Some points i didnt understand well.

[Seventh cavalry]

I finished the book well, because i understood the theory briefly before i read it, i can't understand the old theory that dominated the physics in 1800s the ether wind theory. So can some good people help me understand it ?

 

 

 

 

I didn't really get the Mach's principle , ether wind theory, and in the book says so much how stuff can't travel faster or at speed of light, but a pair of huge scissors can because it is moving on a geometric point, i didn't get that. It was kind of confusing for me to read a English book because I'm Chinese.

 

 

 

 

and last question, in the book it stated that in a space ship traveling at high speed, lets say 50% speed of c. lets say the ceiling and floor of the rocket is parallel, and a light bulb's from ceiling is going down strait. and reflect up. and it said 2 observer is different. The guy inside see a light go down and up | just like this, but someone out side not moving will see the light go like this \ and reflect up / Yes i understand because the space ship is moving at the same time, but it is because that the time is passing slower for him but the light is constant so this is possible or opposite ?

 

 

 

 

 

 

 

 

[Joatmon]

..........................................................I didn't really get the Mach's principle , ether wind theory, and in the book says so much how stuff can't travel faster or at speed of light, but a pair of huge scissors can because it is moving on a geometric point, i didn't get that. It was kind of confusing for me to read a English book because I'm Chinese............................................

 

I haven't read the book, but I wonder if this point is what I aired in #21 in the topic "Change and time". The point I tried to make was either not understood or not accepted. I repeat the relevant part of my post:-

 

"By the same argument consider a long pair of scissors. As you close the blades you will see the point of intersection travel along the blades faster than the speed the handles are pulled together. Now, consider a pair of scissors so designed that the two blades come together at the same time for their whole length. Could you not say the point of intersection travels instantaneously from one end to the other? "

 

Note, nothing actually moves along the point of intersection - its just a pattern with no substance.

 

 

 

 

[Aethelwulf]

I finished the book well, because i understood the theory briefly before i read it, i can't understand the old theory that dominated the physics in 1800s the ether wind theory. So can some good people help me understand it ?

 

 

 

 

I didn't really get the Mach's principle , ether wind theory, and in the book says so much how stuff can't travel faster or at speed of light, but a pair of huge scissors can because it is moving on a geometric point, i didn't get that. It was kind of confusing for me to read a English book because I'm Chinese.

 

 

 

 

and last question, in the book it stated that in a space ship traveling at high speed, lets say 50% speed of c. lets say the ceiling and floor of the rocket is parallel, and a light bulb's from ceiling is going down strait. and reflect up. and it said 2 observer is different. The guy inside see a light go down and up | just like this, but someone out side not moving will see the light go like this \ and reflect up / Yes i understand because the space ship is moving at the same time, but it is because that the time is passing slower for him but the light is constant so this is possible or opposite ?

 

 

 

Someone else started a thread on Aether Theory.

 

Many people said it was ''proven wrong''.... That is not true. The old classical theory of Aether was proven wrong - this does not mean an Aether does not exist. In a recent conversation with someone, it was made apparent to me that there could be a ''quantum Aether.''

 

In your case, the wind Aether, is like a dragging effect on time, much as a syth rakes through an old mans crops. An object in the classical version would do much the same thing - it would plow through spacetime dragging the background energies with it. I believe it is this type of ''wind'' that was hoping to be observed. The idea came about from the Luminiferous Aether and it described the motion of particles in a medium of light particles.

[IM Egdall]

quote name='Seventh cavalry' timestamp='1340042139' post='685009']

I finished the book well, because i understood the theory briefly before i read it, i can't understand the old theory that dominated the physics in 1800s the ether wind theory. So can some good people help me understand it ?

 

 

In the nineteenth century, physicists believed that electromagnetic radiation (like visible light) had to propagate through some kind of medium -- which they labeled the ether. (Just like sound must travel through some kind of medium like air. In a vacuum, there is no sound.) They believed this ether permeated all of space.

 

But in 1905, Einstein declared that there is no ether -- electromagnetic waves travel through empty space.

 

and last question, in the book it stated that in a space ship traveling at high speed, lets say 50% speed of c. lets say the ceiling and floor of the rocket is parallel, and a light bulb's from ceiling is going down strait. and reflect up. and it said 2 observer is different. The guy inside see a light go down and up | just like this, but someone out side not moving will see the light go like this \ and reflect up / Yes i understand because the space ship is moving at the same time, but it is because that the time is passing slower for him but the light is constant so this is possible or opposite ?

 

 

I think the idea is this. Light always travels at the same speed, c (about 670 million miles an hour). This leads to time dilation:

 

From the view of someone inside the moving rocket, the light beam goes from the ceiling to the floor and back in a straight vertical line.

 

But to someone at rest outside the moving rocket, the light beam must take a diagonal path to go from the ceiling to the floor and back to the ceiling. And this diagonal path is a longer path. But the light is still traveling at c. So the light traveling at the same speed takes a longer time to go from ceiling to floor to ceiling. Thus to the person at rest outside the moving rocket, time is running slower on the rocket (than for the person inside the rocket).

 

 

I hope this helps.

Edited June 18, 2012 by IM Egdall