Fool Me Once …

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Neutrinos Travel Faster Than Light, According to One Experiment

I chose this particular link because of the headline, specifically the addendum According to One Experiment. If it’s not reproducible, then it will go down in the annals of science as a fluke measurement.

[T]he result would be so revolutionary that it’s sure to be met with skepticism all over the world. “I suspect that the bulk of the scientific community will not take this as a definitive result unless it can be reproduced by at least one and preferably several experiments,” says V. Alan Kostelecky, a theorist at Indiana University, Bloomington. He adds, however, “I’d be delighted if it were true.”

It’s important to note that the experimenters are not claiming to have overturned relativity and are calling for independent confirmation. If you read otherwise, that’s the journalists or editors trying to show some scientific cleavage.

Another reason I chose this article was that they mentioned how the timing was done, because that’s a likely candidate for introducing error.

Jung, who is spokesperson for a similar experiment in Japan called T2K, says the tricky part is accurately measuring the time between when the neutrinos are born by slamming a burst of protons into a solid target and when they actually reach the detector. That timing relies on the global positioning system, and the GPS measurements can have uncertainties of tens of nanoseconds. “I would be very interested in how they got a 10-nanosecond uncertainty, because from the systematics of GPS and the electronics, I think that’s a very hard number to get.”

Some other commentary: This Extraordinary Claim Requires Extraordinary Evidence!

Update: Here is the CERN press release

Given the potential far-reaching consequences of such a result, independent measurements are needed before the effect can either be refuted or firmly established. This is why the OPERA collaboration has decided to open the result to broader scrutiny. The collaboration’s result is available on the preprint server arxiv.org: http://arxiv.org/abs/1109.4897

You Want it WHEN?

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Work begins on Babbage’s Analytical Engine

Work has gotten underway on Plan 28, a project to create Charles Babbage’s Analytical Engine, the never-built successor to the Difference Engine. The Analytical Engine was to have been a general purpose computer, and Ada Lovelace designed the first-ever programming language to run on it. Many factors led to its never being completed — the state of the art in precision engineering in Babbage’s day, finance woes, and so forth.

Popcorn Gun

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Popcorn pops because the water inside flashes to steam and expands. If you put the system under sufficient pressure it won’t do this … until the pressure is released, and all of the popcorn pops at the same time.

Gimme an "A"! No, Really, Gimme an "A"

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Big Ed: School’s Out Forever

People who were doted on in childhood, driven a mile to Cross-Country practice, aren’t going to accept spending four years someplace where they aren’t comfortable and emotionally supported. We began to see a Vice-President of Student Success, a Residential Communications Coordinator, a Coordinator of Learning Immersion Experiences, a Director of Intramural Athletics. And a sushi chef. The next thing you know, it takes two hundred thousand dollars to have a proper college experience. But hey, cheer up. At least you know they’ll graduate with an A average.

You Shall Not Pass!

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Chad addresses the issue of the greenhouse effect in your car, and whether putting a sunshade inside or outside matters: Greenhouse Physics and Car Shades

In the first comment we find the following question

Does car window glass block IR?

to which Chad answers

I like the idea of testing this with a piece of glass and a heater. You could probably do it with a toaster or an electric stove and a Pyrex baking dish (don’t put the dish directly on the burner, though, because they can explode that way)

Here you go. I had a beaker rather than a baking dish, and I used the IR thermometer I demoed a few months ago

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You can see that the filaments are heating up, but when the beaker is put in place, the temperature drops to ambient. So it blocks basically all of the IR in the region of sensitivity of the device.

If You Love Them, Set Them Free

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Free charges in conductors

There’s a great discussion in Griffiths book on electromagnetism (typical book used for junior/senior course for physics majors) about what happens to free charges inside a conductor. He discusses how they will always find their way to the surface, distributing themselves to cancel the field inside the conductor. If they don’t do that, there will be a residual field to push more charges around. This happens until the field is totally cancelled. In a footnote he mentions how this surface effect only happens in 3D. In lower dimensions, like charges on a plate, say, the charges don’t necessarily go to the boundary.

Some neat simulations of both 3-D and 2-D cases.