# Thread: On Einstein's explanation of the invariance of c

1. Originally Posted by Neddy Bate
This may sound unbelievable, but I think Motor Daddy's universe is actually more complicated than relativity! He's got light doing all sorts of odd things because of the "absolute velocities" of different reference frames. I mean, the earth is a ROTATING frame, for gosh sakes. The speed of light would vary by time of day, as well as seasonally, etc. Trying to get any physics done would be a nightmare. It would be chaos! lol
Like I said before, admit mine is correct and I'll admit Einstein's is incorrect but easier.

I thought it was widely understood that the Earth is a rotating frame.

2. Originally Posted by Motor Daddy
I'm not a mathematician
Check.
You aren't a physicist either, or much of a logician.

But, hey, since you can add and subtract, Einstein must have got it wrong . . . everyone knows how useless he was with math.

3. Originally Posted by arfa brane
Check.
You aren't a physicist either, or much of a logician.

But, hey, since you can add and subtract, Einstein must have got it wrong . . . everyone knows how useless he was with math.
Always ready to get a cheap shot in, eh? Instead of talking trash why don't you look at post #912 and tell me where I go wrong?

4. You go wrong when you assume that understanding how to add and subtract means you can understand special relativity.

Post #912 without even looking at it, is guaranteed to be a repeat of every other post you've made in this thread. I rest my case.

5. Originally Posted by arfa brane
You go wrong when you assume that understanding how to add and subtract means you can understand special relativity.

Post #912 without even looking at it, is guaranteed to be a repeat of every other post you've made in this thread. I rest my case.
I'll take that to mean you just think it's wrong, but you can't tell me why. You do a lot of that.

6. I can see that it's wrong, and I can explain why. So can more than a few other people.

You can't answer questions or accept that your logic is almost totally flawed--you still don't seem to understand things that you've said you do understand, for instance what a stationary frame is, what an observer is, and so on. Even what a clock is and how to synchronise one. You do a lot of that.

7. Originally Posted by arfa brane
I can see that it's wrong, and I can explain why. So can more than a few other people.
Well get hot! What are you waiting for? Let me have it. Tell me where I go wrong.

8. The most obvious mistake you keep repeating is this: you ignore any questions, and just go over the same old ground as if everbody who has read it 900 times already needs to see it again.

I could trawl back over the thread and quote some of the questions you have ignored, or not attempted--this is the telling part, it's more than a possibility that you simply don't understand them, or you just don't know the answer or if there is an answer.

But that would be a big waste of time, because you'll just ignore them all over again. It was fun, even a bit of a laugh, but now it's more like finding out someone dropped their ciggy butt into your can of beer.

9. Originally Posted by Motor Daddy
I don't understand what you mean by drawing a right triangle and having light travel faster than c. Can you show me in a pic what you are talking about? I'm not a mathematician, so if there is something I've done wrong in my formula by all means, let me know how to fix it so that it represents my theory correctly.

I'll try to draw something, but in the meantime, here is a verbal explanation. Lay down a tape measure on the "floor" of the absolute rest frame. Now lay another tape measure down at a right angle to the first one. Call the measurements on one of the tape measures "x" and call the measurements on the other tape measure "y". When the train moves, we will use "x" to measure how far the train moves. We will use "y" to measure how far the skate moves, because the skate travels a path that is 90 degrees to the path of the train.

Let's start with the skate located at position (0,0) where the first zero is the "x" value, and the second zero is the "y" value. For this exercise, let's say that only the train moves, and the skate just sits still inside the train. In this case, let's say that the skate moved from (0,0) to (12,0) because of the movement of the train. Notice that the skate has moved a distance of 12. I am just making these numbers up for this simple exercise.

Now let's try things a little differently. This time, let's say that only the skate moves, and the train stays motionless. In this case, let's say that the skate moved from (0,0) to (0,8) because of the movement of the skate. Notice that the skate has moved a distance of 8 for this case. Again, I'm just making these numbers up.

And finally, let's combine both motions together. We will let the skate move at the same time as the train moves. In this case, the skate moves from (0,0) to (12,8) because of the movement of the skate and the train combined. As you can see, the skate has moved in both the "x" and "y" directions. If there had been an elevator on the train, the skate could also have also moved along the "z" direction, but let's keep things simple for now.

Anyway, do you know how to calculate how far the skate moved? If not, here is the answer:
d = sqrt(12^2 + 8^2)
d = sqrt(144 + 64)
d = sqrt(208)
d = 14.422
In case you don't know those symbols, the "sqrt" means square root, and the "^2" means raised to the second power. Raising to the second power is also called squaring, which is just another way of saying that the number is multiplied by itself.

If we want to talk about the "absolute velocity" of the skate, then we must consider that it actually traveled a distance of 14.422, because it went from point (0,0) to point (12,8). The line that connects those points is the vector that represents the direction of the absolute velocity.

Now let's get to some light signals. If the skate has a length of 1, and a beam of light travels the length of the skate, how far does the light travel according to the absolute rest frame? Here is the answer:
d = sqrt(12^2 + 9^2)
d = sqrt(144 + 81)
d = sqrt(225)
d = 15

The reason I used 9 instead of 8 is because I added the length of the skate to the "y" dimension. The vector that represents the direction of the velocity of the light is the line that goes from point (0,0) to (12,9). This is the information that I have been using to show that your calculations are not working with a light speed of "c" in the absolute rest frame. Does this make sense yet?

10. Originally Posted by arfa brane
The most obvious mistake you keep repeating is this: you ignore any questions, and just go over the same old ground as if everbody who has read it 900 times already needs to see it again.

I could trawl back over the thread and quote some of the questions you have ignored, or not attempted--this is the telling part, it's more than a possibility that you simply don't understand them, or you just don't know the answer or if there is an answer.

But that would be a big waste of time, because you'll just ignore them all over again. It was fun, even a bit of a laugh, but now it's more like finding out someone dropped their ciggy butt into your can of beer.
Post #912 demolishes Einstein's concept of the relativity of simultaneity. You think it's wrong? SHOW ME!!! Enough of the small talk, SHOW ME!!!

11. Well I would, but Oprah is on, so there are more better things to do . . .

Post #912 demolishes Einstein's concept of the relativity of simultaneity.
You really do have a tiny little brain, don't you?

12. Originally Posted by Neddy Bate
I'll try to draw something, but in the meantime, here is a verbal explanation. Lay down a tape measure on the "floor" of the absolute rest frame. Now lay another tape measure down at a right angle to the first one. Call the measurements on one of the tape measures "x" and call the measurements on the other tape measure "y". When the train moves, we will use "x" to measure how far the train moves. We will use "y" to measure how far the skate moves, because the skate travels a path that is 90 degrees to the path of the train.

Let's start with the skate located at position (0,0) where the first zero is the "x" value, and the second zero is the "y" value. For this exercise, let's say that only the train moves, and the skate just sits still inside the train. In this case, let's say that the skate moved from (0,0) to (12,0) because of the movement of the train. Notice that the skate has moved a distance of 12. I am just making these numbers up for this simple exercise.

Now let's try things a little differently. This time, let's say that only the skate moves, and the train stays motionless. In this case, let's say that the skate moved from (0,0) to (0,8) because of the movement of the skate. Notice that the skate has moved a distance of 8 for this case. Again, I'm just making these numbers up.

And finally, let's combine both motions together. We will let the skate move at the same time as the train moves. In this case, the skate moves from (0,0) to (12,8) because of the movement of the skate and the train combined. As you can see, the skate has moved in both the "x" and "y" directions. If there had been an elevator on the train, the skate could also have also moved along the "z" direction, but let's keep things simple for now.

Anyway, do you know how to calculate how far the skate moved? If not, here is the answer:
d = sqrt(12^2 + 8^2)
d = sqrt(144 + 64)
d = sqrt(208)
d = 14.422
In case you don't know those symbols, the "sqrt" means square root, and the "^2" means raised to the second power. Raising to the second power is also called squaring, which is just another way of saying that the number is multiplied by itself.

If we want to talk about the "absolute velocity" of the skate, then we must consider that it actually traveled a distance of 14.422, because it went from point (0,0) to point (12,8). The line that connects those points is the vector that represents the direction of the absolute velocity.

Now let's get to some light signals. If the skate has a length of 1, and a beam of light travels the length of the skate, how far does the light travel according to the absolute rest frame? Here is the answer:
d = sqrt(12^2 + 9^2)
d = sqrt(144 + 81)
d = sqrt(225)
d = 15

The reason I used 9 instead of 8 is because I added the length of the skate to the "y" dimension. The vector that represents the direction of the velocity of the light is the line that goes from point (0,0) to (12,9). This is the information that I have been using to show that your calculations are not working with a light speed of "c" in the absolute rest frame. Does this make sense yet?
I understand what you are telling me. I was measuring the distance the skate traveled inline with the train's motion, not at 90 degrees to the train's motion.

There is two different velocities we are talking about here, one of the train and one of the skate. The two velocities are separate. The train in the direction of the tracks, and the skate in the direction 90 degrees to the tracks. The velocity of each light is in the direction of the object's motion.
So, there is an x velocity and a y velocity. They are separate velocities. You can't combine them and say the skate arrived at (12,9) like it traveled in a straight line from (0,0). There are two separate velocities, one of the x and one of the y.

13. Originally Posted by Motor Daddy
I understand what you are telling me. I was measuring the distance the skate traveled inline with the train's motion, not at 90 degrees to the train's motion.

There is two different velocities we are talking about here, one of the train and one of the skate. The two velocities are separate. The train in the direction of the tracks, and the skate in the direction 90 degrees to the tracks. The velocity of each light is in the direction of the object's motion.
Are you disputing that light traveled from point (0,0) to point (12,9)?

14. Originally Posted by Neddy Bate
Are you disputing that light traveled from point (0,0) to point (12,9)?
The x has a velocity and the y has a velocity.

If light is emitted from a light sphere, how does light get to 12,9 in a straight line in each direction from the center of the sphere? Impossible for one light to get to 12,9 at the same time.

15. Originally Posted by Motor Daddy
The x has a velocity and the y has a velocity.
Don't you think that ray of light should go from (0,0) to (12,8) at exactly 299,792,458 m/s as measured from the absolute rest frame?

16. Originally Posted by Motor Daddy
If light is emitted from a light sphere, how does light get to 12,9 in a straight line in each direction from the center of the sphere? Impossible for one light to get to 12,9 at the same time.
There is only one light ray. It travels down the skate. If the speed of the skate and the speed of the train are the same, then the light coordinate would have the form (12,12) or (9,9). But in this, case I chose for the train and the skate to have different speeds.

17. Originally Posted by Neddy Bate
Don't you think that ray of light should go from (0,0) to (12,8) at exactly 299,792,458 m/s as measured from the absolute rest frame?
Think of a light source in space, like a small sun. Each ray of light travels away from the source in a straight line. There is one distance the light travels. It is impossible for light to leave a source and travel to 12,9. It either travels 12 away, or 9 away, depending on the time.

18. Originally Posted by Motor Daddy
Think of a light source in space, like a small sun. Each ray of light travels away from the source in a straight line. There is one distance the light travels. It is impossible for light to leave a source and travel to 12,9. It either travels 12 away, or 9 away, depending on the time.
You don't think I can shine a laser pointer from (0,0) to point (12,8) in the absolute rest frame? You dont think a sphere of light set off at point (0,0) will eventually cross the point (12,9)?

Wow.

If the train had not moved, and the skate had not moved, the light would have traveled from (0,0) to (0,1). Do you dispute this simple concept?

19. Originally Posted by Neddy Bate
You don't think I can shine a laser pointer from (0,0) to point (12,8) in the absolute rest frame? You dont think a sphere of light set off at point (0,0) will eventually cross the point (12,9)?
What point 12,8 in what absolute rest frame? Do you think there is some kind of grid system in space?

Light defines space in straight lines.

20. Originally Posted by Motor Daddy
What point 12,8 in what absolute rest frame? Do you think there is some kind of grid system in space?
Are you telling me I canNOT make length measurements in your absolute rest frame?