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View Full Version : The roundtrip time of light travel and how it really works!

02-17-12, 09:48 PM
I thank Prometheus for allowing me to take some time off the site. I had a nice vacation and used my time wisely. I constructed a diagram of the preferred frame which shows the round trip time of light travel.

I hope everyone enjoys the pic. Please feel free to play around with different z times using the formula provided. I challenge anybody to find an error.

I think the pic pretty much sums up my theory, but as usual, there are nay-Sayers out there that simply refuse to accept the concept of a preferred frame. By all means, let's talk about it. I'm ready to divulge the secrets of the hidden frame at your request.

http://www.sciforums.com/attachment.php?attachmentid=4522&stc=1&d=1329536887

arfa brane
02-17-12, 10:17 PM
In your diagram the box is moving relative to the source, or the source is moving relative to the box, right?

How do you tell the difference, or isn't there any difference?

02-17-12, 10:19 PM
In your diagram the box is moving relative to the source, or the source is moving relative to the box, right?

How do you tell the difference, or isn't there any difference?

Like stated in the bottom right corner, the source remains at the center of the cube at all times.

arfa brane
02-17-12, 10:25 PM
Like stated in the bottom right corner, the source remains at the center of the cube at all times. Why is the centre of the light sphere at the left of the box in the second figure, then?

02-17-12, 10:26 PM
Why is the centre of the light sphere at the left of the box in the second figure, then?

The red dot is the origin of the light sphere, where the light was emitted at time t=0. The source is the orange dot at the center of the cube at all times.

arfa brane
02-17-12, 10:28 PM
The red dot is the origin of the light sphere, where the light was emitted at time t=0. The source is the orange dot at the center of the cube at all times.So the light sphere hasn't reached the source yet, in the second diagram? Which means the center of the box is moving faster than the light it emitted?

02-17-12, 10:32 PM
So the light sphere hasn't reached the source yet, in the second diagram? Which means the center of the box is moving faster than the light it emitted?

The source emitted light at the center of the cube at t=0. The light sphere expands its radius from the point of origin at the rate of c. The cube is traveling to the right, so the light sphere is a distance away from the source at t=.65 but has only reached the z receiver at that point.

arfa brane
02-17-12, 10:46 PM
The source emitted light at the center of the cube at t=0. Right. The source is initially at the center of the cube, and so is the light sphere, it just has a radius of zero at t = 0.

The light sphere expands its radius from the point of origin at the rate of c. In every direction, or only in a preferred direction?

The cube is traveling to the right, so the light sphere is a distance away from the source at t=.65 but has only reached the z receiver at that point. But that says the light sphere moves as a sphere away from the source in a particular direction (to the left), rather than at c in all directions. How does a light sphere emitted by a source "move" to the left of the source such that the light sphere hasn't yet reached the point it was emitted from? When is the light emitted?

It seems somewhat unphysical. It seems to be saying a source can emit light and move away from the point of emission faster than light.

02-17-12, 10:53 PM
Right. The source is initially at the center of the cube, and so is the light sphere, it just has a radius of zero at t = 0.
In every direction, or only in a preferred direction?

The radius of the light sphere expands at the rate of c in all directions away from the point of origin.

But that says the light sphere moves as a sphere away from the source in a particular direction (to the left), rather than at c in all directions. How does a light sphere emitted by a source "move" to the left of the source such that the light sphere hasn't yet reached the point it was emitted from? When is the light emitted?

The light sphere doesn't move, the light sphere expands its radius from the point of origin at the rate of c in all directions away from the point of origin. The point of origin is incapable of moving, there is nothing at that point, it is simply the point in space that the light source emitted light at t=0. The source has since moved away from that point after t=0, hence the source is no longer at the point of origin nor the center of the light sphere.

It seems somewhat unphysical. It seems to be saying a source can emit light and move away from the point of emission faster than light.

Not faster than light, slower than light. Do you see that the radius of the light sphere in the x direction at .65 is further away from the point of origin at t=.65 than the source is? The light traveled faster away from the point of origin than the source did.

arfa brane
02-17-12, 10:59 PM
Sorry, but what the first diagram shows, is a red dot at the center of a square, which you claim is a source of light. The second diagram shows another source to the left of the first, with an expanded "light sphere", and no details about when it emitted any light.

You've done what you appear to do every time, you've introduced another frame of reference which is not in the diagram initially, in a completely arbitrary manner.

You haven't thought about this as well as you're making out. How does the light get to the left of its point of emission if it expands at c in every direction from that point, and when does it do this?

02-17-12, 11:08 PM
Sorry, but what the first diagram shows, is a red dot at the center of a square, which you claim is a source of light. The second diagram shows another source to the left of the first, with an expanded "light sphere", and no details about when it emitted any light.

In frame 1 there is no red dot, there is simply an orange dot which represents the source centered in the box. The light is emitted at t=0. In frame 2 there is the orange dot at the center of the cube which is the source, and there is a red dot to the left of the source, which is where the source was at t=0 when it emitted light.

You've done what you appear to do every time, you've introduced another frame of reference which is not in the diagram initially, in a completely arbitrary manner.

I am showing how the cube travels in the preferred frame. Do you not understand that there is no other object in the pic? There is a cube in space, with a light source that remains fixed at the center of the cube. There is nothing outside the cube.

You haven't thought about this as well as you're making out. How does the light get to the left of its point of emission if it expands at c in every direction from that point, and when does it do this?

Light travels away from the point of origin in every direction. You can think of it as simply distance from the point of origin because distance is inseparable to time when speaking about light travel, by definition. The sphere represents the distance that light travels away from the point of origin in that specific amount of time.

arfa brane
02-17-12, 11:25 PM
In frame 1 there is no red dot, there is simply an orange dot which represents the source centered in the box. The light is emitted at t=0. In frame 2 there is the orange dot at the center of the cube which is the source, and there is a red dot to the left of the source, which is where the source was at t=0 when it emitted light.The source is at the center of the box in figure 1, when t = 0.
In figure 2, the source isn't at the center any more when t > 0. In fact the light hasn't reached the center of the box yet.

If that's all correct, then the center of the box, which initially is the source, has moved away from itself at > c. Otherwise the light would NOT be to the left of the center of the box. Both figures, taken together, contradict the condition that light moves away from a source at c in all directions.

You can't have it both ways.

02-18-12, 07:29 AM
The source is at the center of the box in figure 1, when t = 0.
In figure 2, the source isn't at the center any more when t > 0. In fact the light hasn't reached the center of the box yet.

I'll repeat it again since you didn't understand it the first time, nor can you read a simple color coding clearly displayed in the pic.

The source remains at the center of the cube at all times. The source is the orange dot.

If that's all correct, then the center of the box, which initially is the source, has moved away from itself at > c. Otherwise the light would NOT be to the left of the center of the box. Both figures, taken together, contradict the condition that light moves away from a source at c in all directions.

You can't have it both ways.

It's not correct. I'll say it again, the orange dot (the color that looks like the fruit that's called an orange which grows on trees, that you peel and eat) is the source, and it remains at the center of the cube at all times.

arfa brane
02-18-12, 02:44 PM
The source remains at the center of the cube at all times. The source is the orange dot.But the light sphere in the second figure is centered on the red dot.

So 1) where is the light sphere that propagated from the orange dot? and 2) when does the red dot appear between figure 1 and figure 2, and when does it emit light?

The center of the box where the orange dot is is supposed to have light propagating at c in all directions from it, according to what you've said. What you have is the orange dot not emitting light, and a second dot to its left emitting light. Your descripton doesn't match the figures.

I realise that pointing this out is going to get me exactly nowhere, because that's where you still are. This is a waste of time.
You've put some diagrams together and explained what they're supposed to be, but the explanation doesn't seem to correspond to the diagrams. The diagram universe is a tricky place.

02-18-12, 04:55 PM
But the light sphere in the second figure is centered on the red dot.

That is because that is the point of origin of the light sphere. That is where the source was at t=0 when it emitted light. The source is no longer there, it moved away from there, but the light continues to expand from where it was emitted, the point of origin (the red dot).

You are confused because all this time you were lead to believe that light spheres travel with the cube, but that is simply impossible, as you can clearly see in my diagram. The light sphere expands in the preferred frame, not in the cube frame. The cube travels in the preferred frame.

AlphaNumeric
02-18-12, 05:46 PM
Posting expressions to the same number of decimal places as your calculator or spreadsheet program displays is a classic sign of someone inexperienced with mathematics or even science in general.

Your pictures never actually demonstrate anything other than the fact you like to write down the same expressions all the time. It's possible to construct mathematical systems which do have preferred frames, where there is an absolute velocity. Doesn't make them right when it comes to physical reality. After all, you don't think relativity is accurate and it's mathematically sound.

The ultimate arbiter is experiment and light (and physics in general) simply doesn't behave as you claim it does. There isn't anything else which needs to be said. Until you can come up with a formalism which incorporates an absolute frame and which can reproduce all of the observed results you're just whining about a universe which exists only within your head.

arfa brane
02-18-12, 08:03 PM
Like stated in the bottom right corner, the source remains at the center of the cube at all times.

The red dot is the origin of the light sphere, where the light was emitted at time t=0.
So you can see there might be confusion about where the light was emitted from.

Unless you want us to believe the source and the origin of the sphere of light have different coordinates.
This cannot be true at t = 0, for instance.

AlphaNumeric
02-19-12, 03:16 AM
I suggest MD reads a thread in the pseudo forum started by a poster called Jack_ , he had similar issues with boxes and spheres and moving emitters. I provided plenty of lengthy explanations of his misunderstandings. However, if MD's mathematics skills are anything to go by I wonder how much of it he'll follow.....

02-19-12, 03:44 PM
I suggest MD reads a thread in the pseudo forum started by a poster called Jack_ , he had similar issues with boxes and spheres and moving emitters. I provided plenty of lengthy explanations of his misunderstandings. However, if MD's mathematics skills are anything to go by I wonder how much of it he'll follow.....

I schooled Jack many moons ago on a different forum under a different name that he used, but he never fully understood what I was saying, nor did he have my equations, simply because they didn't exist at that time.

I just figured out last week how this ties in with round trip time, so nobody knew before that time.

AN, I'm really sorry that you are so stuck on the penmanship that you can't understand the message.

Here's the message once again, since you fail to grasp the magnitude of my discovery:

I am the first person in the history of the world to be able to calculate the motion of a box in the preferred frame using the constancy of the speed of light in that preferred frame, all the while having all numbers in all frames add up properly.

Maybe you don't understand, so I will break it down for you a little more. Nobody has ever been able to make the numbers work without using a bunch of band-aid BS such as length contraction (which has never been proven), time dilation, or the really stupid concept of the relativity of simultaneity. After using all those band-aids to try to get the numbers to add up, Einstein still fails to be able to determine the velocity of the box.

I say again, I am the only person in the history of the world that has EVER been able to know the velocity of the box in the preferred frame, maintain the constancy of the speed of light in the preferred frame, and have all the numbers add up, and I do it all with no band-aids required!

AN, I admire your math skills probably more than anybody, but stop and think what I have done, just for a moment, will you? I have provided you with a diagram of a METHOD to the madness, which has NEVER been done before.

02-19-12, 03:55 PM
So you can see there might be confusion about where the light was emitted from.

Unless you want us to believe the source and the origin of the sphere of light have different coordinates.
This cannot be true at t = 0, for instance.

The light was emitted at t=0 when the source was at the point of origin.

The source is not at the point of origin after t=0.

You have serious problems if you can't understand that.

arfa brane
02-19-12, 05:07 PM
Explain how light propagates at c in all directions from a source that then
moves away from itself at a speed greater than "the origin" of the emitted light sphere.
This sphere is supposed to be moving away from its point of emission (the origin
at t = 0) at the same speed in all directions.

Your diagrams show something else. If you can't see that I don't know what to say.

02-19-12, 05:25 PM
Explain how light propagates at c in all directions from a source that then
moves away from itself at a speed greater than "the origin" of the emitted light sphere.
This sphere is supposed to be moving away from its point of emission (the origin
at t = 0) at the same speed in all directions.

Your diagrams show something else. If you can't see that I don't know what to say.

If you want to fill in subsequent light spheres emitted by the source after t=0 be my guest. That has no bearing on what we are talking about. All you will do is show the wave length and frequency, which has no impact on the outer most light sphere emitted at t=0. ALL other spheres you input from the source at a time after t=0 will be INSIDE the outer most light sphere shown, that was emitted at t=0. You adding in smaller spheres will do nothing other than to show the Doppler affect.

Maybe you think the speed of light is supposed to be relative to the source at all times? Absolutely not. The light travels away from the point of origin and the source travels away from the point of origin as well. The light's motion is relative to the point of origin and so is the source's motion.

arfa brane
02-19-12, 06:15 PM
The outermost light sphere was emitted from the center of your box or cube.
If it expands outward at c in every direction, then figure 2 should have a light
sphere centered on this same point. It doesn't, so your explanation falls over.

You've explained at least 4 times that the sphere of light expands outward at c
in all directions. Of course, in real life, nobody can see this sphere of light except
an external observer. In your second figure the Z detector is "seeing" the leading
wavefront, but not of the light emitted from the center.

The second figure doesn't show a light sphere expanding from the center of the
box, which is what it needs to show if light spheres expand at c in all directions, AND
if light was emitted from that point.

02-19-12, 06:32 PM
The outermost light sphere was emitted from the center of your box or cube.
If it expands outward at c in every direction, then figure 2 should have a light
sphere centered on this same point. It doesn't, so your explanation falls over.

You've explained at least 4 times that the sphere of light expands outward at c
in all directions. Of course, in real life, nobody can see this sphere of light except
an external observer. In your second figure the Z detector is "seeing" the leading
wavefront, but not of the light emitted from the center.

The second figure doesn't show a light sphere expanding from the center of the
box, which is what it needs to show if light spheres expand at c in all directions, AND
if light was emitted from that point.

I have to tell you, arfa brane, you really are as dumb as a box of rocks. You still haven't figured out what the heck is going on.

The box is in motion in the preferred frame, as is the radius of the light sphere as it expands at c. Do you not understand that? Do you not understand that the box is in motion relative to the light sphere???? WTF? :rolleyes:

AlexG
02-19-12, 07:04 PM
There is no preferred frame, except in MD's own little delusional universe.

arfa brane
02-19-12, 07:23 PM
Do you not understand that the box is in motion relative to the light sphere???? WTF?

Do you not understand that you said that light is emitted in all directions from the center of the box? So if it travels at c in every direction from that point the result is a sphere centered on the point OF EMISSION? NOT centered on some other point you've introduced in order to sort those rocks you mentioned?

Can't you see that you're really saying: "Light travels at c, and expands spherically from a source, except if the source is moving".

So does light travel at c or not? How does the center of the box "know" its moving?

James R
02-19-12, 09:25 PM

Your diagram is correct for a frame in which the box is moving to the right. You have correctly determined the speed of the box relative to that frame of reference.

Your diagram does not apply when you go to another frame. In particular, it does not apply in a frame where the box is stationary.

We've already been through this in detail. Please review the following thread, where I walked you through it all in excrutiating detail.

Relativity of simultaneity

You keep making the same mistake over and over again. There is no absolute frame of reference, and you haven't determined any kind of absolute speed. Your thought experiment only determines the speed of the box in the frame you have chosen - which is not absolute.

Repeat the experiment inside the box (i.e. in a frame where the box is stationary) and the light pulse from the centre will hit all sides of the square box simultaneously.

I am the first person in the history of the world to be able to calculate the motion of a box in the preferred frame using the constancy of the speed of light in that preferred frame, all the while having all numbers in all frames add up properly.

There are no preferred frames. You have only managed to determine the motion of the box in your favorite frame, which need not be absolutely stationary.

It is quite clear that you still don't understand what a reference frame is. Please review the thread I linked above.

Oh, and there's nothing worth parading your ego about here. This is high school physics. Also, there's no relativity in your example, because you only consider one reference frame. I know you imagine this somehow disproves Einstein's relativity, but in fact it doesn't even begin to address the relevant issues.

Nobody has ever been able to make the numbers work without using a bunch of band-aid BS such as length contraction (which has never been proven), time dilation, or the really stupid concept of the relativity of simultaneity. After using all those band-aids to try to get the numbers to add up, Einstein still fails to be able to determine the velocity of the box.

Your numbers work just fine in the "embankment frame". They only apply to that frame. Your continuing problem is that you don't believe any other frames are possible.

Since this thread is a useless repeat, I will close it.