Sane Clown Posse Time

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Vertiasium and Minute Physics team up to explain magnets.

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I was worried for a minute they were going to leave it at “magnets behave that way because electrons behave like tiny magnets” which only moves the goalposts, but there’s a nice reality check there, and it’s good even though they don’t delve too much into the quantum — they gloss over that it’s related to spin, and also lean a little on the Bohr description of the orbital motion. (IOW, it’s not that the orbital motion cancels, per se, it’s that there are no classical trajectories to begin with.

I saw this at It’s Okay to be Smart, and in a followup I think that Joe is right when he claims that when Feynman says (in the last video in the link) he can’t explain magnets, he’s not actually saying he can’t explain what the videos covered — he actually does (briefly) mention the answer. He’s explaining why “why” questions are difficult in physics — we always hit that point (mentioned in the video above) where you have to say “No-one knows. That’s just the way the universe works”.

Floating Some Ideas

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What It’s Like To Spend 55 Days in Space

Moreover, it’s not clear that private space initiatives are the answer to the problem. “Space exploration is not an immediate payback, fiscally or otherwise,” Ivins says. “It is a generational kind of investment. And the only group that can afford to make that kind of an investment is a government.”

This is not exclusive to NASA, it’s true of research in general.

Plus, for the benefit of geeks across the universe, Ivins explains why the Borg cube from Star Trek can maneuver just as well as any starfighter that Hollywood has ever dreamed up. “In space, they’re one and the same,” says Ivins.

This is probably the one bit of science that space-based science fiction gets pretty consistently wrong — that maneuvering a craft in space would be anything like a plane or even a submarine. Most of the time the engine exhaust only points to the rear, and the engines are firing even when traveling at constant speed. Which is wrong even before you get to the fancy maneuvering.

Knock Me Down With a Feather*

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*Knocking me down with a feather is not intended to diagnose, treat, cure or prevent disease.

Copper Bracelets, Magnetic Wrist Straps Fail to Help Rheumatoid Arthritis

I had noted a long time ago that based on the proposed mechanism, there was no basis to expect magnetic bracelets to work. No real surprise that they don’t.

The research published in PLOS ONE, show that both the standard magnetic wrist strap and the copper bracelet provided no meaningful therapeutic effects beyond those of a placebo, which was not magnetic and did not contain copper.

I like that they point this out about the placebos.

Getting to the Next Level Down?

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A Jewel at the Heart of Quantum Physics

I have no way to evaluate this. This could be overselling a new idea or they could be onto something. If there’s a geometric way of expressing scattering probabilities, great. I suppose it’s possible to view Feynman diagrams as expansion terms of some function, so if they’ve found a way to figure out the underlying function, that’s wonderful. Amplituhedron seems a tad cute, but then I’m in a sub-field where someone made up Bosenova, so atomic physics doesn’t exactly have the high moral ground here.

One thing that gives me pause is any claim that they have discovered any “true” nature of anything. Like all of physics, we are talking about models. Physics describes how nature behaves, not what it really is.

19th Century Physics for $400, Alex

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What are Maxwell’s Equations?

At first glance it’s pretty good, although there are one or two things I think aren’t expressed well. One is the divergence of E equation. It’s written as being equal to zero, with the explanation that this is true when there are no charges arund. Well, the other form that’s discussed,

\(\nabla\cdot{\bf E} = \rho/\epsilon_{\tiny 0}\)

is always true. If there are no charges around, rho is zero. I’m not a big fan of equations that are written for specific cases. The first thing that happens is you forget the assumptions and caveats, and then when you try to apply it in general, it fails to work. Use the general equation and then apply the boundary conditions. You’ll be better off in the long run.

Then there is this canard:

Longer wavelengths include heat (infra-red waves)

No! Heat is NOT a part of the EM spectrum. It’s true that for room-temperature items and thereabouts, the bulk of the energy radiated is in the infrared part of the spectrum, but not all IR is from thermal sources, so equating the two is wrong. Furthermore, when you get hotter, you start getting visible light. Like from a stove burner or the sun — all of that light we can see? It’s still radiant heat!

I Don't Like Mondays

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Today was a Very Bad Day™, in a depressingly long and growing list of Very Bad Days™. And while there are bound to be proclamations of “it’s too soon to talk about the implications” countered by “if not not now, when?” and so forth, and also some shooter(s) was/were (religion) and (ethnicity) and this has profound implications because of (generalization and/or inappropriate extrapolation), that discussion really doesn’t interest me right now, because we don’t know everything yet.

Of more immediate import to me is the one certain fact: that we don’t know everything yet. That was true all day, as the stories poured out — they were sketchy and often wrong. One shooter, two shooters, three shooters — the number kept changing. One shooter was down, and then that was withdrawn, and then confirmed, but nobody could say if “down” meant dead or arrested. Shooting at Bolling AFB was reported, and then dismissed as being false.

Information dissemination is fast. Twitter and internet news were reporting this very soon after it started. Information collection is slow, and since it’s also imperfect it requires confirmation, making it even slower. And this is one things that tends to get glossed over in the aftermath. That while all of this was going on, we didn’t really know what was happening. It was true after the Boston Marathon bombing and manhunt, and it was true in all of the other incidents before that. If you are going to get involved in any sort of discussion, don’t fall prey to the notion that anyone had more than scant knowledge, or that anything about this should have been obvious. That’s hindsight bias.

(one note, since you may not be familiar with DC at all: I don’t work at the navy yard. Emotions aside, in the grand scheme of things this event only had a minor impact on my day, in that we were in a heightened security situation)