disagree with him, AND with her. And all of those observers (including her) are RIGHT!)
So you are positing that people moving away from each other at relative speeds can actually physically revert to a younger state than say yesterday, even as they are aging in their own frame of referenc?

You do realize that aging is the opposite of getting younger?

So you are positing that people moving away from each other at relative speeds can actually physically revert to a younger state than say yesterday, even as they are aging in their own frame of reference?

Not people who are just moving away from her at a constant velocity ... they all just use the time-dilation result, and conclude that she is ageing at half the rate that they themselves are ageing. But someone who is ACCELERATING in a direction away from her (regardless of whether they are currently moving toward her or away from her) WILL conclude that she is getting younger. She won't agree with them, of course. They are BOTH correct!

To the OP .

Einstein thought that time had form of physical energy , that could change any physical form . He was wrong .

Not people who are just moving away from her at a constant velocity ... they all just use the time-dilation result, and conclude that she is ageing at half the rate that they themselves are ageing. But someone who is ACCELERATING in a direction away from her (regardless of whether they are currently moving toward her or away from her) WILL conclude that she is getting younger. She won't agree with them, of course. They are BOTH correct!

So far wrong does not even register on the wrong scale

But someone who is ACCELERATING in a direction away from her (regardless of whether they are currently moving toward her or away from her) WILL conclude that she is getting younger.
Explain why this happens.

Although I agree with everything that JamesR said, perhaps I can rescue some of Michael's pride......

What makes you think that he has any?

What makes you think that he has any?
Like, perhaps, know have some but can't find, will post photo when do

I can rescue some of Michael's pride......

Rescue away

Explain why this happens.

(The "this" you are talking about above is that someone who is ACCELERATING in a direction away from her (regardless of whether they are currently moving toward her or away from her) WILL conclude that she is getting younger.)

A thorough explanation of why it's true would take WAY too long. But I can tell you that it is based on what the Minkowski diagram says. Minkowski diagrams are graphical representations of the Lorentz equations.

One other thing you need to understand is that when I say that some observer "will conclude that (some other person) is getting younger" I DON'T mean that they see SEE her getting younger with their own eyes (because she is a long way away from him, and what he sees when he looks at her with a telescope, or on a TV screen, is very out-of-date. To determine her CURRENT age, he must allow for how much she has aged during the transit of that image of her. When he makes that CALCULATION, he finds that she has either rapidly gotten older, or rapidly gotten younger, depending on in which direction he is accelerating.

I explain all this in great detail on my webpage:

To the OP .

Einstein thought that time had form of physical energy , that could change any physical form . He was wrong .
Changing physical form would include relative time spans (time blocks) of longer or shorter time frames. no?

(The "this" you are talking about above is that someone who is ACCELERATING in a direction away from her (regardless of whether they are currently moving toward her or away from her) WILL conclude that she is getting younger.)

A thorough explanation of why it's true would take WAY too long. But I can tell you that it is based on what the Minkowski diagram says. Minkowski diagrams are graphical representations of the Lorentz equations.
I'm familiar with Minkowski diagrams.

One other thing you need to understand is that when I say that some observer "will conclude that (some other person) is getting younger" I DON'T mean that they see SEE her getting younger with their own eyes (because she is a long way away from him, and what he sees when he looks at her with a telescope, or on a TV screen, is very out-of-date. To determine her CURRENT age, he must allow for how much she has aged during the transit of that image of her. When he makes that CALCULATION, he finds that she has either rapidly gotten older, or rapidly gotten younger, depending on in which direction he is accelerating.
Okay. I see what you're saying. I also didn't fully appreciate that you're talking about what happens while the observer is accelerating.

I assume your analysis is equivalent to what standard special relativity or general relativity would say.

To determine her CURRENT age, he must allow for how much she has aged during the transit of that image of her
I disagree.
Time travel into the past is impossible. Once a person has reached a certain age they can no longer become younger. A one day old newborn cannot be unborn and be travelling anywhere.

You are asserting that she is "ageing" backwards and this process is observable somehow?
Ageing,
In humans, ageing represents the accumulation of changes in a human being over time, encompassing physical,
psychological, and social changes. Reaction time, for example, may slow with age, while knowledge of world events and wisdom may expand. Ageing is among the greatest known risk factors for most human diseases: of the roughly 150,000 people who die each day across the globe, about two thirds die from age-related causes.

If she is receding from the other traveler at a rate of "c", time will stand still (Einstein) and the worst that can happen is that she does not age at all, but she also does not get younger. The arrow of time cannot be reversed.

It is impossible to reverse the chronology of dynamic spacetime coordinates.

I submit that we cannot see the rest of the universe because it is receding at faster than light from us and time stands still in between. No quantum activity hence no reality, but there is "dark matter" ........

I assume your analysis is equivalent to what standard special relativity or general relativity would say.

It is equivalent to the standard EINSTEIN version of special relativity. General relativity is unnecessary and unhelpful in issues about the twin "paradox". But even when sticking to "standard special relativity", there are still disagreements among physicists about the twin "paradox". Some physicists have adopted a more "modern" approach to special relativity, because they think Einstein's approach was unsophisticated. And some of those physicists don't believe that simultaneity is a meaningful concept. Many of them believe that there are many different simultaneity "conventions" that one can choose from, which itself implies that simultaneity can't have much if any meaning. I think Einstein had it right. I think there is only one valid simultaneity, and I think it is fully meaningful and "real".

It is equivalent to the standard EINSTEIN version of special relativity. General relativity is unnecessary and unhelpful in issues about the twin "paradox".
I'm inclined to agree with you. GR can be used, but it is not necessary. SR is just GR without gravity, and gravity isn't necessary to explain the twin paradox.

But even when sticking to "standard special relativity", there are still disagreements among physicists about the twin "paradox".
Maybe. I don't know what you're referring to.

Some physicists have adopted a more "modern" approach to special relativity, because they think Einstein's approach was unsophisticated.
Well, yes, there have been advances in the way the mathematics is presented and carried out in the 100 years since Einstein. Apart from that, I don't know what you're referring to.

And some of those physicists don't believe that simultaneity is a meaningful concept. Many of them believe that there are many different simultaneity "conventions" that one can choose from, which itself implies that simultaneity can't have much if any meaning.
Really? I haven't come across any of the physicists who believe that simultaneity is a meaningless concept. There are many of those, are there?

I think Einstein had it right. I think there is only one valid simultaneity, and I think it is fully meaningful and "real".
Er... okay. I can't really comment on that, too much. If it's standard special relativity, then I'm unlikely to disagree with you.

Time is within each living being and is therefore subjective.

Time is within each living being and is therefore subjective.
Time is also within dead things, especially dead beings, they deteriorate faster than when they are alive.

Everywhere you can you use the phrase "age', has time associated with it's very existence, dead or alive.

A dead body is out of time.