Relativity And Simple Algebra

[Moronium]

PS. Thanks for admitting you were lying or are you going to deny that now.

 

 

Well, you've just demonstrated yet another area where you are seriously lacking in basic ability, eh, Ralf?  To wit:  reading comprehension.

 

But of course we already knew that.

 

You can't even read you OWN posts.   Here's what you said:

 

:

OK now you're just outright lying. Never did I say or imply the number .17c.

 

 

 

That is false.  You did imply it.  Anyone can say that with mathematical certainty.  And, just as certainly, I did not "admit to lying."  Nice try, Ralfie-boy.

Edited February 20, 2019 by Moronium

[sluggo]

everyone know that. 

What I'm saying is that you are making a fatal mistake to TRY to use a distance in the vertical axis, it the horizontal axis is already a distance axis.

 

With both axies being distance axies,  you no longer have a GRAPH, you don't have any vectors that represent velocity.

 

What you do have now is just a ordinary 2D map of Cartesian coordinates.

 

It is a MAP, showing locations ONLY, its can't show speed vectors,  any lines would represent ROADS traveled on. 

 

any school child KNOWS that!

 

Your ideas are therefore WRONG. 

Please admit that fact, and lets move on to something more interesting that has SOME chance of being real.

You can graph anything in 2 or 3 dimensions (variables). 

If c is the standard speed with a value of 1, then ct defaults to t. 

Light yr, light sec, etc, are distances true, but also equivalent times. 

The standard light speed of 1, eliminates the using the converion factor of 3(10)⁸. 

The graph (Minkowski diagram) becomes a history of positions or speed profile for an object.

It is NOT a 2D map, a common mistake leading to the metaphorical 'moving in time' interpretation.

Edited February 19, 2019 by sluggo

[sluggo]

marcospolo 56;

IF you realize that the axis labeled "ct" is NOT a distance axis, but a time axis, then why did they label it as ct?

 

 

 

[Just knowing algebra, you would see that Minkowski transformed t to ict in order to make a generalized form consisting of 4 coordinates instead of, 3 spatial and 1 temporal. That's what  mathematicians like to do,generalize.] 

[ralfcis]

Thanks to my argument with Moronium yesterday I woke up this morning realizing much of what I said is wrong. This doesn't mean Moronium will agree with what I'll be saying now. Maybe he will, we'll see.

 

1. Despite what Greene says, there is no such thing as an uninvolved 3rd party perspective that is outside and disagrees with the relative velocity between two participants. That wrong idea does not mean if you turn on a light bulb on your head and the light goes at c east and at c west that you  interpret the light is separating at 2c from your perspective and at 1 c from either light edge's perspective of the other edge. This is wrong, I'll explain why.

 

2. My STD showing the equivalence of the Minkowski and Loedel depictions of relative velocity at .6c is wrong. The vertical Earth frame  in the Loedel can't stay vertical in the Minkowski; it must shift into a .33c slanted line. This means the Cartesian coordinates do not represent the Earth frame but some background absolute frame that allows the depiction of relative velocity. 

 

3. As a result of the huge mistakes made in 1 and 2, my answer of the earth seeing the relative velocity between A and B as 1.6c is wrong. The answer is .9756c. Earth is not an uninvolved 3rd party.

 

4. My Hafele-Keating interpretation is also wrong. Two planes flying side by side will have no time dilation between them but orbiting in opposite directions will have. In order to accommodate this, the earth clock will have to be depicted as having a half speed relative velocity between that of the two planes. 

 

5. My example of flicking a laser beam from earth across the surface of the moon does not mean the light dot will exceed c either on the moon's surface or from earth's perspective.

 

This will take a lot of explanation in the next few posts.

Edited February 20, 2019 by ralfcis

[ralfcis]

Skip this.

 

I'm just lining up the videos from Greene where he talks about uninvolved 3rd party perspectives giving results that exceed c.

 

http://www.worldscienceu.com/courses/6/elements/CkPHej

 

It appears your relative velocity to light is not limited by c but your relative velocity to another person is.

 

I can't find the video where he gives a specific example of you seeing light separate in opposite directions and you can state light separates at 2c but it can't do that as soon as you bring in another person to offer his perspective on what's happening. I'm getting confused.

 

 

Here's a video of a lot of contradictory facts about MM experiment and accelerating frames. He seems to imply you can just measure the speed of light from a beam in progress. You need to know when and where the light started and compare that to the the time the beam reaches you.

 

http://www.worldscienceu.com/courses/6/elements/XV7lkE

Edited December 19, 2019 by ralfcis

[ralfcis]

I just wanted to avoid the motion of the earth spinning relative to the planes flying to be eliminated from the calculations. If the earth clock is fixed at the north pole, the plane clocks don't need to consider their relative velocity to the earth as they would if the earth clock was on the equator and the planes were doing an equatorial orbit in opposite directions.

[OceanBreeze]

It may help you to remember that velocity is a vector; it has both magnitude and direction, while speed is a scaler; it has only magnitude.

 

Two ships leaving earth in opposite directions at 0.8c are both velocities and vector quantities.

 

To get the relative Velocity between them the ship occupants must use Einstein’s velocity addition formula:

 

[math]V=\frac { 0.8c\quad +\quad 0.8c }{ 1\quad +\quad \frac { (0.8c\quad x\quad 0.8c) }{ { c }^{ 2 } }  } \quad =\quad \frac { 1.6c }{ 1.64 } =\quad 0.9756c[/math]

 

This result is also a velocity and a vector and it cannot exceed c in special relativity.

 

To get the simple closing (or opening) Speed between them, as seen from the Earth observer, he can just add their magnitudes to arrive at 1.6c

 

This does not violate SR because SR places no limit on closing speeds. Notice this is not a vector quantity as you cannot assign one specific direction to a closing speed. From the Earth observer’s frame, the ships are moving away in opposite directions, he cannot assign one direction to the closing speed, so it is not a vector.

 

If the Earth observer wants to know the relative velocity between the ships, he uses Einstein’s velocity addition formula same as the ship occupants do.

 

Another example of a closing speed is the speed at which the intersection point of the two blades of a scissors moves. In theory, this point can move faster than light speed if the scissors are big enough and close fast enough. Again, there is no violation of SR or of c because nothing physical is moving, only the point of intersection is moving.

 

Same again for the laser pointer going across the moon. This is an example of phase velocity which can exceed c.

[Moronium]

To get the relative Velocity between them the ship occupants must use Einstein’s velocity addition formula:

 

What do the guys going 0.9756c  relative to each other calculate the speed between the earth and the other guy to be, Popeye?  That's the main question here.

 

And what do they each calculate their own speed relative to the earth to be?

Edited February 20, 2019 by Moronium

[Moronium]

You didn't answer the question, Polly.

[ralfcis]

Ok Popeye, this is good info.  So a 3rd party observer can observe a speed greater than c but he can't observe a relative velocity greater than c. Speed is a magnitude and relative velocity has a direction but the time dilation caused by relative velocity is only dependent on its magnitude.  i need to get unconfused.

 

And the moon thing. I thought I was wrong because the light sprays out of the laser pointer at c and what I see as an instantaneous dot move across the moon surface is really a delayed dot because it still takes time for the light spray to start at one side of the moon and then get to the other. Hence the dot is not really moving greater than c from any perspective. Yes? I don't know anymore.

[Moronium]

But when it's all in one dimension (a straight line), velocity is speed, right?  Although velocity may technically be a vector, it's basically a scalar in those circumstances.  That's different than a guy travelling in a circle.

 

Relative to a given point you can say a guy is going north at 100 mph but nothing changes if you leave out the word "north."  You could substitute east, south, or west, and it would still be the same, i.e, 100 mph relative to that given point.

 

If you remove the earth from that example, what direction(s) could you even assign to A and B?

Edited February 20, 2019 by Moronium

[Moronium]

The answer is approximately c of the vacuum which is on average 2.99 hundred million meters per second

 

 

Wrong answer, sorry.

[OceanBreeze]

Ok Popeye, this is good info.  So a 3rd party observer can observe a speed greater than c but he can't observe a relative velocity greater than c. Speed is a magnitude and relative velocity has a direction but the time dilation caused by relative velocity is only dependent on its magnitude.  i need to get unconfused.

 

.

 

Exactly! You got it.

 

 

And the moon thing. I thought I was wrong because the light sprays out of the laser pointer at c and what I see as an instantaneous dot move across the moon surface is really a delayed dot because it still takes time for the light spray to start at one side of the moon and then get to the other. Hence the dot is not really moving greater than c from any perspective. Yes? I don't know anymore

 

 

There is a delay in the light beam getting from the Earth to the moon, sure and that will be apparent when you first turn the laser on and when you first start to move it but it won’t slow down the motion of the beam as it scans across the surface. The moon fills about one degree of arc in the sky, so you only need to move the laser through one degree of arc to scan the whole surface. You can do that in one second.

 

So, in one second, the beam moves across the diameter of the moon, 3.5E6 meters so a little faster than c. But that is only a phase velocity so it isn’t a violation of c as the absolute speed limit in the universe because of that delay you mentioned. No information is being sent to any part of the moon faster than c.

 

This happens inside waveguides all the time. The radio wave does not travel straight down the guide, but bounces off the sides. As the wavefront heads toward one side at c, it also drags along the side of the guide and the both the wavefront and the edge dragging on the side get to the same point at the same time. Since the edge dragging on the side travels a longer distance, it is moving faster than c. But no information is getting to the point faster than the wavefront, so no violation.

[OceanBreeze]

But when it's all in one dimension (a straight line), velocity is speed, right?  Although velocity may technically be a vector, it's basically a scalar in those circumstances.  That's different than a guy travelling in a circle.

 

Relative to a given point you can say a guy is going north at 100 mph but nothing changes if you leave out the word "north."  You could substitute east, south, or west, and it would still be the same, i.e, 100 mph relative to that given point.

 

If both a direction and a magnitude are given, it is a vector and a velocity.

 

If only the magnitude is known and not the direction, it is a speed.

[OceanBreeze]

What do the guys going 0.9756c  relative to each other calculate the speed between the earth and the other guy to be, Popeye?  That's the main question here.

 

And what do they each calculate their own speed relative to the earth to be?

 

 

That's in my answer.

 

They each have Velocities with respect to the Earth of 0.8c in opposite directions.

 

Their relative Velocity to each other is 0.9756c

 

The only thing that is a speed is the closing speed (it is called closing speed even though they are moving away from each other, Google closing speed) as seen by the Earth observer and that is 1.6c

[Moronium]

That's in my answer.

 

  I don't see it.  Are you sure you understand the question?  Well, two questions, actually.

Edited February 20, 2019 by Moronium

[OceanBreeze]

  I don't see it.  Are you sure you understand the question?  Well, two questions, actually.

 

You maybe don't understand the answer.