Category Archives: Physics

PZ in the Crosshairs

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Over at Pharyngula, PZ Myers is complaining that all the cartoonists are making fun of him

It’s true.

Before I even knew he existed, I drew a cartoon depicting cephalopod torture. It was a promotion for a talk on superconducting quantum interference devices, or SQUIDs. (I got criticism that it’s more an octopus-looking thing in the vat, rather than a squid. They’re physicists. They don’t know any better.)

squidsmall.jpg

In the thank-you note for I got for this, the author encouraged me to do more cartoons on physics topics, since (he claimed) physicists generally don’t recognize themselves in cartoons.

Solar Sails and Squirrels

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Over at the XKCD blag, Randall discusses solar sails and levitating squirrels. And he’s absolutely right — the Back-to-the-Futuresque 1.21 Gigawatts will levitate about a kg, assuming perfect reflection. Assuming absorption, you vaporize the squirrel in a couple of milliseconds.

(1 kg of water requires about 2.5 million Joules to boil away, starting at body temperature. Or not — the latent heat of vaporization is the dominant term)

I think the XKCD cartoons are often quite funny, BTW. A link, if by some odd chance you were unaware of them. I just got a new light box to replace my broken one. Must find time to draw cartoons.

I Am Static Man

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I’m shocked, shocked, to find that I’m getting shocked. My adventures with static electricity.

It’s winter, it’s dry and that makes for pretty good sparks. I haven’t been going to the gym the last few mornings (recovering from being unwell) but have been going to work, so that means peeling off some layers of cotton clothing in the dark. And that means some static electricity. I must roll around a lot in my sleep or something, because there are a lot of sparks a-flyin’ when I take my socks off, and also my sweatshirt. I used to have a blanket (when i was about 10) that would spark nicely if I covered myself and did a bicycle motion while on my back, so my stocking feet continually rubbed on the blanket; since I was covered it was dark, and there were lots of sparks. Slippers on the carpet were always good for sister-annoyance, too, back then. Or just scuffling along holding a fluorescent bulb and watching it flash occasionally, if you could find a dark room.

At the lab, I’m the one who usually peels off the sticky mats in the lab area. (I must have the lowest threshold of being bothered by them being dirty, partially conditioned by being the one who had to clean the optics before we transitioned to semi-sealed modular systems with lots of connecting fiber). Big, big zaps with those. You can get a similar result if you ever buy plexiglass that’s encased in plastic wrap. I bought some big ones (72″ x 40″ to cover some hallway posters near my office), and there were some packing peanut scraps nearby. Once you charge those puppies up, there are some styrofoam pieces that have a huge charge/mass ratio, and simply will not leave your hands until you’ve thoroughly discharged yourself. I had one that was just on the threshold, so when I flicked it off my hand, it would separate a little bit, but not far enough for the gravitational force to be larger than the attractive electrostatic force, so it would float back. Minutes of geeky fun.

For Christmas I got a shirt that’s made of teflon. Partially, at least. The instructions say not to use a dryer sheet with it and this shirt tumbling in the hot dryness really generates the static. And boy does it cling. The first time in the dryer it picked up some serious lint, and I had trouble picking it off because of the amount of charge — I pulled a small piece of string off of it, and when I tried to drop it in the trash can, letting it go about a foot away from the shirt, it flew back to the shirt. More minutes of geeky fun with that. I hesitate to admit that recently when I was ironing and generating some static charge, I empirically reminded myself that the ironing-board pad does not cover the edge of the ironing board, which is just below waist-level. I experienced a dramatic lowering of the potential difference between the ironing board and me, via the part of me closest to the exposed metal. (If you can’t paint a mental image of this, tough. I won’t draw you a diagram).

Lycanthropus Interruptus

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Lunar eclipse tonight

The entire event is visible from South America and most of North America (on Feb. 20) as well as Western Europe, Africa, and western Asia (on Feb. 21)

Unless your weather sucks, of course.

Snow showers in the morning will give way to a mixture of rain and snow for the afternoon. High near 40F. Winds SW at 5 to 10 mph. Chance of precip 60%. A slushy accumulation of less than one inch.

Mmmmm. Slushy accumulation…

The Comfy Chair, er, MOT

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Over at Uncertain principles, Chad talks about how Nobody Expects Bose-Einstein Condensation, i.e. while the phenomenon had been predicted, the enabling technology was serendipitous.

What really made [magneto-optic trapping] take off, though, was that people figured out you could get the laser cooling wavelength for rubidium from diode lasers. And diode lasers are manufactured in mass quantities because they’re used in CD players, laser printers, and other commercial electronic devices. So, rather than needing to spend a couple hundred thousand dollars to get a dye laser system up and running, you could get a working laser system for a couple of grand.

And it’s true. The main enabler was the availability of diode lasers. And their ability to be tuned electronically and thermally. Ah, two! The the two main enablers were their availability and their ability to be tuned, and their susceptibility to optical feedback. Oh, three! The three main enablers were their availability and their ability to be tuned and their susceptibility to optical feedback. Hmmm. Among their advantages are such diverse elements as their availability and their ability to be tuned and their susceptibility to optical feedback, and a nice red color. Damn.

The main enabler was their availability. Blah, blah,blah.

OK, I’m kidding a little, because without the technical advantages, who cares if it’s available? But it’s an excuse to do a Python bit, and talk about the other things.

Laser diodes are pretty neat, though somewhat fragile. In the days of building my own systems, I never knew one that died a natural death-from-old-age. They all got blown up somehow, and I wish that had been in the days of digital cameras, because I recall one that looked cool under the microscope, with one facet blown off but still the piece still hanging there, attached to a tiny wire that was part of the circuit. You had to remove the can that surrounded the diode before you could mount them in our homemade system, and that took some practice. But there were usually some dead or otherwise useless diodes around for practice for newcomers to the lab.
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Nanofear

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Nanotechnology isn’t morally acceptable to a lot of people.

My immediate reaction, after playing “what the?” is that this is a reaction from ignorance. I mentioned before that many people get visions of nanobots taking over the world dancing in their heads when you mention the word “nanotechnology” so I suspect this is just a simple reaction. It’s unknown, so I am suspicious and am predisposed to rejecting the idea. Calling it immoral is just an easy way to reject it, requiring little thought.

Of course it’s ignorant, because most of the respondents probably have a computer, which has nanoscale components in it. And use other nanotech products, perhaps even on a daily basis.

I’m not sure how the pollster draws the religious conclusions, because the poll questions aren’t given and we only have his word that the people were well-informed adults. I don’t trust polls, especially ones that are opaque.

Gazing Into the Relative Past

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Came across a great post entitled “The Pre-history of Einstein’s Relativity” over at Skulls in the Stars.

It starts with Galileo and the notions he had to overturn, and progresses through Newton and through to about 1900 1880.

Regarding Newton and relativity,

The first excerpt observes that understandings of space, time and motion that arise from everyday experience lead one to certain ‘prejudices’, or misunderstandings, about the nature of these quantities. In particular, there is a confusion concerning the ideas of ‘absolute’ and ‘relative’ motion. These seem to be the same misconceptions we discussed earlier in the context of Galileo’s work.

Which applies to a whole bunch of physics, especially quantum mechanics, in addition to relativity.

(via Science After Sunclipse)

Added 2-20: next installment, in-depth Newtonian Ralativity

Let Us Hope It Does Not Become Widely Known

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So tachyons enter the conversation at SFN once again, and I was looking over the wikipedia article

And it says, in part, “the same formulae that apply to regular slower-than-light particles (“bradyons”) also apply to tachyons”

Bradyons? That’s a new one on me.

Obviously there are two types, or genders. They show bunching behavior. The first generation has one particle while the second generation has three. One gender has the property of brown hair, while the other is gold. The last one in the second generation in curls. And then there’s the interaction-regulator, or “housekeeper” particle, known as “Alice.” (OK, I recently saw the scene in “Hot Shots” where they are using the Brady Bunch theme as a cadence, so I still had this in the buffer somewhere)

But really, I wanted to know if I was out of the loop or if something was funny here. I know there are plenty of terms in particle physics that aren’t particularly familiar, but tachyons are recognized in a much wider circle. So why hadn’t I heard of bradyons before? (At first I thought it was a typo and bad physics, and the author meant baryon. But that was not it.) When I Googled I got about 4,200 hits for bradyon (and, while I got more than 2,000,000 for tachyon, many of the bradyon hits I saw were discussing the validity of the term or not about physics. Tachyon probably isn’t anyone’s name — though I readily admit to underestimating the “creativity” of some folks in naming their children) but there’s probably a lot of sci-fi hits. A Google scholar search shows 141 hits, spread out in time with some dating back to 1974, but about 8,500 for tachyon.

So I suspect it’s someone who keeps interjecting the term, hoping it will catch on, and the wikipedia pages are just another attempt, trying to draw attention to it.

I suspect Jan.

Unlimited Cake and Ice Cream

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The first law of thermodynamics: Energy can neither be created nor destroyed. Pretty straightforward. No loopholes.

So why does a press release from Los Alamos sound like it’s ignoring the first law of thermodynamics after painting the room green?

Los Alamos National Laboratory has developed a low-risk, transformational concept, called Green Freedom™, for large-scale production of carbon-neutral, sulfur-free fuels and organic chemicals from air and water.

Sounds great, doesn’t it? Carbon-neutral fuel. Wow, just what the doctor ordered.

By integrating this electrochemical process with existing technology, researchers have developed a new, practical approach to producing fuels and organic chemicals that permits continued use of existing industrial and transportation infrastructure. Fuel production is driven by carbon-neutral power.

OK, no actual mention of the electrochemical process in the PR, but elsewhere it’s given as methanol production from water and carbon dioxide.

So it must be the reverse of 2 CH3OH + 3 O2 → 2 CO2 + 4 H2O

Which is going to require energy input, because the combustion of methanol is exothermic. Ah, hence the mention of the fuel production being driven by a carbon-neutral source. Recognize that? It’s the same handwave that was happening with hydrogen a few years back. It’s not an energy source, but at least it’s green … as long as you use a green source of energy.

If we had some cake we could have cake and ice cream. If we had some ice cream.
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If You Have To Teleport Me, Then I Don't Wanna Go…

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Aldebaran’s great, okay,
Algol’s pretty neat,
Betelgeuse’s pretty girls
Will knock you off your feet.
They’ll do anything you like
Real fast and then real slow,
But if you have to take me apart to get me there
Then I don’t want to go.

[Chorus]

Take me apart, take me apart,
What a way to roam
And if you have to take me apart to get me there
I’d rather stay at home.
— Douglas Adams, “The Hitchhiker’s Guide to the Galaxy”

Another recurring theme on the SFN forums is quantum teleportation, along with quantum entanglement. Quantum teleportation is all about sending information, not matter.

Jeff Kimble explains some truths about teleportation