Another in my continuing series trying to explain some condensed matter concepts in comparatively jargon-free language. So far I’ve talked about electron-like quasiparticles, phonons, and plasmons. Now we consider magnons, also known as “spin waves”. A magnon is another collective excitation, like a phonon or a plasmon, that may be described by a wavelength (or equivalently a wavevector) and an accompanying frequency.
Monthly Archives: March 2009
Looking Up at Bob
Mocking What You Don't Understand
A discussion of recent neuron-deficient attacks on science.
The tricky thing about most basic research, though, is that you don’t always know what you’ll get out of it when you release the funds. Such research often opens up new and surprising avenues that themselves then spin off important innovative technologies that no one could have predicted. (In Jindal’s case, he wasn’t even attacking basic research, but rather, research of obvious disaster safety import. Not even my caveats can help him.)
In an ideal world, then, specific scientific appropriations would hardly be above criticism—but you would also have to make a cogent argument for why they’re not the best use of our investments. You wouldn’t just mock that which you don’t understand
A Polynesian Vacation
The Fact of the Matter
George Will Officially Loses His Mind
More piling on Poor George, for his act of confusing political punditry with science and the acceptability within each discipline of just making stuff up to make a point. But within the arguments, Tom brings up another example that hasn’t been horribly contaminated with politicium:
To get a handle on this last point, leap out of politically (not scientifically) charged areas like the study of anthropogenic climate change. Sixteen years after Einstein had worked out the special theory of relativity, which eliminated the concept the ether as the medium within which light waves travelled, word came of an experiment that seemed to have detected an ether “wind” — the effect produced by the motion of the earth through an ether. Einstein responded with perhaps his most quoted aphorism: Raffiniert ist der Herr Gott, aber boshaft ist er nicht – Subtle is the Lord, but malicious He is not!
Einstein was, of course, correct, and the reported experiment was wrong. The moral of the story, in this context, is that while it is true that a single contrary result is enough to demolish established theory — that result had better damn well hold up.
And that’s something that needs to be understood about the process. Support for a theory is a body of evidence, and if a contrary data point comes up, it is investigated to see if there’s really new science there, or if it’s the result of a statistical fluke, an experiment that lacks some rigor, or even fraud. One of the foundations of science is repeatability — scientists try and replicate results, and if nobody can do so, the result is suspect. A hundred years later there are still those who contort themselves to tear down relativity, but all they can point to is a handful of experiments that show questionable results, as compared to a vastly larger pile of experiments that confirm the theory. The beautiful theory can be slain by an ugly fact, but one has to actually confirm that it is indeed a fact that one has uncovered.
Measuring the Speed of Light in Optical Fiber … Using Email
Oh, this is just awesome, from a geeky reference frame: The case of the 500-mile email
“What’s the problem?” I asked.
“We can’t send mail more than 500 miles,” the chairman explained.
I choked on my latte. “Come again?”
“We can’t send mail farther than 500 miles from here,” he repeated. “A
little bit more, actually. Call it 520 miles. But no farther.”
(There’s a factor of two that’s not explained in the story, for round-trip vs. one-way, but still …)
You're a Pillar
Typically seen in polar regions, the vertical columns of light have been appearing along with frigid temperatures at lower latitudes this winter.
Light pillars appear when artificial light or natural light bounces off the facets of flat ice crystals wafting relatively close to the ground.
Against the Grain
[P]olymers in a solution that isn’t at a uniform temperature behaved in an unexpected way, with the longer molecules drifting toward the coldest region and the very shortest ones drifting toward the warmest region.
Reminiscent of the Brazil Nut sorting problem
Square Day
It’s Square Root Day! – March 03, 2009
If you’re tempted to suppress your inner geek, just remember that Square Root Day only happens nine times a century. The last one was Feb. 2, 2004, and the next one won’t be until April 4, 2016.
And it doesn’t matter which calendar convention you use.
Ultrageekily speaking, the last square (root) day was 12/12/144, but I guess we’re suppressing the leading digits here.
An Inordinate Fondness for Beetle … Sex
Horrific beetle sex described at Not Exactly Rocket Science.
The duo studied beetles taken from 13 countries across the tropics, from Brazil to the USA, and from Nigeria to Oman. The genitals of these different populations are very varied and to study them under a microscope, Hotzy and Arnqvist first had to fluff their subjects. They anaesthetised the males with carbon dioxide, and erected their penises with an “artificial inflater” – a microscopic plastic tip connected to a pump. Under a microscope, they measured the length of the longest spines and the size of the entire spine-bearing area.
Probably NSFW if you happen to be employed by Coleopt-R-Us