Could the ether be the same as the dark matter scientists cannot find?
An emailer asks whether the traditional ether could be one and the same as the dark matter modern astronomers need but cannot find.
Answer
No, the ether traditionally known as ether is not the same thing as dark matter. Dark matter is an invention they need, because almost all the spiral galaxies they examine are rotating too fast to agree with Newton's law, F equals MA, for the amount of mass they have. They cannot slow the galaxy down, so they need more mass, but each galaxy only has the visible mass of its stars. Rather than revamp Newton's laws, and with them Einstein's field equations, they invented dark matter: matter that does not reflect light, that they need but have never found. Ether is a completely different idea, going back to the scientists of the 1800s and the Greeks: there must be something filling all space, because nothing cannot exist; if there were truly nothing between the earth and the sun, they would coalesce. And unlike dark matter, the ether has been found. Einstein declared there was no ether in special relativity, but in quantum mechanics, when you pound on space with spectroscopic instruments, you can kick out a particle of it, the electron-positron dipole predicted by Paul Dirac in 1928 and discovered by Carl Anderson four years later. So you have two totally different reasons for the missing mass, and the ether has actually been found, while dark matter has never been seen.