Einstein relativity question.

[deltapapha]

I run a facebook group where about 20 friends I've known over the years raise some interesting topic for debate or discussion. One recent post was this: "Relate the first time you had relativity explained to you and understood it enough to have your mind blown."

After a couple of replies one gentleman wrote this, (and here is my question specifically). Is there anything wrong with what he wrote here? Does time dilation involve vectors and direction as well as magnitude?

[EDIT: I know it involves magnitude but was just wondering if direction was involved]

Here is his comment:

"As for the concept of time dilation, it's one and the same with the relativity of motion. The speed of light is constant, yes, which is a mind-blowing concept all by itself. But the velocity of light is not constant, since velocity is a measure of speed and direction, and consequently distance.

If a beam of light were shot up from a mirror lying flat on the floor of the train, to hit a mirror directly above it level with the ceiling of the train, an observer on the train would observe the light beam moving straight up and down. But an observer from outside the train would see the light beam moving diagonally. Thus, to the observer, the light beam, moving at the same speed for both observers, would appear to the observer outside the train to take a longer amount of time to bounce between the two mirrors. Even though the speed of light is the same for both, the velocity and distance covered are different."

 

[IloveTHIS]

I'm going to get really drunk and take a crack at this brb

 

[facePuncher7]

I thought a vector inherently had a magnitude, at the very least implied by the distance between its 2 defining points.

I'm approaching this from a geo-science/programming background though so the context may alter the meaning in a way I'm unaware of.

 

[TankAbbott4Eva]

I thought a vector inherently had a magnitude, at the very least implied by the distance between its 2 defining points.

I'm approaching this from a geo-science/programming background though so the context may alter the meaning in a way I'm unaware of.

A vector has magnitude and direction by definition. I never really understood relativity though, learnt about it but never actually got it, could do the questions though.

 

[facePuncher7]

Ok I actually finished reading.

So in that context, you're defining the perceptual differences between what I would call local space and world/global space.

Relative to the space defined by the train, of which the mirrors are to be considered "child objects", and then the light being a child of the mirrors, the magnitude never changes, and nor does the vector. This is because the heirachy of inherited vectors is static. Wherever the train is, positionally and rotationally, the light is also.

In world space however, of which the train is a child though not statically bound in position and rotation, the vector of the light can change, but not the magnitude.

 

[deltapapha]

I thought a vector inherently had a magnitude, at the very least implied by the distance between its 2 defining points.

I'm approaching this from a geo-science/programming background though so the context may alter the meaning in a way I'm unaware of.

right, I should have just asked, does time dilation involve direction for its results? Or is it just all scalar?

 

[facePuncher7]

right, I should have just asked, does time dilation involve direction for its results? Or is it just all scalar?

I'm not so knowledgeable yet about time, but I would assume it is treated as a scalar value in all but experimental models.

 

[TheMadThinker]

 

[rj144]

What is your question?

 

[90 50]

It never changes, only the persons perception changes.

The persons perception is only our brains interpretation of the light, not the actual light.

In both cases the light does not change, not the speed, not the direction , or the velocity.

 

[rj144]

It never changes, only the persons perception changes.

The persons perception is only our brains interpretation of the light, not the actual light.

In both cases the light does not change, not the speed, not the direction , or the velocity.

Light does change direction. It's not perception.

 

[rj144]

Time is a scalar. Direction has nothing to do with time dilation.

Length contraction is associated with direction.

 

[90 50]

Light does change direction. It's not perception.

No the light does not change, the light moves the way it does. One persons perception of it being different from another’s does not change the light

You don’t know enough about light if you think that.

 

[Chappi]

I've seen that experiment with the train done on some science tv show.
You could actually see a 1 or 2 second delay depending on the point of view of the observer, it was pretty cool to see it.

 

[deltapapha]

Time is a scalar. Direction has nothing to do with time dilation.

Length contraction is associated with direction.

Where is my friend going wrong in this statement. Obviously he has a lot correct but it seems like there is some point that he might be missing about why time dilation is so mind blowing.


here is is comment:
""As for the concept of time dilation, it's one and the same with the relativity of motion. The speed of light is constant, yes, which is a mind-blowing concept all by itself. But the velocity of light is not constant, since velocity is a measure of speed and direction, and consequently distance.

If a beam of light were shot up from a mirror lying flat on the floor of the train, to hit a mirror directly above it level with the ceiling of the train, an observer on the train would observe the light beam moving straight up and down. But an observer from outside the train would see the light beam moving diagonally. Thus, to the observer, the light beam, moving at the same speed for both observers, would appear to the observer outside the train to take a longer amount of time to bounce between the two mirrors. Even though the speed of light is the same for both, the velocity and distance covered are different."

 

[rj144]

No the light does not change, the light moves the way it does. One persons perception of it being different from another’s does not change the light

You don’t know enough about light if you think that.

I would say I do. It's called quantum mechanics.

 

[rj144]

Where is my friend going wrong in this statement. Obviously he has a lot correct but it seems like there is some point that he might be missing about why time dilation is so mind blowing.


here is is comment:
""As for the concept of time dilation, it's one and the same with the relativity of motion. The speed of light is constant, yes, which is a mind-blowing concept all by itself. But the velocity of light is not constant, since velocity is a measure of speed and direction, and consequently distance.

If a beam of light were shot up from a mirror lying flat on the floor of the train, to hit a mirror directly above it level with the ceiling of the train, an observer on the train would observe the light beam moving straight up and down. But an observer from outside the train would see the light beam moving diagonally. Thus, to the observer, the light beam, moving at the same speed for both observers, would appear to the observer outside the train to take a longer amount of time to bounce between the two mirrors. Even though the speed of light is the same for both, the velocity and distance covered are different."

Did he derive it himself? In the derivation, it's the relative velocity between inertial reference frames that matters. But, time is still a scalar.

 

[90 50]

I would say I do. It's called quantum mechanics.

Yeah yeah yeah what ever.

The point is the light is not changing. There are two different perceptions , but the light doesn’t itself change. M

The light doesn’t care or know how many people from how many angles are watching it, it moves at the same speed direction and velocity every time.

Doesn’t matter if a bear shitting in the woods the train passes observes it at a different angle also, the light doesn’t give a shit and doesn’t change

There’s no add on to the inverse square law for bears in the woods shitting

 

[rj144]

I've seen that experiment with the train done on some science tv show.
You could actually see a 1 or 2 second delay depending on the point of view of the observer, it was pretty cool to see it.

A 1 or 2 second delay? Were the mirrors kilometers apart or was the train moving at 95% the speed of light?

 

[rj144]

Yeah yeah yeah what ever.

The point is the light is not changing. There are two different perceptions , but the light doesn’t itself change. M

The light doesn’t care or know how many people from how many angles are watching it, it moves at the same speed direction and velocity every time.

Doesn’t matter if a bear shitting in the woods the train passes observes it at a different angle also, the light doesn’t give a shit and doesn’t change

There’s no add on to the inverse square law for bears in the woods shitting

You have no idea what you're talking about. How do you think a lens focuses?