Daily Archives: August 10, 2010

I Would Gladly Pay You Tuesday for a Quantum Cheeseburger Today

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(Catching up on external posts on which I wanted to comment)

Uncertain Principles: Reader Request: Borrowing Energy

This gets answered in terms of the uncertainty principle in empty space. One thing Chad does not address here (to be fair, it was not explicitly part of the question) is that this is often asked and answered in the context of tunneling: You have a barrier of height V and an particle with KE < V, and yet the particle can be found to be on the other side of the barrier some fraction of the time. The answer is given that the particle borrows energy to get over the barrier, but it’s OK because the time is short. Unfortunately, that's the cheap way out.

The problem here is that "borrowing" energy is being used to explain a quantum phenomenon with a classical analogy. By borrowing energy the particle remains a particle and jumps the barrier in a nice classical way — the only quantum weirdness introduced here is the Heisenberg Uncertainty Principle. It's the kind of explanation given to people who have not been exposed to very much quantum physics, and it's semi-reassuring: the weirdness is limited to this whole uncertainty thing but all else is right with the world.

One of the physicists who posts to SFN (known as Severian) once remarked

Wave-particle duality is really just something we use to frighten children and undergraduates.

Funny, but I think this is actually backwards. It’s more like a Disney-fied story we tell to reassure undergraduates and non-physicists. You have the Disney happy ending that the world is still classical and we have a particle, which distracts from the original Brothers Grimm ending that no, these really are waves we are talking about, and yes, quantum mechanics is that strange.

Another Dimension to Add to Your Nightmares

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Radioactive Wild Boars Increase in Number

I wasn’t really all that concerned about wild boars, but now that I know they are radioactive and multiplying, a foul-tempered spider pig mutant becomes a terrifying idea. At least they aren’t zombie boars.

A couple of hiccups in the report

Although the radioactivity has been detected in other animals, such as birds, wild boar are more susceptible to contamination because they often eat mushrooms and truffles that absorb the harmful radioactivity. The radioactivity, in turn, can remain in the soil for years. In fact, levels in mushrooms and truffles are predicted to rise in the not too distant future.

Radioactivity isn’t a substance, it’s a process, so you don’t absorb radioactivity, nor is it left in the soil. (Iterations ofradioactive or radiation are almost universally preceded by harmful or dangerous. It’s apparently part of the pirate journalist code). But this (like heat) is a term that scientists will use carelessly, so it’s no wonder it propagates to the press, and I don’t take 10 points from Gryffindor for that.

Hunters aren’t idly standing by. They’ve found a concoction called Giese salt that supposedly causes wild boar to excrete radioactive substances after the animals have ingested the salt. Work performed in Bavaria, according to the Bavarian Hunting Federation, indicates the salt does the trick, presumably allowing the meat to pass government inspections.

One of the components in the salt strongly binds to the Cesium (or presumably any alkali), rather than just causing them to arbitrarily excrete any and all radioactive substances.

It’s already been 24 years since the Chernobyl nuclear disaster, but experts are predicting the problem of radioactive wild boars will plague Germany “for at least the next 50 years.”

The reason being that Cs-137 has a half-life of 30 years. Still, if boars are exhibiting 7000 Becquerel per kilogram (1 Bq is one decay per second. We physicists must have our unit names!), and if this is primarily from Cs-137 being ingested, this isn’t going to drop below 2,000 in 50 years much less the target of 600, unless some other process is present that will get rid of the Cs-137. Otherwise we’re talking 100 years.

Thou Shalt Not Dilate Thy Time

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For a long time I’ve thought that for all the anti-relativity crackpots there are, at least they are not driven by a religious ideology, thus sparing us the kind of battles that have to be fought to get evolution taught.

That’s apparently not the case anymore, though relativity still isn’t generally (or specially) taught in high school anyway, so school-board nonsense is avoided.

Conservapedia has an entry entitled Counterexamples to Relativity

The theory of relativity is a mathematical system that allows no exceptions. It is heavily promoted by liberals who like its encouragement of relativism and its tendency to mislead people in how they view the world.[1]

…

[1] See, e.g., historian Paul Johnson’s book about the 20th century, and the article written by liberal law professor Laurence Tribe as allegedly assisted by Barack Obama. Virtually no one who is taught and believes relativity continues to read the Bible, a book that outsells New York Times bestsellers by a hundred-fold.

I know that the religious right has a propensity for being anti-science, but I though at least they liked GPS. The maps and/or navigating algorithms may be occasionally wonky, but GPS works.

The list of “counterexamples” is interesting, and while I haven’t had time to follow up on all of them, there are a few head-scratchers as to why they should purportedly lead to relativity being wrong, and a few jaw-droppers, like

The inability of the theory to lead to other insights, contrary to every verified theory of physics.

That’s a serious case of denial (or should I say, bearing false witness). Relativity hasn’t led to other insights? It’s such a clue-deprived statement; it’s hard to respond to such a steaming load of stupid.

Several are trivially debunked, like the twins paradox objection, and the last one,

Relativity predicted that clocks at the Earth’s equator would be slower than clocks at the North Pole, due to different velocities; in fact, all clocks at sea level measure time at the same rate, and Relativists made new assumptions about the Earth’s shape to justify this contradiction of the theory.

Eisntein made this prediction in his 1905 paper [1], i.e. before he came up with general relativity. The oblate distortion of the earth changes the gravitational time dilation so that it is equal in magnitude to the kinematic term, but with an opposite sign. The shape of the earth is not an assumption, people measure it.

I would think this all a joke but for Poe’s law. These people haven’t a clue and are fiercely proud of it, which compels me to quote myself: I have never understood the phenomenon of wearing one’s ignorance as a badge of honor.

[1] Update: In the paper (On the Electrodynamics of Moving Bodies) he specifically states that it holds for a rigid sphere.

The stupid, it burns.

Update II: Takedown at Skulls in the Stars

Update III: more from me on the subject