Purported Relativity Paradox Resolved

sciencehabit writes "A purported conflict between the century-old theory of classical electrodynamics and Einstein's theory of special relativity doesn't exist, a chorus of physicists says. Last April, an electrical engineer claimed that the equation that determines the force exerted on an electrically charged particle by electric and magnetic fields — the Lorentz force law — clashes with relativity, the theory that centers on how observers moving at a constant speed relative to one another will view the same events. To prove it, he concocted a simple 'thought experiment' in which the Lorentz force law seemed to lead to a paradox. Now, four physicists independently say that they have resolved the paradox."

Comments

Re:Dark matter

[buchner.johannes]

So, hidden momentum and dark matter... What other concept will we invent to explain we dont know anything?

Dark matter is not an invented concept, it is a name for something we observe. Galaxies just rotate faster than from what is there in normal matter. So something is going on, and this something is called "dark matter", just because it does not produce/interact with light but behaves like a mass.

Now in what way you explain this (new physical laws, new elementary particles) is still an open question. But it's there and needs to be addressed. Dark matter is just the name of the problem.

Re:Cognition

[thegreatemu]

Not by any means. For probably the best example, look at the Einstein-Rosen-Podalsky paradox , a simple thought experiment used an attempt to disprove the so-called Copenhagen interpretation of quantum mechanics because it would require the instantaneous transmission of quantum states in such a way that would violate special relativity. People did try to think their way out of it, until Bell's theorem "thought" everyone back into the paradoxical corner - leading to the modern sciences of quantum entanglement.

In fact if you look back, many of the advances in modern physics have come about specifically because of paradoxes arising from thought experiments. See also the ultraviolet catastrophe, or even Schrodinger's cat for that matter.

Re:Dark matter

[Omnifarious]

Observations of the gravitational lensing caused by far away galaxies in the process of merging have distinctly shown concentrations of something that's lensing the light that's not in either of the two galaxies. There are also other observations that kill any possible 'alternate law of gravity' explanations.

I thought these explanations were interesting myself and I've been paying attention to the topic. And there's been a lot of study of these ideas, because you're right, positing a brand new form of matter is a big step. And study leads to experiments. And the experiments have lead to the general consensus is that dark matter has to be something that has mass and doesn't otherwise interact with light (or normal matter) at all.