Physics
esiegel | July 12, 2011"Sometimes I don't want to see the puppeteers,
sometimes I just want to see the magic therein,
and sometimes I just want to pry open the atoms
and know why they spin." -Glen Sutton
But it isn't just the atoms -- the minuscule building blocks of matter -- that spin. It's also the individual galaxies, collections of some mind-boggling number (like 1068) of atoms, that spin.
Image credit: Jean-Charles Cuillandre, Giovanni Anselmi and the CFHT.
Messier 95, above, is just one such example. But how did these galaxies get to be this way?
To answer this question, we have to go all the way back to…
drorzel | July 12, 2011Among the articles highlighted in this week's Physics is one about a new test of QED through a measurement of the g-factor of the electron in silicon ions. This comes on the heels of a measurement of proton spin flips (this includes a free PDF) a couple of weeks ago, and those, in turn, build on measurements of electrons from a few years back, which Jerry Gabrielse talked about at DAMOP. Evidently, it's magnetic moment season in the world of physics.
The media reports on the proton experiment tend to be a little garbled in a way that reveals the writers don't quite understand what's going on…
drorzel | July 12, 2011A month and a half ago, I reported on a simple experiment to measure the performance of a timer from the teaching labs. I started the timer running at a particualr time, and over the next couple of weeks checked in regularly with the Official US Time display at the NIST website, recording the delay between the timer reading and the NIST clock.
As a follow-up experiment, I did the same thing with a different timer, this one a Good Cook brand digital timer picked up for $10 in the local supermarket, and the same Fisher Scientific stopwatch/timer as the first experiment, with the Fisher…
drorzel | July 11, 2011(Note: This was not prompted by any particular comment. Just a slow accumulation of stuff, that turned into a blog post on this morning's dog walk.)
It's been a couple of years now that I've been working on writing and promoting How to Teach Physics to Your Dog, so I've had a lot of conversations where the subject of writing a popular audience book on quantum physics comes up. I've had enough of these now that I can recognize a few different categories of responses, one of which drives me up the wall. I suspect that the same is true for most pop-science authors, so as a public service, let me…
drorzel | July 11, 2011We took SteelyKid to the playground at one of the local elementary schools on Sunday morning. this one includes an odd sort of slide, made of dozens of rollers that are 1-2 inches in diameter (they're all the same size-- the range is just because I didn't measure them carefully). They're on really good bearings, and while it's kind of noisy, it's a reasonably smooth ride.
There is, however, one slightly mysterious aspect to this slide, clearly visible in this video that Kate was good enough to shoot for me:
SteelyKid takes something like 6 seconds to go down the slide, while it only takes me…
drorzel | July 8, 2011The final content area from my DAMOP overview is Precision Measurement. This is also the smallest area, with only one invited session on the topic on Fundamental Symmetry Tests, though two of the "Hot Topics" talks (by Zheng-Tian Lu and Ed Hinds) were precision measurement talks. You might be able to make an argument that this doesn't really deserve its own category, but I was the one giving the talk, and I love this stuff (though I absolutely do not have the temperament necessary to do it), so it gets its own category.
I also think there is a fairly distinct culture to precision measurement…
esiegel | July 6, 2011Poets say science takes away from the beauty of the stars -- mere globs of gas atoms. I, too, can see the stars on a desert night, and feel them. But do I see less or more? -Richard Feynman
Ahh, the stars that make up our galaxy, and the galaxies that make up our Universe. It's the simple power of the humble atom -- the protons, neutrons, and electrons that are the building blocks of everything on our world -- that powers all the stars and galaxies in the Universe.
Image credit: Antoine Vergara Astrophotography.
But it didn't need to be this way! Why is it that all the stars in our galaxy,…
drorzel | July 6, 2011Today's Links Dump came late because I was at the meeting of the APS's Committee on Informing the Public. We apologize for the inconvenience, but I was too busy acquiring this critically important scientific data:
What is that, you ask? It's this:
That's the Superman roller coaster at the Six Flags America park outside of DC, which is where we're meeting this time. Lots of amusement parks do Physics Days as outreach programs, so we did the Physics Day thing ourselves, wearing ugly blue vests holding accelerometers on the major rides. Of course, the vest-mounted accelerometer I was wearing…
drorzel | July 5, 2011The fourth content area from my whirlwind overview of DAMOP is "traditional" AMO physics. This was the hardest to talk about in my talk, because I know it the least well, but ironically, that makes it really easy to write up here, because I don't have much to say about it.
Where the other areas were largely about using atomic, molecular, and optical physics to do stuff (simulating condensed matter systems, generating coherent x-rays, demonstrating cool quantum effects), this sub-sub-field is concerned with directly investigating the properties of atoms and molecules, usually by bouncing other…
drorzel | July 5, 2011I'm going to be at an amusement park tomorrow, for a meeting of the APS's Committee on Informing the Public, which oversees the APS outreach program. Why an amusement park? Because a common outreach-type program is to do a Physics Day at an amusement park and talk about the physics of roller coasters and the like. And why should we miss out on all that fun? we have a responsibility to make sure that the physics content of these programs is sound.
As part of this, I'll be going on a bunch of rides-- for SCIENCE, mind you-- and it occurs to me that while the park or the APS may supply some sort…
esiegel | July 3, 2011"Celebrate the independence of your nation by blowing up a small part of it." -The Simpsons
For those of you who aren't from the U.S. or U.K., this coming Monday is the day that my nation celebrates the birth of its independence. This date, of course, as Aimee Mann will sing to you, is the
4th Of July.And the most common way to celebrate our Independence Day? Fireworks.
How do they work? That sounds like a question for science! (Inspired by Janet Stemwedel's article from 2007, as well as a recent article over at Scientific American.)
You start with three simple ingredients: sulfur, charcoal…
esiegel | July 1, 2011"We are all agreed that your theory is crazy. The question which divides us is whether it is crazy enough to have a chance of being correct. My own feeling is that it is not crazy enough." -Niels Bohr
You know who Einstein is, I'm sure. The E=mc2 guy, the speed of light guy, and -- perhaps most prestigiously -- as the inventor of the best theory of gravity that we have: general relativity.
One of the notable things about gravity -- which is also true of all of Einstein's theories -- is that it's completely deterministic.
What does that word mean, deterministic, to a physicist?
It means that…
drorzel | July 1, 2011Third of the five research categories within DAMOP that I talked about is Quantum Phenomena. This is a little bit of a catch-all, as there are a few different things going on in this area. They are all unified, though, by the fact that they end up making quantum mechanical effects manifest in some way, either as a means to an end, or just for the sake of showing that quantum mechanics is really weird.
What do I mean "making quantum mechanical effects manifest?" Basically, demonstrating one of the essential elements that I talked about last year: showing the wave nature of matter,…
drorzel | June 30, 2011The second in the DAMOP research categories I talked about is "Extreme Lasers," a name I was somewhat hesitant to use, as every time I see "Extreme [noun]," I get a flash of Stephen Colbert doing air guitar. It is, however, the appropriate term, because these laser systems push the limits of what's possible both in terms of the pulse duration (attosecond pulses are common, with 1as = 0.000000000000000001 s) and the pulse intensity (1014 W/cm2 is a typical order-of-magnitude, and some systems get much higher than that).
One of the main tricks for generating these ultra-short pulses is to do…
esiegel | June 29, 2011"Electricity can be dangerous. My nephew tried to stick a penny into a plug. Whoever said a penny doesn't go far didn't see him shoot across that floor. I told him he was grounded." -Tim Allen
I know what you're thinking. "Of course I know what static electricity is!" Oh, really? Let's go through the basics.
You've all (hopefully) gotten to play with a Van de Graaff Generator at some point. It's one of the simplest electricity demonstrations there is. You stand on something like a milk crate, touch your hands to the generator, have someone turn it on, and your hair (for those of you with…
krandall | June 29, 2011By Dr. Friedemann Freund; Carl Sagan Center for the Study of Life in the Universe, SETI Institute, and Gail Jacobs
Friedemann Freund doesn't shrink from taking on the really big problems. His research has elucidated such important phenomena as the fact that rocks under stress behave like batteries that can produce currents deep within the crust of the Earth. These are not piddling electron flows, either - the currents could be as large as millions of amperes, sufficient to be measured above ground, and perhaps even from orbit. Understanding and exploiting this phenomenon could lead to a…
drorzel | June 29, 2011The first of the five categories of active research at DAMOP that I described in yesterday's post is "Ultracold Matter." The starting point for this category of research is laser cooling to get a gas of atoms down to microkelvin temperatures (that is, a few millionths of a degree above absolute zero. Evaporative cooling can then be used to bring the atoms down to nanokelvin temperatures, reaching the regime of "quantum degeneracy." This is, very roughly speaking, the point where the quantum wavelength of the atoms becomes comparable to the spacing between atoms in the gas, at which point the…
drorzel | June 28, 2011That's the title of my slightly insane talk at the DAMOP (Division of Atomic, Molecular, and Optical Physics of the American Physical Society) conference a couple of weeks ago, summarizing current topics of interest in Atomic, Molecular, and Optical Physics. I'll re-embed the slides at the end of this post, for anyone who missed my earlier discussion.
I put a ton of work into that talk, and had a huge amount of material that I didn't have time to include. I'd hate for that to go to waste, so I'm going to repurpose it for blog content over the next week or so. It'll probably be about a half-…
esiegel | June 27, 2011"Doubt, indulged and cherished, is in danger of becoming denial; but if honest, and bent on thorough investigation, it may soon lead to full establishment of the truth." -Ambrose Bierce
About a week and a half ago, I wrote an article called The Power of Theory In Science, where I mentioned the Big Bang, Evolution, and Global Warming as some of the leading scientific theories describing a variety of natural phenomena.
Image credit: Rhys Taylor, Cardiff University.
And while no one took issue with my assertion that the Big Bang and Evolution were the best scientific theories describing (…
drorzel | June 25, 2011"Hey, Dude, what'cha doin'?"
"I'm checking out the dog drawings I commissioned for the book-in-progress. Here, take a look:"
"Hey, wait just one minute. That looks like me!"
"That's the idea. Since you're in the book, I thought it would be nice to have some pictures that look like you, rather than just a clip-art German Shepherd from Office."
"I look kind of worried, dude."
"Yeah, well, you get that look a lot when we're talking about physics."
"Good point. So, was there a point to this, other than showing off the spiffy drawings an art student did for you?"
"Sure. It's a reminder that I'm…