Relativity And Simple Algebra

[Moronium]

Maybe, let me restate the questions...

 

[OceanBreeze]

Even if you're going .‾9 c an object moving at c next to you will still be moving at c

 

There won't be any object going at c, 

 

But you are right if you are talking about a photon.

[Moronium]

We have 3 objects.  A, E, and B.  I take you to be saying that A "sees" himself going .975 c relative to B.  I got that much.  But now the questions are:

 

1. What does A "see" the speed between himself and E to be?

 

2,  What does A calculate the speed between E and B to be?

 

Did you already answer those two questions?  If so, I missed it.

Edited February 20, 2019 by Moronium

[OceanBreeze]

We have 3 objects.  A, E, and B.  I take you to be saying that A "sees" himself going .975 c relative to B.  I got that much.  But now the questions are:

 

1. What does A "see" the speed between himself and E to be?

 

2,  What does A calculate the speed be E and B to be?

 

 

1. What does A "see" the speed between himself and E to be?  A has a VELOCITY of 0.8c with respect to E

 

2,  What does A calculate the speed be E and B to be? A calculates that B has a VELOCITY of 0.8 c with respect to E

 

E sees a closing speed between A and B of 1.6 c

 

E calculates the relative velocity between A and B of 0.975c

[OceanBreeze]

We have 3 objects.  A, E, and B.  I take you to be saying that A "sees" himself going .975 c relative to B.  I got that much.  But now the questions are:

 

1. What does A "see" the speed between himself and E to be?

 

2,  What does A calculate the speed between E and B to be?

 

Did you already answer those two questions?  If so, I missed it.

 

Yes, you missed it.

[OceanBreeze]

You know what I meant

 

Yes, but it helps to be precise.

[Moronium]

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.

 

 

I see that in you answer you capitalize VELOCITY for emphasis.  But I'm not getting the significance of the distinction between velocity an speed here.

 

How can he see .8 and .8 add up to.975?   I mean, apart from the simple answer that it's because the formula says so?

Edited February 20, 2019 by Moronium

[OceanBreeze]

You saw Post # 100? That is Einstein's velocity addition formula.

 

You are asking me to explain this formula?

 

I can do that but not now. It will take some time and it will involve a fair bit of math.

 

Do you really want to go there?

[OceanBreeze]

Precision, by very definition, is not possible. Precision is always off by the decimal place that you had to round to find an infinite amount of digits into your equation.

 I meant language precision. You said "object" but you meant "photon" that is not being precise is it?

[Moronium]

You saw Post # 100? That is Einstein's velocity addition formula.

 

You are asking me to explain this formula?

 

I can do that but not now. It will take some time and it will involve a fair bit of math.

 

Do you really want to go there?

 

No, that's not my question, at all.  I just asked you if you had an answer to the question, without regard to that.  It's just a formula, after all.  I'm interested in real life speeds, not formulas for calculations used by subjective observers.

Edited February 20, 2019 by Moronium

[OceanBreeze]

No, that's not my question, at all.  I just asked you if you had an answer to the question, without regard to that.  It's just a formula, after all.  I'm interest in real life speeds, not formulasfor calculations used by subjective observers.

 

Then I have no idea what you are asking.

 

We are not discussing "real life" speeds that are encountered every day!

 

We are talking about relativistic velocities and they can only be properly added by using Einstein"s velocity addition formula which has been verified by such things as  particle accelerators and the study of muons and other cosmic phenomena.

 

You are asking me to answer your question without regard to that formula? That would result in an incorrect answer.

Anyway, that's all the time I have today.

[Moronium]

E calculates the relative velocity between A and B of 0.975c

 

 

What does A see the relative velocity (speed) between himself and B to be then?  You're telling how the earth calculates it, but how does A calculate it?

 

I take it that you're saying that A sees himself travelling at 1.6c relative to B, and vice versa, and that's OK because that's a "closing speed,"  even though they are separating, not actually closing. It's just that the earth doesn't see it that way.

 

If so, let me put the question this way.

 

1.  Using a "radar gun" (doppler effect) does E measure the speed of A relative to itself to be .8c?  If so, would that be a "real" speed?

 

2.  Using a "radar gun" does E measure the speed of b relative to itself to be .8c?  If so, would that be a "real" speed?

 

3.  If so, then why does he add those together and somehow get a sum of .975c?

 

I mean other than by saying the speeds he is measuring can't be right, and his radar gun has to be mistaken, BECAUSE he (mistakenly or not) assumes that the speed between them can't exceed c?

 

Without that presumption (and that's all it is) what do you think he would "add" them up to be?  1.6c, right?

 

I have a feeling you'll say you can't possibly understand my question, but who knows?

Edited February 20, 2019 by Moronium

[OceanBreeze]

Read Post #100 FFS!

[Moronium]

We are talking about relativistic velocities and they can only be properly added by using Einstein"s velocity addition formula which has been verified by such things as  particle accelerators and the study of muons and other cosmic phenomena.

 

 

How does our lab assessment of the speed of a particle or a muon tell us ANYTHING about how the muon sees things? All my questions relate to 3 different perspectives, not just one (the earth's).

[ralfcis]

I'm googling closing speed and it's just not entering my brain in relation to relativity. I need to read up on this more. The problem I'm having is looking at Greene's videos. He's not precise with terms and I don't know when he means relative velocity and when he means closing speed. This is the example I'm having trouble with. Whether A or B are moving towards or away from each other, they will measure c as the same constant. But if A is moving toward the beam of light B sends her, I assume her closing speed to the light is greater than c but her relative velocity to the light coming toward her is c? Am I getting close to understanding this concept? Is closing speed used in relativity?

[Moronium]

Read Post #100 FFS!

 

 

In other words, consult the formula.

 

Do you have other answer to my post, 136, Popeye?

[ralfcis]

Ok so every velocity on earth is relative to earth. So a jet goes 750 mph relative to earth but if he's closing in on a jet going 740 mph, his closing speed is 10 mph. Relativity would call that relative velocity between the two planes but due to the relativistic velocity combo formula, that relative velocity would be slightly less than 10 mph. At high speed, relative velocity becomes much less than closing velocity which remains Newton's definition of relative velocity. Is that correct now?

 

PS. So if this is correct then if you send light signals between the two participants, those light signals have both a closing speed which is not c and a relative velocity to everything as c. So light signals sent between two .33c participants will have different closing speeds from a depiction of the relative velocity as .6c between the two participants. Light can travel at any closing speed it wants. I can use this in my investigation of using light signals to establish the true age of the participants.

Edited February 20, 2019 by ralfcis