Physics
esiegel | September 22, 2011"A fact never went into partnership with a miracle. Truth scorns the assistance of wonders. A fact will fit every other fact in the universe, and that is how you can tell whether it is or is not a fact. A lie will not fit anything except another lie."
-Robert Green Ingersoll
One of the most amazing facts to comprehend about the Universe is that it actually is comprehensible! A few basic laws, properties and particles, given our current understanding, can take us from a hot, dense, nearly uniform Universe to the complexity of the billions of stars within the billions of galaxies we see today…
drorzel | September 20, 2011I'm looking at an email from my editor when Emmy wanders by the computer, sniffing around just in case a crumb of food has fallen on the floor in the last five minutes. "Hey," I say, "Come here and look at this."
"Look at what?"
"This:"
"It's the cover for my new book."
"A-hem."
"OK, fine, it's the cover for our new book. Anyway, what do you think?"
"Hey, that's not bad. I'm way better than that dog, though."
"Yeah, well, they didn't want to make the owners of inferior dogs jealous."
"Oooh. Good point. See, this is why I could never make it in marketing."
"It's Madison Avenue's loss, I'm…
esiegel | September 19, 2011"After all, the universe required ten billion years of evolution before life was even possible; the evolution of the stars and the evolving of new chemical elements in the nuclear furnaces of the stars were indispensable prerequisites for the generation of life." -John Polkinghorne
There are close to a whopping 1028 atoms in your body. And while just over half of them are hydrogen atoms, all the rest of them -- from Lithium to Uranium -- were made inside of stars, and ejected back out into the Universe, where, billions of years later, they made you.
Image credit: Ed Uthman.
In fact, a great…
drorzel | September 19, 2011I got a new comment on an old post asking an interesting question about thermodynamics:
I have a question that bears somewhat on this issue of keeping cars parked in the sun, cooler. You all know those accordion folded/aluminized shades you can put up inside the windshield and back window.
Seems to me putting them INSIDE is the wrong approach. They should be on the OUTside of the window acting as real shades and reflecting away the sun before it gets into the inside of the car.
This involves some of the same physics involved in the ever-popular issue of climate change, so it's worth talking…
drorzel | September 18, 2011As mentioned a while back, I'm experimenting with "active learning" techniques in my intro courses this term. Specifically, I'm doing a variant of the "Peer Instruction" method developed by Eric Mazur and others. There are a few complications imposed by our calendar/ class schedule, but I'm giving it a shot, and I thought I'd report on what I'm doing and how it's going, for the benefit of readers who are interested, and on the off chance that some of my readers who are in education can give some feedback/ tips/ whatever.
What I'm doing: The Peer Instruction method is based on shifting the…
sciencepunk | September 14, 2011In 2007, the smash-hit game BioShock told the story of Rapture, a city built on the Atlantic seabed dedicated to the pursuit of the free market. Now academic Alexander Wissner-Gross has revealed how the race for light-speed trading could fuel the development of something remarkably similar.
High frequency trading (HFT) exploits tiny differences in the price of a commodity across two markets. As these discrepancies can last a fraction of a second, trading is carried out by computers that make thousands of transactions in milli- or even microseconds. At these speeds, the time it takes to…
esiegel | September 12, 2011"Nothing in the universe can travel at the speed of light, they say, forgetful of the shadow's speed." -Howard Nemerov
I know many of you are still mad at the night sky because of the full Moon preventing you from seeing the recent, close-by supernova in the Pinwheel Galaxy, at least until the end of the week.
Image credit: Original source unknown, retrieved from the Rose City Astronomers.
With the full Moon brightly illuminating your sky (and filling it with light pollution), only the brightest, most compact objects are visible at most locations on Earth.
But there is one object -- rising…
drorzel | September 12, 2011In typical fashion, no sooner do I declare a quasi-hiatus than somebody writes an article that I want to say something about. For weeks, coming up with blog posts was like pulling teeth, but now I'm not trying to do it, it's easy...
anyway, that's why there's the "quasi-" in "quasi-hiatus," and having been reasonably productive in the early bit of the weekend, I have a few moments to comment on this column by Ben Goldacre about bad statistics in neuroscience. It seems lots of researchers are not properly assessing the significance of their results when reporting differences between measured…
drorzel | September 8, 20111 And the LORD looked upon the earth, and, behold, it was corrupt; for all flesh had corrupted his way upon the earth.
2 And the LORD said unto Noah, The end of all flesh is come before me; for the earth is filled with violence through them; and, behold, I will destroy them with the earth.
3 Make thee an ark, and this is the fashion which thou shalt make it of: The length of the ark shall be three hundred qubits, the breadth of it fifty qubits, and the height of it thirty qubits.
4 And Noah asked the LORD, What is a qubit?
5 And the LORD replied unto Noah, A qubit is a two-level quantum…
drorzel | September 6, 2011It's been a while since I did any ResearchBlogging, first because I was trying to get some papers of my own written, and then because I was frantically preparing for my classes this term (which start Wednesday). I've piled up a number of articles worth writing up in that time, including two papers from an early-August issue of Nature, on advances in experimental quantum computation (the first is available as a free pdf because it was done at NIST, and thus is not copyrightable). These were also written up in Physics World, but they're worth digging into in more detail, in the usual Q&A…
drorzel | September 1, 2011While I was out in Denver, Joss Ives had a nice post asking what courses are essential in a physics degree?. This is an eternal topic of discussion in undergraduate education circles, and I don't really have a definitive answer. It's an excellent topic for a poll, though, so here you go:
Which of the following courses are essential for an undergraduate degree in physics?
"Essential" here means "it would be kind of ridiculous to award a physics degree to a student who hadn't had this class." A class that is nice to have, but could be picked up in graduate school if necessary does not count as…
drorzel | September 1, 2011As previously noted, I'm planning to do more active-learning stuff in my intro mechanics courses this fall (starting next Tuesday), and as a result have been reading/ watching a lot of material on this (which, by the way, includes far too many slickly produced sales videos and not nearly enough "here's an example video of a full class using this technique"). This is doing little to make me less apprehensive-- most of these assume both a leisurely semester calendar and TA-led recitation sections for teaching problem-solving-- but I still like the idea, and want to give it a go.
One of the…
esiegel | August 31, 2011"I trust in nature for the stable laws of beauty and utility. Spring shall plant and autumn garner to the end of time." -Robert Browning
Like everything else that we know of in the Universe -- galaxies, stars, and planets -- human beings are made out of atoms.
Image credit: J. Roche at Ohio University.
And just like galaxies, stars and planets, over 99.9% of the mass of your body isn't just made up of atoms, it's made out of the nuclei of those atoms.
And if you go inside these atoms, into the heart of them, you'll find that these nuclei are combinations of two simple nucleons: the proton…
esiegel | August 30, 2011"My girl, my girl, don't you lie to me,
tell me where did you sleep last night?
In the pines, in the pines, where the Sun don't ever shine,
I'll shiver the whole night through." -Leadbelly, among many other variations
It's already been a couple of months since I wrote about Global Warming, and was deluged with comments that (to be kind) objected to the scientific consensus that the Earth is getting warmer, and humans are very likely the cause.
So let's just take a look at the basic physics of how a warm object -- like a planet -- stays as warm as it does in a cold environment, like…
esiegel | August 26, 2011"A cloud is made of billows upon billows upon billows that look like clouds. As you come closer to a cloud you don't get something smooth, but irregularities at a smaller scale." -Benoit Mandelbrot
It isn't just the clouds that appear smooth, but aren't if you zoom in close. In fact, it isn't just the mathematical curiosity known as the Mandelbrot set that's full of irregularities and ever increasing complexity as you zoom in.
It turns out that the entire Universe itself has these properties.
"Excuse me," you might say. "My Universe is certainly not smooth."
And of course, you'd be right.…
drorzel | August 26, 2011The week before last, I finished writing up a pedagogical paper I've been meaning to write for some time, and sent it off to The Physics Teacher. A couple of days ago, it occurred to me that I could probably post that to the arxiv. So I did, just before I left town for an extended weekend reliving my college days:
Investigating Systematic Uncertainty and Experimental Design with Projectile Launchers
The proper choice of a measurement technique that minimizes systematic and random uncertainty is an essential part of experimental physics. These issues are difficult to teach in the introductory…
drorzel | August 22, 2011A few people last week were linking to this press release from Fermilab, which probably says more about the state of American particle physics than anything else: it's about an experiment that they expect to be approved in 2012, to break ground in 2013, and start running in 2016. I guess with the Tevatron shutting down and nothing noteworthy from the LHC yet, this is what you have to talk about.
The experiment in question is an update of an experiment from Brookhaven in 2001, which measured the anomalous magnetic moment of the muon. The value they get differs from the best theoretical value…
drorzel | August 21, 2011A physics story makes the front page of the New York Times today. Sadly, it's with the headline Laser Advances in Nuclear Fuel Stir Terror Fear. Sigh.
The key technological development, here, is that General Electric has been playing around with a laser-based isotope separation technique. This is an idea that's been around for a long time, with lots of different people working on it. GE's technology is based on an idea from some Australians back in the 1990's, and they appear to think they can scale it up to industrial scale. Predictably enough, there's a stark difference of opinion about the…
esiegel | August 20, 2011"An appeaser is one who feeds a crocodile, hoping it will eat him last."
-Winston Churchill
Ever wonder what will happen to the Earth once the Sun dies? Although it's happening very slowly, the Sun is burning through the nuclear fuel that powers it, giving off a tremendous amount of energy all the time as it happens.
Image credit: NASA's STEREO A spacecraft.
Like all stars, the Sun burns progressively hotter as it ages. A few billion years ago, solar output was 10% less than it is today, and a few billion years from now, it will burn so hot that our oceans will boil, something that only…
drorzel | August 19, 2011Back in June, when I was headed to DAMOP, I got email telling me that they had an official Android app. I installed it, and in with the meeting program and maps and things was a "Social Media" section, that included an official hashtag: #apsdamop.
I posted a few things using it, but it rapidly became clear that there was only one other person at the meeting using it. I happen to know him, so when I ran into him later at the poster session, I commented on how we were the only people at the meeting using the official Twitter hashtag. Someone else nearby looked baffled, and we had to explain.…