Upchurch
Papa Funkosophy
There was an Amish community near where I grew up. There was an extremely good Amish cabnet maker who got permission to use a diesel engine and system of belts to power his power tools. Plus, they had a phone in case of emergency. Also, they would give their non-Amish neighbors ice cream to put in their freezer and then come over on hot days to help them eat it.whitefork said:
There are theological restrictions and then there are theological restrictions. The Amish I know knew when it was okay to bend the rules to exist in the modern world. Aparently, so do the LD's
Right, but all you are really saying there is that the photons “themselves” don’t experience the passage of any Time as they Travel. (Is that supposed to be a surprising revelation?)
Ohh, I understand what it means just fine. Here’s the thing.
The Two ships are separating at 1.4 x C, and they are still able to communicate. You don’t see a contradiction there Upchimp? Here it is again …
Suppose that at some point in the future Humans are capable of building a spacecraft that can travel of 70% the speed of Light. But imagine that this is a spacecraft built to send Human colonists to another planet, so they build this craft from a large rocky asteroid captured from the solar system.
Now suppose that they build Two of these “spacecraft” – both capable of traveling 70% the speed of light …
… and they send them off in opposite directions. From the POV of the crew on either of these crafts they are standing on a “stationary planetary body” (like the Earth). But since BOTH ships are traveling away from the Earth at 70% the speed of light, wouldn’t they being traveling at 140% the speed of light away from each other? In other words from a person on one of the asteroids, wouldn’t it appear that the other asteroid was moving away from him at a speed beyond what is “allowable” by General Relativity?
Or think of it this way … suppose you have two flashlights, and you “glue” the back ends together so that the beams of lights are shining in opposite directions. From the “POV” of the photons in one beam, aren’t the photons in the opposite beam moving away at twice the speed of light?
I thought that according to GR Nothing could move faster than the speed of light relative to any other object? And if information can’t travel faster than the speed of light, then how come the one ship could relay a signal back to the earth, and then the earth could relay the signal on to the second ship? You just acknowledged that the ships would be separating faster than the speed of light, yet they are still able to communicate?
The Two ships are separating at 1.4 x C, and they are still able to communicate. You don’t see a contradiction there Upchimp?
Either you can explain it, or you can’t “logic-boy”.
Are you trying to say that Einstein questions are off limit on this forum? You seem awfully touchy on this subject whitehead. If you don’t have anything to add to this discussion perhaps you should run along to BANTER?
Upchurch
Papa Funkosophy
No need to repeat yourself, I saw it the first time. I showed you that they are not seperating at 1.4c but at 0.94c. Do I need to say that in big bold capitalized letters as well in order for you to see it? I have no problem pulling out the size tags too.Franko said:
According to classical Newtonian physics, sure. But classical Newtonian physics are wrong, especially at near light speeds.
Do you think Einstein was incorrect about GR, then?
Franko, I have said no such thing. You're the one insisting that they are traveling faster than the speed of light using antique calculation methods. Why aren't you using Newtonian instead of Relativistic mechanics when it is clearly not applicable in this case?
Franko said:
Franko, you aren't listening.
From a point of view of Earth, each ship will be traveling away at .7c.
Yet, mindbendingly, they will *not* be traveling away from each other at 1.4c You are using Newtonian physics precisely where Newton breaks down.
As the math showed above, from the point of view of each ship, they will be travelling away from each other at about .94c. And they will *never* get to 1c, regardless of how much thrust and speed each uses. Both can be at 98 percent of the speed of light, heading in opposite directions, yet, to each other, they *still* won't be moving away from each other at 1c. The c-squared part of the equation prevents it.
It isn't easy to grasp. (How can you be going .7c and .94c at the same time?) But it's the way things work, and has been *very* verified. Hopefully I am explaining it correctly; and, all out there, *please* correct me if my model is incorrectly explaining it. (More numbers a good thing!)
Since it defies common sense and more 'down to earth' logic, does that mean Einstein is about to be thrown into the LG's QM scrap heap as well?
Keep smiling,
Jonathan
-Less Typing! More Home Improvement! (Whip Cracking Sound)-
Upchurch
Papa Funkosophy
Franko said:
In the man's own words (equation format modified for the forum, but notation maintained):
edited to add: there are more pertenent quotes I would like to use, but the notation is very not forum board friendly.
In the form I used earlier,
u = V
v = v
v' = w
c = c
Basically, the same formula I used above. If you want a first-source explination, read Einstein himself. I'm using his theories in my computation. Do you see an error?
MRC_Hans
Penultimate Amazing
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Actually it would be more like: You are unable to understand it.Franko said:
I have even shown how it works at more comprehensible speeds (the two ships at sea). You still dont understand it. No need to be ashamed of that, lots of people dont. Just dont blame others for your lack of understanding.
Hans
Right, so according to YOU streams of photons aren’t actually leaving the Sun at the speed of light, but at only HALF the speed of light. The reason they are only traveling 0.5 x C is because two rays traveling in opposite directions can’t exceed the (total) Speed of light, and since photons are constantly leaving the Sun in both directions they are all traveling at 0.5 x C.
But if that is True, then how comes it only takes the photons 8.33 minutes to get to Earth instead of 16.667 minutes???
Look … if the two ships are moving away from the Earth in opposite directions at 210,000 km/sec, then they are moving away from each other at 420,000 km/sec. If you want to claim that this is wrong, then explain why light traveling from the Sun travels at “full speed” and gets here in only 8 minutes. Or are you saying that this observation (8 minutes) is incorrect? Are you claiming that photons are not traveling off in the opposite direction from Earth at the same rate – analogous to the two spaceships in my example?
Because I observe that light from the Sun reaches us in 8.33 minutes which gives light a speed of 300,000 km/sec. Since I know that a planet on the opposite side of the Sun would also receive the light in 8.333 minutes it is safe to assume that the two streams of photons are moving apart from each other at twice the speed of light.
Similarly, two spaceships launched from the Earth, traveling at a speed of 0.7 x C (210,000 km/sec) in opposite directions will be separating (as measured from Earth) at a rate of 420,000 km/sec FASTER THAN THE SPEED OF LIGHT. Never-the-less, I see nothing that would stop the one ship from radioing back to Earth (which it can still do traveling only 0.7 x C), and then the Earth relaying that signal on to the second ship (which it can do since that ship is also at 0.7 x C). In other words, we’d have two ships moving apart at a speed greater than the speed of light (1.4 x C), yet they would still be able to communicate with each other (at the speed of light (1.0 x C)). Something smells fishy …
Latimer,
How you doing, my Man?
Okay, Latimer, I understand what you are saying.
Lets pretend that there is just one ship heading away from the Earth at 0.7 x C (210,000 km/sec). In 10 seconds it gets 2.1 million kilometers farther away from the Earth correct?
Okay, now suppose that on an alien planet far away from Earth some aliens just happen to be launching their own spaceship, and by random chance it happens to be traveling in the precise opposite direction of our ship at 210,000 km/sec. We don’t know about their ship, and they don’t know about ours.
Isn’t our ship, and their ship moving away from each other at 420,000 km/sec?
In 1 minute you could take their distances, and divide by Time, and you would get their speed ... correct?
If that is True, then how is it that photons from the Sun reach us in only 8.333 minutes instead of 16.667 minutes? Aren’t photons streaming off the Sun in BOTH directions, and according to your interpretation of GR/SR shouldn’t that mean that the relative speed between the two photons in opposite directions is only 1.0 x C total?
Einstein didn’t “kill” Newton, he just modified his algorithm.
How you doing, my Man?
Okay, Latimer, I understand what you are saying.
Lets pretend that there is just one ship heading away from the Earth at 0.7 x C (210,000 km/sec). In 10 seconds it gets 2.1 million kilometers farther away from the Earth correct?
Okay, now suppose that on an alien planet far away from Earth some aliens just happen to be launching their own spaceship, and by random chance it happens to be traveling in the precise opposite direction of our ship at 210,000 km/sec. We don’t know about their ship, and they don’t know about ours.
Isn’t our ship, and their ship moving away from each other at 420,000 km/sec?
In 1 minute you could take their distances, and divide by Time, and you would get their speed ... correct?
If that is True, then how is it that photons from the Sun reach us in only 8.333 minutes instead of 16.667 minutes? Aren’t photons streaming off the Sun in BOTH directions, and according to your interpretation of GR/SR shouldn’t that mean that the relative speed between the two photons in opposite directions is only 1.0 x C total?
Einstein didn’t “kill” Newton, he just modified his algorithm.
Upchurch
Papa Funkosophy
It really bugs you, doesn't it?
One of the men you preport to admire and respect said something that is hard to conceptualize in context of the everyday world. Worse, it looks like he was absolutely correct.
How does one rationalize something as bizare as something having one speed no matter how one is traveling? Condider a man in a spaceship. He turns on the spaceship's headlights. From the spaceship's frame of reference, the light beams shoot out in front of the ship at 1.0c. But from a guy sitting on the ground watching ths ship go buy at 0.7c, the headlights are still going out at only 1.0c. Doesn't make sense, does it?
But it does make sense. Einstein looked at the situation and he figured it out. It wasn't easy. If it had been someone else would have figured it out long before.
If you respect the man, like you say, learn what it is that he actual said and did. I'm not the one that's saying that the ships move apart at 0.94c, Einstein is. I'm just applying his work to the situation.
One of the men you preport to admire and respect said something that is hard to conceptualize in context of the everyday world. Worse, it looks like he was absolutely correct.
How does one rationalize something as bizare as something having one speed no matter how one is traveling? Condider a man in a spaceship. He turns on the spaceship's headlights. From the spaceship's frame of reference, the light beams shoot out in front of the ship at 1.0c. But from a guy sitting on the ground watching ths ship go buy at 0.7c, the headlights are still going out at only 1.0c. Doesn't make sense, does it?
But it does make sense. Einstein looked at the situation and he figured it out. It wasn't easy. If it had been someone else would have figured it out long before.
If you respect the man, like you say, learn what it is that he actual said and did. I'm not the one that's saying that the ships move apart at 0.94c, Einstein is. I'm just applying his work to the situation.
Franko said:
Home improving (and I *suck* at it.) What doesn't kill me makes me stronger, right?
Nope. The frame of reference applies to those two ships. Even though each is moving away from their planet at .7c, when they become aware of each other, they would still be relatively moving at .94c.
Remarkable, isn't it?
And, once again to the crowd, if I am incorrectly explaining it, PLEASE correct me.
Nope. Because their velocities are near-relativistic, their distance would depend on their frames of reference. Even though they are moving from their planets at .7c, they would *still* be moving away from each other at .94c. They would measure their distance from each other and it would reflect the .94c velocity, *not* the 1.4c velocity.
It is, like I said above, quite mind-bending.
Actually, it even gets worse than that. Photons travel at the speed of light, yet, if you were magically riding on a photon traveling from the sun to the Earth, and then somehow measured a photon being released on the opposuite side of the sun, from your point of view, it would *still* travel at *precisely* 1c. And its distance from you would remain as such. 8 minutes later you'd splash into the Earth; and the photon you were observing would still be moving away from you as if it were going 1c and you were 'standing still.'.
Do remember, when we are looking at things, too, that the Earth and our Solar System are whipping around with some good relativistic speed of its own: we have no *fixed* point of reference either. But no matter our frames of reference; if you start slower than c, you'll never get to c, and no one will perceive you at getting to c, either. Twisty, twisty, this Universe of ours.
Rather significantly.
Probably a good thing Newton 'left' before such a modification took place; I understand he was quite cranky about his math... Keep smiling,
-The Hammer is NOT used on your own hand. That lesson has been taught to me TWICE in the last 48 hours...-
Okay, lets walk through it sloooow …
You have two ships flying away from the Earth at 210,000 km/sec (0.7 x C). Starting at time-0, if you wait 10 seconds, and measure their distance from the Earth, each ship is 2.1 million miles farther away, and 4.2 million miles farther from the other. Correct? Or are you claiming that even though the ships are getting farther from the Earth at one rate they are getting farther from each other at another different rate?
Now neither of the ships would be able to perceive each other directly, would they? So they couldn’t make a direct measurement … ?
According to Einstein Time essentially stands still if you happen to be traveling at the speed of light. In other words, if you shoot a photon off towards a planet that is 100 light years away, then even though the photon takes 100 years to get there from Your POV, from the POV of the photon (if you could have ridden along), the photon arrives there instantaneously. From the photon’s ‘POV” no time has passed. But just because no Time passes doesn’t mean that no distance was traveled.
If we have no *fixed* point of reference … then how do you know that we (the entire universe) isn’t already traveling at the speed of light?
Speed, velocity and movement only have relevance when in relation to a point of reference. In other words, imagine you were floating alone in a complete void with no fixed points of reference. How would you know if you were “stationary”, or moving along at 100,000 mph?
You wouldn’t know. The only possible way for you to tell would be if there was at least one fixed point of reference. That way you could perceive your motion by observing your positions change relative to the fixed point.
Upchurch
Papa Funkosophy
In fact, at 0.7c, the distance between the two ships, from the point of view of the Earth, would be roughly 54.8% the distance seen by the two ships.Latimer said:
(I think I have that right. I may have that turned around...)
Upchurch
Papa Funkosophy
Aside: Please be aware that SR is not defined for objects traveling at the speed of light (1.0c), only for objects below the speed of light. All this talk about what a photon "sees" is just conjecture based on an extrapolation of SR. In other words, it's a guess based on a limit.
How is Your inability to explain what You believe, My problem?
It looks like you understand relativity about as well as you understand Determinism and “free will”.
Or imagine that you have some people living on a small little planet. They launch a rocket into space which can travel 0.5 x C. Now … suppose that the little planets is actually one of the asteroid ships, and suppose that they launch the rocket away from Earth (the same direction they were traveling) The rocket would only be flying away –relative to the asteroid – at 0.5 x C, but relative to the Earth wouldn’t that little rocket be moving at 1.2 x C? In other words wouldn’t the mini rocket being moving away from the Earth at 210,000 km/sec + 150,000 km/sec (360,000 km/sec [greater than C])? If not, why not? For all we know the Earth itself is already moving at 0.7 x C? Without a common point of reference, I am not sure what “speed/velocity” even means?
Yeah, but like the wheel it seems so simple after you see it. You wonder why no one realized it sooner?
And I am saying that if you have one ship moving away from the Earth at 210,000 km/sec then in 10 seconds the ship will be 2.1 million km farther away. If you have two of these ships and they are moving in opposite directions at this speed then after 10 seconds they will be 4.2 million km apart as measured from Earth.
If I am on the Earth and I am tracking the two ships positions and I measure two ships moving apart at 420,000 km/sec then either they are moving faster than the speed of light, or they are not.
You seem to be implying that it is physically impossible for ANY two objects (even photons) to move away from each other at a rate greater than 300,000 km/sec. Essentially you are claiming that the speed of light is only half what everyone thinks it is. I guess someone should tell Hawking there are going to be a lot more “black holes” then he thought.
Stimpson J. Cat
Graduate Poster
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Franko,
You are making my head hurt. Your ignorance of basic relativity is understandable, but your inability to understand it, even when it is carefully explained to you, is just sad. And the fact that you would presume to tell somebody who has studied the subject extensively, and has a degree in Physics, that he is wrong about it, is just mind-numbingly stupid.
You are wrong. It is that simple. If you have three objects, A, B, and C, then it is possible for the relative velocity of any two of them to be more than c, from the point of view of the third. But the relative velocity of any two of them, as measured from either of their own reference frames, will always be less than c. That is what Special Relativity says. Deal with it.
Dr. Stupid
You are making my head hurt. Your ignorance of basic relativity is understandable, but your inability to understand it, even when it is carefully explained to you, is just sad. And the fact that you would presume to tell somebody who has studied the subject extensively, and has a degree in Physics, that he is wrong about it, is just mind-numbingly stupid.
You are wrong. It is that simple. If you have three objects, A, B, and C, then it is possible for the relative velocity of any two of them to be more than c, from the point of view of the third. But the relative velocity of any two of them, as measured from either of their own reference frames, will always be less than c. That is what Special Relativity says. Deal with it.
Dr. Stupid
Franko said:
That's it, exactly. Although they are leaving the Earth at one rate, relative to the frame of reference of the Earth, they are getting farther away from each other at a different rate, relative to the frame of reference of each other. And we have experimental verification of this.
In your example, although they would each be moving away from the Earth at .7c, they would be moving away from each other at .94c.
It's even worse than THAT. Because the ten seconds they thrust isn't constant either. 10 seconds on Earth would NOT equal ten seconds on each rocket. Time isn't the constant here. Light is.
And NOW you are hitting some Quantunm theory after all. Since, theoretically, their ability to *perceive* the other ship (the information about where it is) travels at the speed of light, you'll see it where it WAS when the light gets to you. So, again, at relativistic velocities, things get very funky.
Very good. But, as you can see, time is the flexible ingredient. Did no time pass at all, or did 100 years pass? The answer is both! It was dependent on the frame of reference. So, again, even time is not the constant. The *only* constant is the speed of light.
Well, actually, it *is.* Or, at least a very good chunk of the speed of light. We can see those velocities in the light everywhere we observe.
You wouldn't. Worse than that: How could you perceive *time* moving either? How would you measure it? That's what relativity is all about; that you are always measuring relative to something else. We can measure in our daily lives because of a very wide frame of reference we all live in. Yet Voyager, which has been travelling for years at high velodcity, is now in a *slightly* different frame of reference. Atomic clocks on board, specifically matched with atomic clocks here to several decimal places, are now slightly out of whack with each other because of Voyager's velocity relative to Earth. The *only* constant seems to be the speed of light.
Again, isn't it tweaky?!?!
Yes. And the scary thing is what Einstein discovered: There is no fixed point to measure! Time dilates, mass changes, energy converts. The only fixed *thing* seems to be the speed of light; regardless of your frame of reference.
HOPEFULLY I got all that right.
Keep smiling,