Would Religion still continue if....

[Franko]

Stimpson: (A-Theist)
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.

Yes, yes Stimpy, I realize that it is “bad form” to tell a priest that he doesn’t know what he is talking about, but you must remember I am NOT a follower of your religion. Your Dogma is not so sacred to me.

You are wrong. It is that simple.

Well, at least it would be if Solipsism were true. (but don’t give up hope yet!)

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.

A = First Asteroid ship
B = Second Asteroid ship
C = Earth

Right, so from the POV of someone one Earth (C) they would see the two ships (A & B) moving away from the Earth (C) at 210,000 km/sec, and moving away from each other at 420,000 km/sec. In the meantime, the two ships separating at a rate FASTER THAN THE SPEED OF LIGHT (420,000 kms), would STILL be able to communicate AT THE SPEED OF LIGHT (300,000 kms).

Seems a bit odd … that’s all … seems to contradict what you are actually claiming.

 

[Tricky]

Yes, yes Stimpy, I realize that it is “bad form” to tell a priest that he doesn’t know what he is talking about, but you must remember I am NOT a follower of your religion. Your Dogma is not so sacred to me.



Well, at least it would be if Solipsism were true. (but don’t give up hope yet!)



A = First Asteroid ship
B = Second Asteroid ship
C = Earth

Right, so from the POV of someone one Earth (C) they would see the two ships (A & B) moving away from the Earth (C) at 210,000 km/sec, and moving away from each other at 420,000 km/sec. In the meantime, the two ships separating at a rate FASTER THAN THE SPEED OF LIGHT (420,000 kms), would STILL be able to communicate AT THE SPEED OF LIGHT (300,000 kms).

Seems a bit odd … that’s all … seems to contradict what you are actually claiming.

It does seem counterintuitive. Maybe that's why Newton, genius that he was, couldn't figure it out.

As I see it (and I am by no means in the league of some of these guys), two ships can never be moving apart at the speed of light, although technically they could approach the speed of light. However, light always moves at the speed of light, so communication is possible since the light is always faster that the relative motion of the ships.

 

[Upchurch]

It looks like you understand relativity about as well as you understand Determinism and “free will”.

Never expected a compliment out of you, Franko. Thanks.

Let's do some math!

Problem 1:

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. [v1 = 0.5c, from the asteroid] 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) [v2 = 0.7c, I'm guessing?, from the Earth] 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?

u = (v1 + v2) / (1 + (v1 v2) / c^2)
u = (0.5c + 0.7c) / (1 + (0.5c 0.7c) / c^2)
u = (1.2c) / (2.2)
u = 0.55c (approximately)

Significantly less than 1.2c, actually.

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])?

c ~ 3 x 10^5 km/s
u = 0.55c = 1.65 x 10^5 km/s

u < c

If not, why not?

Because of the calculations given above.

For all we know the Earth itself is already moving at 0.7 x C?

Relative to the asteroid, as mentioned, v2 = 0.7c. That's accounted for in the calculation.

Without a common point of reference, I am not sure what “speed/velocity” even means?

No problem. both v1 (the speed of the rocket) and v2 (the speed of the Earth) is relative to asteroid.

Note: part of Relativity is that, in inertial reference frames, it's equally valid to say that the Earth is moving away from the asteroid as it is to say that the asteroid is moving away from the Earth. Same with the rocket and the Asteroid. And the rocket in the Earth.

To sum up, velocity between the following reference frames:
Earth/asteroid = 0.7c
asteroid/rocket = 0.5c
rocket/Earth = 0.55c

Problem 2:

And I am saying that if you have one ship moving away from the Earth at 210,000 km/sec [v2 = 0.7c] then in 10 seconds [t1 = 10 s, from what reference frame?] the ship will be 2.1 million km [l1 = 2.1 x 10^6 km, from what reference frame?] 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 [v3 = 4.2 x 10^5 km/s, from the Earth] then either they are moving faster than the speed of light, or they are not.

Not enough information. You haven't said from what inertial reference frames that t1 and l1 were measured. From the Earth? The ship?

Also, v3 is theoretically impossible for a macroscopic ship with mass.

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.

Imply nothing, I'll flat out tell you that it is physically impossible for any two objects with mass to move away or towards each other at a velocity equaly or grater than 3 x 10^5 km/s. Further, I'll flat out tell you that it is physically impossible for any two photons to move towards or away from each other with any other velocity other than 3 x 10^5 km/s.

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.

Have you read through any of my calcualtions? I'm clearly not saying anything of the sort. Please, review my calculations again and tell me where I posit or conclude that light moves at anything other than 3 x 10^8 m/s.

 

[ScottDYelich]

hahahahahahahahahahha

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 ?

franko... puh-leeeeeze....

I can't take it anymore. I'm laughing so hard my stomach aches.

Yes, something smells fishy... but I the smell is slightly stronger in your relative perspective.

Scott

 

[Franko]

Latimer:
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.

There’s a problem with that.

Look … from Earth, I measure that each ship is moving away from me at 210,000 kms, and since they are moving in opposite directions then it is pretty easy to figure out that they are moving away from each other at twice that rate.

10 seconds after I make my measurement I see that the two ships have gotten 4.2 million km farther apart.

But not according to you (and Upchurch). According to your interpretation even though from the Earth I perceive that the two ships are 4.2 million km farther apart you seem to be saying that they will only be 2.8 km farther apart (300,000 kms x 0.94c = 282,000 kms). In other words, You are saying that even though I observe each ship traveling away at 0.7 they are really only traveling .047 (0.94/2).

But by that same Logic photons leaving the Sun should be taking twice as long to get to the Earth then what they actually do. In other words, your explanation is contrary to observed reality!

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.

Forget the time dilation effects on the ships. Assume you re doing all of your observations from Earth where there is no relativistic effects. If you know both ships speed, then you can calculate the rate at which they are moving away from you – km per sec.

My problem is that you are trying to say that the ships are moving away from the Earth at one speed, but away from each other at a different speed. What you are claiming is logically contradictory, and there is no evidence to support it.

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.

Right! Theoretically if an objective was moving away from you faster than the speed of light it would simply vanish. The light from the object couldn’t reach you because the object itself would be moving FASTER than the light streaming back towards you.

But that is the very point I was raising with this example. Even though the two ships would clearly be moving away from the Earth faster than the speed of light (from an observer on Earth’s POV), it would seem the two ships would still be able to communicate with each other but only by relaying the signal through Earth first.

Franko:
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.

Latimer:
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.

Yeah, but like I said, even though no time would pass relative to an observer traveling at the speed of light, he would have still covered DISTANCE. And DISTANCE is really what we are talking about.

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. Meaning photons leaving the sun on opposite sides would only travel at a TOTAL combined speed of 1.0xC. 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.

 

[Upchurch]

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 …

Let's think about this for a second. You can't understand how the signal could reach from one ship to another because of a compined velocity of 1.4c (as you claim), but you can see the signal transversing that same distance using Earth as an intermediary because each leg is only increasing at 0.7c?

So, what if we sent to messages out. One is sent ship to ship and the other is via Earth. Presumably the ship to ship message would reach Earth at the same time the via Earth message got there. Further, let's assume that Earth can relay the message immediately. So, the ship to ship message and the via Earth message leave the Earth at the same time and make the final leg out to the other ship. They seem to be traveling neck and neck the whole way. Why is it that you think the ship to ship message won't make it but the via Earth message will?

 

[ScottDYelich]

franko

Again, isn't it tweaky?!?!


Keep smiling, [/B]

simple experiment... for franko.

two clocks... set the same.
one stays on the surface of the planet,
one goes up in the space shuttle (or in a
hot air balloon) ...

when they come back together, they will have
(ever so slightly) different times.


FRANKO-- they are made of atoms, atoms obey TLOP.
yet, they are different! who made that decision
to make them different!!!!!!!!!!!



Scott

 

[Franko]

Franko:
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. [v1 = 0.5c, from the asteroid] 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) [v2 = 0.7c, I'm guessing?, from the Earth] 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?

Upchurch:
u = (v1 + v2) / (1 + (v1 v2) / c^2)
u = (0.5c + 0.7c) / (1 + (0.5c 0.7c) / c^2)
u = (1.2c) / (2.2)
u = 0.55c (approximately)

Significantly less than 1.2c, actually.

So for any alien civilization trying to launch a spaceship their max speed is limited by the relative motion of their planet in relationship to Earth???

Suppose that there was some calamity on the Asteroid ship, and all of the adults were killed off. But since it is a self-sufficient colony ship built for a long journey in 100 years the little planet is repopulated, but now, none of the inhabitants even remembers the Earth. As far as they know, they are people just like us, living on their own little planet in the big Universe. They have no idea what or where the “Earth” is.

So you are saying that these people are going to launch their rocket, and it’s going to be a complete mystery why it isn’t going the speed that it is supposed to go?

From those people’s POV (on the asteroid ship) are they still traveling at 0.7 x C? Why aren’t they just another planet like the Earth? … or should I say, how do you know that the Earth isn’t already moving 0.7 x C in relationship to some other unknown planet, thus limiting our maximum speed?

 

[Upchurch]

So for any alien civilization trying to launch a spaceship their max speed is limited by the relative motion of their planet in relationship to Earth???

Nope. Assuming that they are coming to Earth, their maximum speed is limited by the speed of light. If they are going anywhere else, how fast we see them getting there is limited by their relative motion to the Earth.

Suppose that there was some calamity on the Asteroid ship, and all of the adults were killed off. But since it is a self-sufficient colony ship built for a long journey in 100 years the little planet is repopulated, but now, none of the inhabitants even remembers the Earth. As far as they know, they are people just like us, living on their own little planet in the big Universe. They have no idea what or where the “Earth” is.

How sad. They should have invested in some books or movies.

So you are saying that these people are going to launch their rocket, and it’s going to be a complete mystery why it isn’t going the speed that it is supposed to go?

From their frame of reference, they're only limited by the speed of light (and how fast the rocket can go, of course)

From those people’s POV (on the asteroid ship) are they still traveling at 0.7 x C?

They are depending on what they're measuring that against.

Why aren’t they just another planet like the Earth? … or should I say, how do you know that the Earth isn’t already moving 0.7 x C in relationship to some other unknown planet, thus limiting our maximum speed?

uh-oh. I see a light coming on. You're getting closer to understanding.

See, the big thing with Relativity is that there is no absolute reference frame. If one ways that they are traveling at a certain speed, they are saying it in reference to another object. When I'm driving my car and I'm traveling 25 mph, that's in relation to the road. When a pilot is fly a plane and going 800 mph, that's in relation to the Earth below it. In the examples given above, the velocities were almost always given in relation to another object (or if they were, I asked.) So, if an object is moving away from the Earth at 0.7c, it is just as valid to say that the Earth is moving away from the objet at 0.7c. There is no way to distinguish which object is actually moving. In fact, the question is meaningless. The only thing that can be said is that the Earth and object are changing distance between them. How quickly depends on whose point of view you're asking from.

 

[Franko]

Okay, Upchurch – just a brief momentary tangent …

Suppose We have the same scenario, except lets say that we have Two planets directly opposite each other with Earth in the center, and the two planets are Both Exactly 7 Light years away. One to the "East" and one to the "West".

B-------------A-------------C

A= Earth, B = Planet 1 (7 LY away), C = planet 2 (7 LY away)

So now … when we launch our two spaceships traveling at 0.7 x the speed of Light (C) … how long until they should reach the two planets in opposite directions? (from the POV of an observer on Earth). Just round to the closest number of years.

 

[evildave]

Ten years.

Except from Earth, the event of reaching the planets will actually be closer to 17 years away, given the lag in signal (propagating at the speed of light) reaching the Earth from the space craft reaching their respective destinations.

Further complicating matters, we're not counting the time to accelerate to their top speed, nor time to decelerate. The theoretical "top speed" would only be for the cruising (no acceleration) portion of the trip. Factor in acceleration at tolerable G loads.

That is, if you're going to pay attention to physics at all, and not assume silly things, like "instant acceleration".

But hey, we're dealing with Franko.

 

[LucyR]

Except from Earth, the event of reaching the planets will actually be closer to 17 years away, given the lag in signal (propagating at the speed of light) reaching the Earth from the space craft reaching their respective destinations.

No. The implicit assumption (at least I hope this is Franco's thinking) is that an observer on Planet B has a clock which is perfectly synchronized with clocks belonging to observers on Earth and Planet A. They can compare notes at their leisure to determine the trip time.


Further complicating matters, we're not counting the time to accelerate to their top speed, nor time to decelerate. The theoretical "top speed" would only be for the cruising (no acceleration) portion of the trip. Factor in acceleration at tolerable G loads.


I hope Franco's reply would be: 'I modify my question as follows: let's assume a ship traveling at constant velocity passes Earth and at some later time passes Planet A. At the same time as the ship passes Earth another ship passes in the opposite direction on its way to Planet B. What would be the trip time as determined by observers in the common reference frame of Earth, and Planets A and B?'

 

[evildave]

If, for instance the signal was sent when the rockets were at their cruising speed, halfway to their respective destinations, the signal would not reach the opposite rocket in a timely manner, even if re-broadcast from the earth. It had to go all of the 3.5 light years to get to the earth, then 3.5 light years to get to where the receiving rocket WAS when the sender broadcast the original message (that's seven years, so far), and additional time to reach the target rocket at its new position SEVEN years after the signal was sent (already settled in at the other planet). Even if the Earth was used to rebroadcast, it would not reach the other rocket before it reached its destination from that point.

The big doppler shift of the signals involved should be yet another big clue as to what's happening to them.


All of this ignoring (of course) the insignificant details that things don't tend to move in perfectly straight lines in space (there's always some gravity around), and that all of the stars would have shifted many millions of miles in the intervening time, and that the planets would have gone around their respective stars several times while we played around with radios that had a broad enough bandwidth to discriminate a signal that was phase-shifting like these would.


Another fun bit of thought is: if one space ship left 20 years ago, turned around, accelerated, and began broadcasting at .7c, and the other one turned on their radio to receive it while flying (more or less) toward the first one at 0.7c, with a net closing rate of 1.4c, the second ship would receive the original (doppler distorted) signal backwards.

 

[LucyR]

evildave,

With respect, I do not believe that anything you have said in your most recent post is relevant.

If I understand Franco correctly the issue he is having trouble with is the failure of simultaneity, which is a consequence of a universe in which the speed of light is absolute and space and time are relative. This is of course contrary to the Newtonian paradigm in which the opposite is true, and which lay people take for granted. Teaching him the concepts of special relativity will be made immeasurably more difficult if you insist on dishing up multiple red herrings.

 

[evildave]

Lucy, with respect, I believe you give Franko far too much credit. And the least you can do is spell his name right, if you're going to jump to his defense and try to educate him.

Several of his preceeding posts had something very much to do with sending signals between the space ships. I'm just giving out some more fun ones to do with signals, and how they behave when antennae are travelling relative to them.

We can also point out that the stars will be sort of purplish when viewed from the front window of the space ships, and redish with viewed from the rear window.

Not that you'd want to view anything through a front-facing window at these speeds.

 

[c4ts]

Clearly, the earth is flat, and the heavens revolves around it in a prerfect sphere. Einstein, and all those other fools who say otherwise, can take a hike. For, if the heavens did not rotate around the Earth, then why do they shift their positions every night as the sun rises and falls. Maybe they are launched on rockets and fall to the ground from the sky? Haha! No, that is IMPOSSIBLE! You can't launch stars on rocket ships! Look how the moon and sun get BIGGER when they reach the horizon! That's VAPORS from the EARTH making them look bigger, like a superfreak bacterioid under a microscope! They can't possibly be getting any CLOSER! They would have to be launched in a funny baloon shaped horshoe, and we all know rockets follow parabolas, not horshoes, not baloons!

I don't care about no sugar fried honeybuns mathematics, Einstein and his communist nazi parade are WRONG. Period. End of story. Case closed. THE HEAVENS REVOLVE AROUND THE DISK OF THE EARTH BECAUSE THEY ARE SPHERICAL! All you commie nazis can go back to your mud huts in Iraq.

 

[LucyR]

evildave,

Well, I could be wrong but he seems to have the idea that the concept of relativity, as defined by Einstein, is an atheist plot designed to pull the wool over his eyes. His questions are couched in such a way as to suggest that he's trying to force the atheist posters on this board to admit it. If we're nasty to him it'll only reinforce his prejudice.

What I would like to do is start with the empirical observation that c is constant independent of reference frame, and carry on from there. We can explain to him the history of the theory: the failure of the Michelson-Morley experiment, and the observation that the form of the Maxwell equations is not invariant when transforming between reference frames in the Newtonian universe, and the significance thereof. We can present the Lorentz transformation, and describe time dilation and length contraction, and also obtain the expression for the composition of velocities. We can even derive E = mc^2! Perhaps that'll impress him.

My point is that it should be possible to convince him of the validity of SR, if we take things step by step.

PS thanks for correcting my spelling - that was silly of me.

 

[MRC_Hans]

LucyR: That is very nice of you and you might try to address it that way. But I'm afraid the core of the problem is that Franko does not want to understand. His agenda is not to gain new understanding, but to gain yeat another opportunity to yell at people. He feels he is making "A-THeists" look foolish when they attempt to explain and fail, because he refuses to understand. And in a way he is right.

Hans

 

[c4ts]

But if you did that, you will find out that they were WRONG! For it says in the Almagest

In addition to the above, it would also be useful to discuss the problems of at which, in general, it is possible for eliptic syzgies to occur, so that, once we have determined a single example of a syzygy, we need not apply the limits to every succeeding syzygy in turn, but only those which are seperated by an interval of months at which it is possible for an eclipse to occur.

Ptolemy, 6:5

 

[LucyR]

Hans,

Well, I've just had a cup of coffee and feel very positive about things. It won't last.

The thing is I hadn't thought about SR for a long time, and I had forgotten how cool it was. I just wanted the opportunity to talk about it, dammit!