Absolute Space

Einstein's work makes sense.

I don't understand anything about Don's answer.

Would someone other than Don tell us what the heck he is trying to say?

This bite of realism brought to you by "Gadfly."

Don writes re the Michelson Morley experiment:

M/M could find no evidence of a change in the speed of light no matter what direction their apparatus was aimed. This is an indication that the earth is motionless relative to absolute space and light will travel at the same rate no matter which direction it travels.

The boldface clause is incorrect.

I promised myself not to get involved in long discussions of misguided science, but I guess I just have to speak my piece and leave.

So here's my one comment on the discredited idea of absolute space, a.k.a. the ether. There is no such thing. It is not necessary to explain the universe as we know it. All motion is relative. There is no privileged frame of reference. And even if there was such a frame, it is nonsense to assume that it is the frame of an insignificant planet of a slightly larger than average star in an ordinary galaxy, which is what the bold words are stating.

The following is from pp.12-13 of my Physics: Decade by Decade (Twentieth-Century Science series, Facts On File, 2007).

...they tried to detect slight differences among the speeds of light beams that travel along the direction of Earth's motion, opposite to that direction, and perpendicular to that direction. Very sensitive measurements failed to find any differences at all. Some people interpreted the failure to detect such differences as evidence that the ether does not exist. Einstein went a step farther. He said that the nonexistence of the ether means that the universe has no absolute frame of reference. The motion of one object or wave can only be measured relative to another, but not with respect to the universe itself.

Einstein's view of relativity was a natural extension of earlier scientific thought. At first, people viewed the Earth as the unmoving center of everything. Then they realized that Earth was one planet moving in a larger solar system. The natural human reaction was then to place the Sun at the center of the universe. But by Einstein's time, astronomers could tell that the stars were moving with respect to one another. They no longer had reason to think that the Sun -- or any other star -- occupied a special place in the universe. From that perspective, it was easier to give up the idea of an absolute frame of reference.

That led Einstein to state this basic principle of physics: If two observers are moving at constant velocity with respect to one another, neither observer's frame of reference is preferable to the other's. It is impossible to make any observation that determines that one is moving while the other is absolutely at rest in the universe.

That simple principle produces some surprising consequences. As noted in the Introduction, Maxwell's equations predict the existence of electromagnetic waves that travel at a definite speed. That means that two observers, regardless of their relative motion, must measure the same speed for a beam of electromagnetic radiation.

[The above is copyrighted material, and it's appearance here does not grant the privilege to distribute it further without my permission.]

I will not reply further. But such awful misinterpretation of centuries of understanding gets my goat.

No, Don, our planet is not stationary in a privileged frame of reference. In fact, it is not stationary in any inertial frame of reference. The work of Copernicus, Galileo, and Newton tells us that. You are not only rejecting Einstein but also several centuries of science before that!

Fred Bortz -- Science and technology books for young readers (www.fredbortz.com) and Science book reviews (www.scienceshelf.com)