Who's familiar with the conversion? - "In 15 years' ship-time they could reach Andromeda

@layman,

Quote:

And, guess what? It has been tested. How? Just use atomic clocks and measure to SEE whose clock slowed down (a la Hafele Keating).

You can put two optical lattice atomic clocks side by side on a table then raise one of them a fraction of an inch, and measure the gravitational time dilation effect. The rate of time keeping changes, and this can be seen empirically. You can put one clock on a sidewalk, and one in a car driving past it at 5 mph and see (with your own eyes) the change in clock rate due to speed. The moving clock slows down. Not both--who woulda thunk?

Quote:

We know that gravity and acceleration cause time to pass more slowly, which is why astronauts aboard the International Space Station experience the passage of time ever so slightly slower than we do on Earth (because it’s moving so fast in orbit). The clock in this study is able to measure the time dilation effects of being raised or lowered just 2cm due to the miniscule gravitational changes of being closer or farther from the Earth’s surface.

http://www.geek.com/science/upgraded-atomic-clock-wont-lose-a-second-for-15-billion-years-1621053/

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Relative simultaneity vs absolute simultaneity

Relative simultaneity as explained by Al:

1.There's a guy standing next to the railroad tracks, who see's a long-ass train coming his way from about a mile away.
2.There's a passenger on that train who is seated exactly at the midpoint of that train.
3. There is an instant, a little later, just a brief instant, where the passenger and the guy standing by the tracks see each other eye-to-eye.
4. At that very instant, two lightning bolts happen to hit the train--one at the very front of the train and one at the very rear.
5. The guy standing by the tracks sees the light from each one hit his eyes at exactly the same time. He therefore says they struck the train "simultaneously."
6. The guy on the train says different. Because he is, while the light is heading his way, going TOWARD the one which hits the front, he sees that one first. Because he is moving AWAY from the one which hit the rear, he doesn't see that one until later.
7. Because he is a complete dumbass, the guy on the train says he is not moving (Al knows he is, though). So, he says they did NOT hit the train at the same time. They were NOT simultaneous.

Conclusion: You just can't say that they happened at the same time because some idiot doesn't agree with you. Simultaneity is relative (frame dependent).

Absolute simultaneity, as explained by me:

1. - 6: same as above.
7. Because he is NOT a complete dumbass, the guy on the train doesn't claim he's not moving. He knows that the mere fact that he didn't subjectively SEE them at the same time, DOESN'T mean the lightning bolts couldn't have struck the train at the same time. He therefore says that he knows (after doing a little calculation) that they must have hit the train at the exact same time, since he is moving.

Conclusion: Both people agree that they hit the train at the same time. This is absolute simultaneity. In this context "absolute" just means "frame-independent." "Frame-independent" just means that the conclusion you reach about simultaneity does not change depending on which frame of reference you see the events from.

Which would you rather base a theory of "physical reality" on?

The subjective mistakes of idiots, or the objective, rational conclusions of sensible men?

I mean, like, does "physical reality" depend on subjective perceptions? Does what I think is real determine what is actually real? Or should what's real govern the way I think?

Decide for yourself. Don't just take Max's answer.

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@layman,

But you are assuming that light travels the same speed in both directions. Something you claimed can't be proven. Ergo, your conclusions are in violation of your own claims.

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@layman,

Quote:

Because he is NOT a complete dumbass, the guy on the train doesn't claim he's not moving.

Does the guy standing next to the railroad tracks claim he's not moving (or is he a complete dumbass)?

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@layman,

Ogg is on a spaceship that is actually motionless. To him the Earth and the train tracks are moving away from where Ogg's spaceship is parked.

It just so happens that the Earth is currently oriented so that where the train track is located on Earth an East bound train is moving towards from where Ogg is sitting motionless. And a West bound train is moving away from Ogg.

This means that Ogg would say an East bound train is going faster than the train tracks. And, it means that a West bound train is going slower than the train tracks.

Are you with me so far, Layman?

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@parados,

Quote:

But you are assuming that light travels the same speed in both directions. Something you claimed can't be proven. Ergo, your conclusions are in violation of your own claims.

1. I'm not claiming that
2. I didn't say it was proven--I asked which interpretation made more sense as a matter of physics. Al's mess aint been proven either
3. http://able2know.org/topic/301703-18#post-6075848 But this paper did say it had been disproven

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@maxdancona,

Quote:

Does the guy standing next to the railroad tracks claim he's not moving (or is he a complete dumbass)?

Yeah, he claims he aint movin relative to the earth.

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@maxdancona,

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Are you with me so far, Layman?

You're certainly not with me, Max. I just got through posting this for you:

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If I want to know who's watch has slowed down, as between mine and a guy's who I see sittin by the tracks as I pass, I KNOW it's mine, not his. And, guess what? This can be tested.

And, guess what? It has been tested. How? Just use atomic clocks and measure to SEE whose clock slowed down (a la Hafele Keating). And, to know this, I don't need to know a damn thing about how fast I (or the earth) is moving with respect to some distant galaxy, Mars, or the CMB. Those aren't even relevant questions in connection with this particular analysis.

1 Reply

@maxdancona,

Quote:

Ogg is on a spaceship that is actually motionless

Descartes wondered if he could just be a brain in a vat, controlled by some evil demon. You ask yourself that a lot, too, Max?

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@maxdancona,

Ask yourself a couple of questions, eh, Max?

1. Why is it, ya think, that if we see a supernova explode tonight, we won't say it happened "right now?" Why would we say it happened 20,000 years ago (or whatever)?

2. Then ask yourself this: What in the hell was Al thinkin?

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@layman,

You are not with yourself Layman. I am trying to point out a core problem with your reasoning. You said

Quote:

The guy standing by the tracks sees the light from each one hit his eyes at exactly the same time. He therefore says they struck the train "simultaneously."

This implies that the guy standing by the tracks is assuming (incorrectly) that he isn't moving. Of course he is standing on the Earth next to tracks attached to the Earth and as you and I and Ogg all know... the Earth is moving.

Then you say...

Quote:

Because he is NOT a complete dumbass, the guy on the train doesn't claim he's not moving. He knows that the mere fact that he didn't subjectively SEE them at the same time, DOESN'T mean the lightning bolts couldn't have struck the train at the same time. He therefore says that he knows (after doing a little calculation) that they must have hit the train at the exact same time, since he is moving.

Notice that the guy on the train is doing calculations... and he comes up with the answer that the first guy is correct, and the first guy thinks (incorrectly) that he isn't moving.

The first guy in your example is incorrect (since he assumes he isn't moving when he is).

The second guy in your example is also incorrect (since after a calculation he comes up with the same conclusion as the first guy.

Only Ogg is correct... since he is the one who isn't moving. And he sure as hell won't see the lightening strike each end of the train at the same time for the same reason the guy on the train won't.

Here is the contradiction in your logic

You are saying that the person who isn't moving is the one who is correct. But then you keep saying the person attached to the earth is the one who is correct. When I suggest we look at things for a person who is actually motionless (i.e. not attached to the Earth) you then claim that it isn't important.

Either being "actually motionless" is important... or it isn't. Make up your mind.

1 Reply

@maxdancona,

Quote:

You said:
The guy standing by the tracks sees the light from each one hit his eyes at exactly the same time. He therefore says they struck the train "simultaneously."

No, that's what Al said

Quote:

This implies that the guy standing by the tracks is assuming (incorrectly) that he isn't moving. Of course he is standing on the Earth next to tracks attached to the Earth and as you and I and Ogg all know... the Earth is moving.

The implied frame of reference was the earth's surface. The guy AINT movin with respect to that.

Quote:

You are saying that the person who isn't moving is the one who is correct. But then you keep saying the person attached to the earth is the one who is correct. When I suggest we look at things for a person who is actually motionless (i.e. not attached to the Earth) you then claim that it isn't important.

1. This isn't even my concoction--It's Al's.
2. The point is the same either way. We are talking about simultaneity (not the speed of light, or anything else) here. After adjustment the two will agree on the TIME that they happened.

If both know the earth itself is moving in a certain direction at a certain speed, they can both adjust for that also. Then they might not still think that the two lights struck the train at the exact same time. That's not the point. The point is that with absolute simultaneity they will AGREE (not DISAGREE) about the time, whatever it is.

Talk to Al about his example if you don't like it. I'm just showing how his example would change if the guy on the train wasn't a complete dumbass.

Again, the point of this example IS NOT "when did they strike?," it's" do we agree on the time they struck, whatever it might be?"

1 Reply

@layman,

Forget about Albert Einstein. You are presenting your view on how the Universe works. You seem to think that you are smarter than Albert Einstein. Ok. Let's assume you are right and Einstein is wrong... and let's run with it.

For this exercise, you are the teacher... I am the student. So teach me how you look at the Universe. If you can answer my questions without any contradictions then I will learn something and you will show me that your view makes sense.

Now please.

Let's take the simultaneity example.

I think we agree that

1. when it comes to lightening bolts hitting a train, different people will measure different things when they measure which lightening bolt hits first. For example the person on the moving train will see one hit before the other. The person on the earth will see something different. A person parked in space will see a third version.

2. according to what you have written, the person who is motionless will see the correct version of which lightening bolt hits first (or whether they hit at the same time).

3) That person is not the person standing next to the train tracks on Earth?

I am just going by what you wrote in your posts (which I have read). Please tell if according you your view of Physics whether this is all correct so far, or explain what I have gotten wrong.

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@maxdancona,

Quote:

You are presenting your view on how the Universe works.

No, not for one second. I'm not talking about "the universe" at all. You're the one who keeps bringing that infathomable topic up. I'm talking about the difference between two competing theories of relative motion, SR and LR, that's all. And I'm just trying to talk about one thing, and one concept at a time. I am certainly NOT trying to talk about everything and every concept in the whole universe all at once.

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@maxdancona,

Quote:

according to what you have written, the person who is motionless will see the correct version of which lightening bolt hits first (or whether they hit at the same time).

No, that's not what I'm saying. You're misinterpreting it. I said

1. ONE, and only one in this example is "truly moving" with respect to the earth. That is the guy on train. The guy on the earth is "truly" motionless, with respect to the earth.
2. I have already explained at some length (as though it needs explaining) why we say he is the one who has accelerated. To deny it, we would also have to deny virtually every known law of physics.
3. The the guy on the trains ALSO KNOWS he's moving wrt the earth. So, to correct for his OWN KNOWN motion he must put him self back into the earth frame for time and distance purposes (but not speed). If there is other known motion that he then shares with the earth, then they can BOTH correct for that.
4. The question here is not "who's correct" on a universal scale, i.e., who is ABSOLUTELY moving. That can't be known. It is senseless to keep bringing the notion up. The question is simply who has changed his velocity by accelerating? The guy on earth, or the guy on the train?

It is the guy on the train.

The POINT is that once he makes those necessary and proper adjustments to his "measurements" (as you call them) they will AGREE, not DISAGREE, about what is, and what is not, "simultaneous."

THAT'S the point of this example. Nothing else in particular.

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@layman,

You are using the phrase "with respect to the Earth" as if it matters.

If the train were on Mars would you then consider Mars to be motionless?

1 Reply

@layman,

Quote:

The question here is not "who's correct" on a universal scale, i.e., who is ABSOLUTELY moving. That can't be known. It is senseless to keep bringing the notion up.

Didn't you say that time would slow down for the person who was absolutely moving?

This would provide a way for us to absolutely know who was motionless on a universal sense. You simply look at each moving clock until you found the clock that was going the fastest. That would be the motionless clock. The reason this is important is because when we were talking about time dilation, you made it important.

Your statements that the moving clock slows down compared to the motionless clock says that it is both important and knowable.

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@maxdancona,

Quote:

If the train were on Mars would you then consider Mars to be motionless?

If they were all on Mars, and everything else was the same, then, I would treat it the same as I do the earth in this example.

But, how many ******* times do I have to say it before you get it through your head. I am not saying that either Mars, or Earth, is "motionless"

YOu repeatedly TELL me that's what I'm saying when I've told you 50 times that I'm not saying that.

Can we leave the straw men out of it?

1 Reply

@maxdancona,

Didn't you say that time would slow down for the person who was absolutely moving?

When? I have never talked about absolute motion. Only YOU do that, and only YOU won't quit.

No!
No!
N0!
No!
No!

I'm NOT talking about absolutely motion. NO! NO! NO!

I've talked about absolute motion in only on sense, and it is NOT the sense you keep imputing to me. ACCELERATING motion is absolute motion in the sense of being frame independent. That's true even "in SR." I put that in quotes because it is outside the domain of SR, but even Al admits that acceleration is absolute motion, not relative motion.

Get it? Read my post about Newton again.

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@maxdancona,

Didn't you say that time would slow down for the person who was absolutely moving?

When? I have never talked about absolute motion. Only YOU do that, and only YOU won't quit.

No!
No!
N0!
No!
No!

I'm NOT talking about absolutely motion. NO! NO! NO!

Get it? Read my post about Newton again.

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Who's familiar with the conversion? - "In 15 years' ship-time they could reach Andromeda

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