What do you know? e really does = MC Hammer squared

Calling all physicists.

I thought this was already proved:

PARIS (AFP) – It's taken more than a century, but Einstein's celebrated formula e=mc2 has finally been corroborated, thanks to a heroic computational effort by French, German and Hungarian physicists.

I can follow the story and I think I understand what was done and why it means what it means, although if you want to explain it in more detail or in a better way, I'd appreciate it.

My question is, why did I think e=mc2 had already been proved?  Was there a famous experiment that almost proved it?  Am I thinking of something else?  For instance, am I thinking that Michaelson-Morley proved more than was proved or was intended to be proved?

What did Michaelson-Morley prove and where were you when I was taking Dr Sundberg's physics final anyway?

For extra credit, explain the physics behind this:

Comments

[Ken Muldrew]

It's just press-release hype intended to help the scientists squeeze more money out of the government. Einstein's famous equation, e=mc^2, is really just a simple corollary to special relativity, so any experiment that supports the theory (basically the postulates that the speed of light is independent of the motion of the observer, and that the laws of physics are frame invariant), also supports the correctness of the equation. The Michaelson-Morley experiment supported special relativity over aether theories, so it also supported e=mc^2. Vast amounts of experimental results from the past century have also supported e=mc^2, and nothing has disproved it.

You can see Einstein's derivation in an English translation of his 1905 paper here . Just below the last equation he says that when energy is lost to radiation, then the mass decreases as L/c^2 (where L is energy). It's important to note that this paper appeared after Einstein's celebrated relativity paper (On the Electrodynamics of Moving Bodies). The famous equation is not foundational, it is a derived result.

The Hammer phenomenon is due to another result of relativity, namely that space and time are more properly treated as a 4 dimensional spacetime, thus when one states with intention, "stop...hammertime", the space inside one's pants inflates while time slows down momentarily. This hammers home the wisdom of using Clifford algebra as the natural language of relativity.

[Ken Muldrew]

I guess I should have read the article before commenting. What the scientists claim to have shown is that e=mc^2 is compatible with quantum chromodynamics (the theory of the strong nuclear force...quarks and all that). Not that anyone doubted it, but I guess it was hard to demonstrate. It has been known for ages that e=mc^2 was compatible with Lorentzian electrodynamics (Maxwell's equations + Newton's laws of motion) and quantum electrodynamics (the quantized theory of electrodynamics). And I think Fermi himself showed that e=mc^2 was compatible with the theory of the weak nuclear force (radioactive decay).

So the awful title of the article may just be due to a sloppy editor.

[Greg]

IIRC, the Michealson-Morley experiment predated Einstein. They were trying to prove the existence of the "ether" or determine some property of it, but it was producing counter-intuitive results. But the MM experiment demonstrated that the speed of light was constant, and Einstein later explained their results.

[Zodiac is good. Cryptonomicon is good. The rest? Well....]

Michelson-Morley showed that light waves weren't waves in an "aether" (or "ether") as some had postulated: they supposed that there was an ether underlying space, and that the earth was travelling through it at a non-trivial velocity. They then showed that light travelled at the same velocity in multiple directions, whereas if there was an ether underlying the universe, then light should travel faster when the earth was moving in one direction than in another (think going with the current versus going against the current: it is slightly misleading as an analogy, but instructive nonetheless).

This gave evidence that the Lorentz equations described the universe, leading ultimately to special and then general relativity. (Again, an oversimplification....)

N.

[Mike Schilling]

Alternatively, Michaelson-Morley might have demonstrated that the Earth is at rest with respect to the luminiferous ether, with the rest of the universe in motion around it. Copernicus was wrong!

The late Isaac Asimov suggested that the experiment be repeated on the Moon to disprove this. I don't think this has been done.

[Uncle Merlin]

I think you are correct Ken "The Hammer phenomenon is due to another result of relativity, namely that space and time are more properly treated as a 4 dimensional spacetime, thus when one states with intention, "stop...hammertime", the space inside one's pants inflates while time slows down momentarily. This hammers home the wisdom of using Clifford algebra as the natural language of relativity."

But you did not state the obvious, That the space inside one's pants is a very small dimension so Gluon Vacuum fluctuations come into play and the virtual particles interact with the fabric of the pants thereby creating that lovely billowing effect we see.