The Underlying Problem With Some Science Is Interpretation.

[OceanBreeze]

:) Well I can see someone hates to be proven wrong. Watch out, flying dummy alert!

 

TSTOR is a specific paper that describes some of the effects of relative motion. SR is the effects of relative motion. TSTOR is one specific piece of work relating to how nature works. SR is how nature works. What you're saying is equivalent to trying to refute the great mass extinctions of life on the basis that they don;t fall withing the framework of evolution. It makes no sense!

 

 

 

Oh yeah, I was wrong. In fact, I was very wrong, and I admit it.

 

You see, I thought this was a Science Forum, not some place for Idiots to make up their very own pseudo-voodoo-Xience

 

A place where Einstein's special theory of relativity is relegated to the waste bin in favor of some Idiot's special relativity of nature!

 

A place where the laws of conservation of momentum and energy still hold, not where some Idiot can deny those laws and continue to post his crap.

 

Yessir, I was totally wrong.

 

Now, can a moderator please delete my fugging user account. Thanks in advance.

[A-wal]

Read carefully and try to understand.

 

TSTOR only deals with motion relative to an observer.

 

What I'm talking about is the relative velocity between two objects from the frame of reference of a third object, the observer.

 

This is outside the framework of what TSTOR describes (at least I'm fairly sure it doesn't touch on this).

 

The error you keep making is to apply the velocity addition formula from TSTOR in a situation where it doesn't apply.

 

When two objects are in motion relative to an observer you don't apply time dilation and length contraction (the velocity addition formula) to their velocity relative to each other from the frame of reference of that observer.

 

Whenever you apply that formula you are changing the frame of reference by applying time dilation and length contraction.

 

In this case the frame of reference changes to that of one of the objects that are in motion relative to the initial observer. You are in effect, switching to a different observer.

 

You can never apply time dilation and length contraction (the velocity addition formula) without changing the frame of reference.

 

Objects that are moving away from each at 0.8c in their own reference frames are moving away each other at 1.2c in the reference frame of an observer that's positioned between them so that they're moving away from that observer at an equal velocity (0.6c in this case).

 

This is all perfectly in accordance with TSTOR, a description which only includes the velocity of objects relative to an observer, not relative to each from the perspective of an observer.

 

Get over it and stop being such a whiny baby!

Edited December 29, 2016 by A-wal

[CraigD]

An object is moving away from the observer at 0.6c and a second object is moving away from the observer at 0.6c in the opposite direction. They are moving away from each other at 1.2c in this frame. Now if we apply the velocity addition formula to get 0.8c

Your arithmetic is wrong here. [math]\frac{0.6+0.6}{1+0.6 \cdot 0.6} = \frac{15}{17} \dot= \, 0.882353[/math], not 0.8.

 

You could work out the masses and collision velocity of 0.8c of the particles in their own frames and say 'look, the velocity addition formula does apply' but you can also simply use masses and collision velocity of 1.2c of the particles in the lab's frame with applying the velocity addition formula.

You must use the true speed of the particles, for example 0.6 c and 0.6c, so assuming the 2 particles have the same mass, m, the energy would be [math]E = \frac{2 m c^2 }{\sqrt{1-0.6^2}} = \, 2.5 m c^2[/math] (that’s a wimpy accelerator!).

 

If you use a speed greater than c, you get a weird result with a [math]i=\sqrt{-1}[/math] term in it, like, for a single particle at 1.2 c, [math]E = \frac{m c^2 i 5}{\sqrt{11}} \dot= \, 1.5176 i m c^2[/math]. To have such a result make sense, [math]m[/math] has to have an [math]i[/math] term. Though on the scientific fringe, some physicist, like Robert Ehrlich in this paper, have suggested there might be particles with such masses, such as the neutrino. Though I pretty sure for many reasons he’s wrong, Ehrlich’s made predictions that can be tested with data from the KATRIN beta decay spectrometer, which is expected to begin producing non-test data in 2017, so we won’t have to wait long to know.

 

Okay I'll make this perfectly clear because their seems to be some confusion:

SR = Special relativity, as in the effects of relative motion in nature.

TSTOR = The Special Theory Of Relativity, a specific scientific paper that deals with the same subject.

I’ve never seen a widely accepted text or respected scientist describe Special Relativity this way. Every one of them understands is to be a scientific theory describing the relationship of time and space such that a postulate not present the accepted theory that it superseded, Galilean relativity, is included. That postulate is that the speed of light is the same for all observers, regardless of the motion of the light source.

 

A scientific theory is not the same thing as the aspect of the physical world is seeks to explain. Semanticists often describe this non-equivalence with the phrase “the map is not the territory”

 

A scientific theory is nor the same thing as the papers and other artifact used to communicate the theory, any more than a book with a title “Aircraft or WWII” are the aircraft it describes. I can’t recall seeing anyone, other than you, in this thread, suggest that a theory is equivalent to a paper about the theory, but if I had to describe this false equivalence in the same vein as above, I’d say “the title of the map is not the map”.

 

There's no need to back up my claims because everything I've said is in accordance with standard theory. It's a very silly rule anyway

Yes, when posting at this site, you do need to follow the site rules, and the site rule requiring us to back up our claims with links or references is not silly. When it’s not followed, what’s happening in this thread happens: people not enjoying the discussion of science. :(

 

If what you’re saying was “in accordance with standard theory”, you would find it trivial to show this with links and references to standard sources. Just saying this isn’t adequate – you need to show it. I’m nearly certain you can’t.

 

No opinions my be expressed on this forum unless you can show that those opinions have been previously expressed by others before you and accepted by the scientific community.

For centuries, academics scientific and otherwise have had no difficulty expressing original ideas while making them understandable with references to previously expressed ideas. References make original ideas understandable, and serve to show that they are original. I’ve never seen a credible person claim that richly connecting an idea to other ideas worsens it.

 

The tools provided by this website make it easy to create links. Use them. The “hypo” in hypography stands for “hyperlink”, not “under, lower, less than”.

[A-wal]

Right I quit! Please delete my account. Waaaaaaa! :)

 

Your arithmetic is wrong here. [math]\frac{0.6+0.6}{1+0.6 \cdot 0.6} = \frac{15}{17} \dot= \, 0.882353[/math], not 0.8.

Hmm. I was going by memory. I know there's one that works out perfectly, maybe 0.7 + 0.7 = 0.9? I'll make sure I get that right before I use it as an example again.

 

If you use a speed greater than c, you get a weird result with a [math]i=\sqrt{-1}[/math] term in it, like, for a single particle at 1.2 c, [math]E = \frac{m c^2 i 5}{\sqrt{11}} \dot= \, 1.5176 i m c^2[/math]. To have such a result make sense, [math]m[/math] has to have an [math]i[/math] term. Though on the scientific fringe, some physicist, like Robert Ehrlich in this paper, have suggested there might be particles with such masses, such as the neutrino. Though I pretty sure for many reasons he’s wrong, Ehrlich’s made predictions that can be tested with data from the KATRIN beta decay spectrometer, which is expected to begin producing non-test data in 2017, so we won’t have to wait long to know.

Really? Okay so to get the right collision energy you have to use the velocity between the objects in their frame, not from the perspective of an external observer.

 

I’ve never seen a widely accepted text or respected scientist describe Special Relativity this way. Every one of them understands is to be a scientific theory describing the relationship of time and space such that a postulate not present the accepted theory that it superseded, Galilean relativity, is included. That postulate is that the speed of light is the same for all observers, regardless of the motion of the light source.

A scientific theory is not the same thing as the aspect of the physical world is seeks to explain. Semanticists often describe this non-equivalence with the phrase “the map is not the territory”

A scientific theory is nor the same thing as the papers and other artifact used to communicate the theory, any more than a book with a title “Aircraft or WWII” are the aircraft it describes. I can’t recall seeing anyone, other than you, in this thread, suggest that a theory is equivalent to a paper about the theory, but if I had to describe this false equivalence in the same vein as above, I’d say “the title of the map is not the map”.

That was exactly my point! That the special theory of relativity is merely a description of one aspect of nature, one that doesn't include the scenario of the relative velocity of objects from the perspective of a separate observer. Of course it's possible to use a model to describe a scenerio outside of the model's original context as OceanBreeze is trying to do but it doesn't work in this scenario.

 

Yes, when posting at this site, you do need to follow the site rules, and the site rule requiring us to back up our claims with links or references is not silly. When it’s not followed, what’s happening in this thread happens: people not enjoying the discussion of science. :(

 

If what you’re saying was “in accordance with standard theory”, you would find it trivial to show this with links and references to standard sources. Just saying this isn’t adequate – you need to show it. I’m nearly certain you can’t.

The only part of what I said that doesn't agree with standard theory (other than remembering 0.6+0.6=0.8 wrong) is the mass/energy involved in a collision at velocities in the frame of reference of an external observer.

 

How can I possibly provide a reference to the velocities of objects relative to each other from an observer's frame of reference when the special theory of relativity only describes the velocity of objects relative to the observer?

 

For centuries, academics scientific and otherwise have had no difficulty expressing original ideas while making them understandable with references to previously expressed ideas. References make original ideas understandable, and serve to show that they are original. I’ve never seen a credible person claim that richly connecting an idea to other ideas worsens it.

The tools provided by this website make it easy to create links. Use them. The “hypo” in hypography stands for “hyperlink”, not “under, lower, less than”.

I am! I'm using the established model and what I'm describing is hardly an original idea. It's simply that OceanBreeze misunderstands how, or rather when to apply the velocity addition formula. He's trying to use it in a scenario outside the framework of the model in a situation where it doesn't apply.

 

 

All of this is (apart from me thinking that you can use the collision velocity of objects in the frame of reference of an external observer to work out the mass/energy involved in the collision) is beside the point. I'll make this as clear as I can.

 

When objects are in motion relative to each other from the frame of reference of a separate observer you don't apply time dilation and length contraction (the velocity addition formula) as OceanBreeze has been doing because as soon as you do that you are getting the relative velocity of those objects in their own frames of reference. If two objects are moving away from the observer at 0.6c in opposite directions then their velocity relative to each other in the frame of reference of the observer is 1.2c. If you apply the velocity addition formula to get 0.882353c then you get the velocity of those two objects relative to each other in their own frames. You have now moved out of the frame of reference of the initial observer!

Edited December 30, 2016 by A-wal

[A-wal]

If you use a speed greater than c, you get a weird result with a [math]i=\sqrt{-1}[/math] term in it, like, for a single particle at 1.2 c, [math]E = \frac{m c^2 i 5}{\sqrt{11}} \dot= \, 1.5176 i m c^2[/math]. To have such a result make sense, [math]m[/math] has to have an [math]i[/math] term.

Are you sure this is right?

 

If you use their relative velocity in the lab frame I would have thought you'd get the same result as using their own frames, or any frame you like. Are you sure you're not applying a formula that's meant for the velocity of the collision in the frame of either particle? Because then you would get weird results at collision velocities greater than c.

 

Although the result should be infinite energy being released because the particles would have infinite mass, right?

[fahrquad]

It is painfully obvious that no amount of logic and reason are going to convince XYZ.  You guys don't need to waste your time responding.

[A-wal]

It is painfully obvious that no amount of logic and reason are going to convince XYZ.

Or OceanBreeze apparently.

[sluggo]

3) Where he goes wrong is in thinking that the third observer can measure the closing velocities of the two moving observers as greater than c. He can’t!

Closing velocities, which are added algebraically and are not use in relativity.

 

What about (c±v) Einstein used in the derivation of the coordinate transformations?

When docking at the space station, moving 1000's mph, the closing speed is critical at approx 1"/sec. It's important in real world applications, and does not violate any rule in SR. Like all the examples used, it's a changing spatial  relation, not moving mass.

 

 

 

The speed of light is the speed limit of the universe, so it follows that no observer will see any other observer approaching or receding at a speed greater than c. But what if observers A and B are both moving toward each other with speeds approaching c as seen by an external observer? How will A and B measure their relative speeds? This is an example of Einstein velocity addition.

 

This example does not require SR velocity addition. A and B are moving at speeds (a, b) measured by a third observer. The expression

 

ut=(b-a)/(1-ab)

 

applies but with one of the corresponding speeds as negative.

 

The SR velocity addition expression applies when the speeds of each object are measured from different frames.

Assume F0 the ref frame, F1, F2, F3 moving at .3, .6, .9c respectively relative to F0, in the x direction. Let each measure the speed of the frame in front of it, using the expression

ut=(vt-vm)/(1-vtvm)

 

with t the target frame and m the measuring frame. Notice ut>(vt-vm) for all frames except F0.

The total value of the measurements u3=.30+.37+.65=1.32.

F0 cannot rely on the measurements reported from the other frames since it results in faster than light speed for F3. To calculate u, the speed of F2 relative to F0,  based on v1, the speed of F1 as measured by F0, and v2, the speed of F2, as measured by F1, the expression

 

v2=(u-v1)/(1-uv1)

 

is solved for u giving

 

u=(v1+v2)/(1+v1v2),

 

the correct form for the ADDITION of velocities.

For the example, u=.67/1.11=.60

which is the speed F0 would measure directly for F2.

Also, when measuring speed, time dilation is irrelevant.

Speed =distance/time=time* speed/time. The gamma factor is in the numerator and the denominator and thus cancels out. 

Edited December 31, 2016 by sluggo

[OceanBreeze]

What about (c±v) Einstein used in the derivation of the coordinate transformations?

When docking at the space station, moving 1000's mph, the closing speed is critical at approx 1"/sec. It's important in real world applications, and does not violate any rule in SR. Like all the examples used, it's a changing spatial  relation, not moving mass.

 

 

 

 

 

A couple of things:

1. 17,000 mph is fast, but it is not a relativistic velocity
2. The ISS and the capsule are both travelling at nearly the same velocity during docking, so only relative (not relativistic) velocities matter, simple velocity addition and subtraction is all that is required.
3. Moving masses are most certainly involved and F=ma applies.

 

This example does not require SR velocity addition. A and B are moving at speeds (a, :cool: measured by a third observer. The expression

 

 

The example you are referring to is a direct quote:

 

"The speed of light is the speed limit of the universe, so it follows that no observer will see any other observer approaching or receding at a speed greater than c. But what if observers A and B are both moving toward each other with speeds approaching c as seen by an external observer? How will A and B measure their relative speeds? This is an example of Einstein velocity addition"

 

It is taken from here

 

 

If you are certain that SR velocity addition is not required for this example, I suggest you contact the HyperPhysics website and tell them they have it all wrong.

 

 

 

[A-wal]

If you are certain that SR velocity addition is not required for this example, I suggest you contact the HyperPhysics website and tell them they have it all wrong.

And you still don't get it. You're no better than xyz. You're using rules from a model that you keep referencing but have no understanding of and trying to apply those rules to situations that they can't be applied to. Listen carefully and try to understand.

 

The velocity addition formula is how to apply time dilation and length contraction to velocities of objects relative to the observer, not the velocities of other objects relative to each other in the frame of an observer.

 

When two objects are moving away from the observer in opposite directions at 0.6c their velocity relative to each other In the observer's reference frame is 1.2c.

 

Their velocity relative to each other in their own frames is different (0.882353c) because of the velocity addition formula that applies to the velocity of an object relative to an observer (in object A's frame object B is moving away from stationary object A at 0.882353c and in object B's frame object A is moving away from stationary object B at 0.882353c).

 

If both objects were to accelerate by the same amount again (assuming they began in the same frame of reference of the observer) then they would both be moving away from the observer at 0.882353c because the velocity addition formula does apply to the velocity of objects relative to the observer but they'd be moving away from each other at 1.764706c (double their velocity relative to the observer) because the velocity addition formula doesn't apply to the velocity of other objects relative to each other in an observer's frame of reference.

[sluggo]

OceanBreeze#179

Moving masses are most certainly involved and F=ma applies.

-------------

The subject is NOT the moving masses, but the decreasing distance (which has no mass) between them. It changes at approx. 1" per second.

 

from the 1905 paper A. Einstein, part 1, par5 The Composition of Velocities

V = (v+w)/(1+vw/cc)

This is the expression shown for observer A at the hyperphysics site, the one you didn’t copy!

 

The need for this composition results from the definition in par 1 that the transit times for light outbound and inbound be equal for a round trip, and maintain a constant c. His reasoning is acceptable since there is no way to determine precisely your speed relative to light and when the reflection event occurs. A later, more emphatic quote:

"That light requires the same time to traverse the same path A to M as for the path B to M is in reality neither a supposition nor a hypothesis about the physical nature of light, but a stipulation which I can make of my own freewill in order to arrive at a definition of simultaneity."[1]

Relativity The Special and the General Theory

Albert Einstein 1961 Crown Publishers Inc. pg 23

 

Using the form that develops in the process of measuring the speed of a moving object,

 

V = (v-w)/(1-vw/cc)

 

results in excessive speed when governed by the simultaneity convention.

[OceanBreeze]

 

OceanBreeze#179

Moving masses are most certainly involved and F=ma applies.

-------------

The subject is NOT the moving masses, but the decreasing distance (which has no mass) between them. It changes at approx. 1" per second.

 

 

 

Oh really? Is that what the 'subject" is?

 

I suggest you should try using Google sometimes Before you post something…..it might save you some embarrassment. You think the distance between the capsule (which has mass) and the ISS (which has more mass) just closes, without any force being involved, because the space between them has no mass? You think Newton’s Laws of Motion, and Force is not required?

That is comedy gold.

Here, read this (hopefully it is not too high level for you)

 

"In order for the components, crews, and supplies to be delivered to the International Space Station, a system needs to be in place that allows the Space Shuttle to dock, or attach, to the structure. One procedure practiced on Mir includes the docking techniques. After the Space Shuttle is launched and once inserted into an initial orbit, the Commander uses the Orbital Maneuvering System to thrust the Space Shuttle from one orbit to another. Using the Orbital Maneuvering System and Reaction Control System, the Space Shuttle is positioned approximately 110 meters below Mir. The Reaction Control System is used to complete the approach of the Space Shuttle toward Mir. The Reaction Control System is used to change speed, orbit, and attitude (pitch, roll, and yaw.) The pitch is an angular rotation about an axis parallel to the widthwise axis of a vehicle. The roll is the angular rotation movement about the lengthwise axis of the vehicle. The yaw is the angular rotation movement about the heightwise axis of the vehicle. The Reaction Control Systems are located in the nose and tail sections of the Space Shuttle. When the systems are activated, they are fired in a direction opposite to that which the Commander wishes to move. If the Commander wants to move to the left, he or she fires the Reaction Control System on the right, and if the desired movement is to the right, the system is fired on the left. The Space Shuttle travels toward Mir with a force that is equal and opposite to the Reaction Control System firings (Newton’s Third Law)."

 

 

 

 

 

from the 1905 paper A. Einstein, part 1, par5 The Composition of Velocities

V = (v+w)/(1+vw/cc)

This is the expression shown for observer A at the hyperphysics site, the one you didn’t copy!

 

The need for this composition results from the definition in par 1 that the transit times for light outbound and inbound be equal for a round trip, and maintain a constant c. His reasoning is acceptable since there is no way to determine precisely your speed relative to light and when the reflection event occurs. A later, more emphatic quote:

"That light requires the same time to traverse the same path A to M as for the path B to M is in reality neither a supposition nor a hypothesis about the physical nature of light, but a stipulation which I can make of my own freewill in order to arrive at a definition of simultaneity."[1]

 

Relativity The Special and the General Theory

Albert Einstein 1961 Crown Publishers Inc. pg 23

 

Using the form that develops in the process of measuring the speed of a moving object,

 

V = (v-w)/(1-vw/cc)

 

results in excessive speed when governed by the simultaneity convention.

 

 

Too bad you don't understand your own references. Everything I have said is supported by Einstein's SR and nothing you have said is.

 

In SR, there is never a velocity greater than c, period.

 

When you write "It results in “excessive speed”, What does that even mean? Do you mean a speed greater than c?

If that is what you mean, you do not understand SR.

 

Use the equation you posted and do the math. Or maybe I need to do it for you?

V = (v+w)/(1+vw/cc)

If v = w = c what do you get for V?

Hint: I get 2c/2 = ?

 

Everything I have posted in this thread, I have provided the reference links to support, and the mathematics, which you do not understand. If you want to learn something, stop making unsupported assertions and READ.

 

 

[A-wal]

In SR, there is never a velocity greater than c, period.

Technically true if you mean SR as in the specific paper called the special theory of relativity but not true in general.

 

Listen xyz2.0, all this childishness and dummy throwing you keep doing is nothing but embarrassment that you've been shown up for what you are. I have no idea why you've been allowed to get away with so much.

 

This is very simple and I'm I'm going to explain it one more time for you. The rule that objects can only travel at under the speed of light is a rule that only applies to the velocity of objects relative to the observer. It does NOT apply to the relative velocity of other objects from the perspective of that observer, the speed limit for that is anything under 2c because each one can travel at under 1c relative to the observer. The more general rule that applies to all situation (including angular velocity is this:

 

The distance between any observer and any other object can't change at or faster than the speed of light in the inertial frame of reference of the observer and therefore the distance between any two objects can't change at or faster than twice the speed of light in any inertial frame of reference.

 

This is what happens when you google information and just parrot it make with no understanding of what you're saying, you make dumb mistakes. Please provide a reference for your ridiculous claim that you ever apply the velocity addition formula from tSToR without changing reference frames!

[OceanBreeze]

Technically true if you mean SR as in the specific paper called the special theory of relativity but not true in general.

 

Listen xyz2.0, all this childishness and dummy throwing you keep doing is nothing but embarrassment that you've been shown up for what you are. I have no idea why you've been allowed to get away with so much.

 

This is very simple and I'm I'm going to explain it one more time for you. The rule that objects can only travel at under the speed of light is a rule that only applies to the velocity of objects relative to the observer. It does NOT apply to the relative velocity of other objects from the perspective of that observer, the speed limit for that is anything under 2c because each one can travel at under 1c relative to the observer. The more general rule that applies to all situation (including angular velocity is this:

 

The distance between any observer and any other object can't change at or faster than the speed of light in the inertial frame of reference of the observer and therefore the distance between any two objects can't change at or faster than twice the speed of light in any inertial frame of reference.

 

This is what happens when you google information and just parrot it make with no understanding of what you're saying, you make dumb mistakes. Please provide a reference for your ridiculous claim that you ever apply the velocity addition formula from tSToR without changing reference frames!

 

 

You listen, you arrogant punk,  any discussion about Special Theory of Relativity (SR) must be assumed to be about Einstein’s SR, as that is the only SR that is recognized. Endless arguments and much chaos will ensue if everyone is thinking of their own theory of SR. You can't make up your own crap "theories"  in science!

 

Intuitive notions about relative velocities just have to be discarded no matter how much sense they make to you, when you are talking about SR, and you just have to apply velocity addition as it is delineated by Einstein.

 

Intuitively, you will get velocities such as 1.5c and 0.5c, as you did in this thread, and that just does not hold up in SR.

 

Face the fact that you are wrong or you will never learn anything and go through life ignorant and arrogant.

 

Here is another way to say it, from someone who claims to have a Phd in Physics (although the use of language makes me a bit skeptical)

 

"Because the speed of light must be constant. Well, that's a simple sentence but has lot of implications.

 

Imagine you're moving on a spaceship at 99.9% the speed of light pursuing another spaceship moving at 99.9999% the speed of light. You must destroy the ship then you launch a laser beam to it. Well, the speed of light is constant for both.

 

That's mean you'll see the laser beam moving away at the speed of light (even you're at 99.9% of that speed), the people on the another spaceship will see the laser beam reach them at the speed of light (even there're moving at 99.9999% of that speed). And if there's another observer will measure the laser bean moving from your spaceship to the another one at the speed of light (even if is quiet o moving at any velocity on any direction).

 

Then what's different for the 3 observers? Time. When you has a velocity, time is different because you must still measure the same speed of light."

 

Do you understand that? There is never any velocity greater than c, for any observer in any inertial frame of reference.

 

You are flat out wrong. Get over it.

 

I do like the “Nobody knows” honesty in that reply, because really, nobody, including Einstein, has ever figured out what TIME really is. We can measure it and work with it in countless equations and even say it slows down, but we don’t know what it is.

 

That’s why I have some empathy for xyz and his threads; he at least is talking about something we really do not understand, and there are some very intelligent physicists who are of the opinion that Time does not even exist! XYZ is a better poster than you will ever be, in my opinion.

 

On the other hand, I have no empathy for someone who denies the well-established laws of the conservation of energy and angular momentum. You are responsible for bringing THAT troll back into this forum, even though you had no participation in that thread at all. That is probably because you also do not understand such basics as COE and COM.

 

 

[A-wal]

You listen, you arrogant punk,  any discussion about Special Theory of Relativity (SR) must be assumed to be about Einstein’s SR, as that is the only SR that is recognized. Endless arguments and much chaos will ensue if everyone is thinking of their own theory of SR. You can't make up your own crap "theories"  in science!

It's very simple. The Special Theory Of Relativity only describes the velocity of objects relative to an observer. Two objects can of course move at anything under 2c relative to each other from the perspective of that observer. How many times are you going to have to be told this before it sinks in?

 

Intuitive notions about relative velocities just have to be discarded no matter how much sense they make to you, when you are talking about SR, and you just have to apply velocity addition as it is delineated by Einstein.

No you never apply the velocity addition formula to object that are in motion relative to each other from the perspective of a third observer. That would make no sense what so ever. It would mean that if an object were moving away from you at say 0.6 and another object anywhere in the universe were moving away from you in the opposite direction then the first object would be slowed down so that the two couldn't be moving at over 1c relative to each other. That's incredible stupid and certainly not from anything described in the special theory of relativity.

 

Face the fact that you are wrong or you will never learn anything and go through life ignorant and arrogant.

Yea I'm the one who's wrong about this, good one. :)

 

Do you understand that? There is never any velocity greater than c, for any observer in any inertial frame of reference.

There is never a velocity greater than c of an object relative to the observer! It doesn't apply to the velocity of other objects relative to each other. This is painfully obvious and the fact that you can't see it shows that you really have no business attempting to argue about a model that you clearly have no real understanding of.

 

You are flat out wrong. Get over it.

Yea keep saying it, that will make it true.

 

That’s why I have some empathy for xyz and his threads;

I'm not surprised, you have an awful lot in common. Both trying to argue from ignorance with no actual understanding of the subject. At least xyz is trying to think for himself.

 

XYZ is a better poster than you will ever be, in my opinion.

You really are the most childish poster on this forum by a very big margin!

 

On the other hand, I have no empathy for someone who denies the well-established laws of the conservation of energy and angular momentum. You are responsible for bringing THAT troll back into this forum, even though you had no participation in that thread at all. That is probably because you also do not understand such basics as COE and COM.

You think because I pointed out that he didn't deserve a ban that means I don't understand the conservation of energy and momentum? With logic like that it's no wonder you're having so much trouble understanding when to apply the velocity addition formula.

Edited January 11, 2017 by A-wal

[OceanBreeze]

It's very simple. The Special Theory Of Relativity only describes the velocity of objects relative to an observer. Two objects can of course move at anything under 2c relative to each other from the perspective of that observer. How many times are you going to have to be told this before it sinks in?

 

 

That turd floats! It will never sink in.

 

 

No you never apply the velocity addition formula to object that are in motion relative to each other from the perspective of a third observer. That would make no sense what so ever. It would mean that if an object were moving away from you at say 0.6 and another object anywhere in the universe were moving away from you in the opposite direction then the first object would be slowed down so that the two couldn't be moving at over 1c relative to each other. That's incredible stupid and certainly not from anything described in the special theory of relativity.

 

 

 

Is that so? This is from Boston University. Scroll down to the paragraph on Relative Velocities.

 

Quoting from that source with a nice picture (just for you)

 

 

Let's say you now stand on an intergalactic freeway. You see a truck heading in one direction at 0.6c, and a car heading in the opposite direction at 0.7c. What is the velocity of the truck relative to the car? It is not 1.3c, because nothing can travel faster than c. The relative velocity can be found using this equation:

 

 

In this case, u is the velocity of the car relative to you, v is the velocity of the truck relative to you, and u' is the velocity of the car relative to the truck. Taking the direction the car is traveling to be the positive direction:

 

 

So, now everyone involved agrees on this:

• the truck is traveling at 0.6c relative to you, and 0.915c relative to the car.

• the car is traveling at 0.7c relative to you, and 0.915c relative to the truck.

• you are traveling at 0.6c relative to the truck, and 0.7c relative to the car.

 

(Those are the only velocities that pertain to this situation in Special Relativity. As I said earlier, and I think Craig said the same thing, if you add them together in this way, u' = u + v, you no longer are talking about velocities, but speeds. A velocity has both magnitude and direction. A closing speed has only magnitude, if you assign a direction to it, it is a velocity and cannot be greater than c. How can the third observer (your stickman) assign a direction to the closing speed?)

 

Continuing the quote:

 

The relativistic equation for velocity addition shown above can also be used for non-relativistic velocities. We're more used to adding velocities like this : u' = u - v. This is exactly what the relativistic equation reduces to for velocities much less than the speed of light. The relativistic equation applies to any situation; the one we're used to is a special case that applies only for small velocities.

 

Read that last part again, it is important:  “The relativistic equation applies to any situation; the one we're used to is a special case that applies only for small velocities”.

 

The relativistic velocity addition equation is the General solution! We only use u’ = u – v in the special case that applies to small velocities much less than c!

 

Why are you insisting on use the special case for small velocities and applying it when the velocities are approaching a significant fraction of c?

 

 

Yea I'm the one who's wrong about this, good one. :)

 

 

 

Yes, you are and I have provided the sources that prove you are, but you will never learn.

 

There is never a velocity greater than c of an object relative to the observer! It doesn't apply to the velocity of other objects relative to each other. This is painfully obvious and the fact that you can't see it shows that you really have no business attempting to argue about a model that you clearly have no real understanding of.

 

 

Jesus Christ! Just read the above to see how wrong you are.

 

The remainder of your post is not worth responding to. You can choose to remain ignorant and arrogant, and if so, that is your problem, not mine.

 

Or you can learn something; your choice. At this point I could not care less what you do.

[billvon]

There is never a velocity greater than c of an object relative to the observer!

 

 

Jesus Christ! Just read the above to see how wrong you are.

He's quite right, actually.  What a strange thing to disagree with.