Physics
esiegel | July 31, 2014“The atoms come into my brain, dance a dance, and then go out — there are always new atoms, but always doing the same dance, remembering what the dance was yesterday.” -Richard Feynman
It took 13.8 billion years of cosmic evolution, billions of years of biological evolution and astronomical numbers of events unfolding exactly as they have to give rise to you and me. And yet, here we are, collections of tens of trillions of cells and some 10^28 atoms.
Image credit: Ed Uthman.
Yet even though we don't often think of it, each one of those atoms has its own, unique cosmic story. It's too great…
esiegel | July 31, 2014“By allowing the positive ions to pass through an electric field and thus giving them a certain velocity, it is possible to distinguish them from the neutral, stationary atoms.” -Johannes Stark
One of the simplest tenets of electromagnetism -- the second of the fundamental forces ever discovered -- is that charged particles are accelerated parallel to electric fields, and are deflected as they move perpendicular through magnetic fields. In spectacular fashion, our Earth shows this latter phenomenon off as its bombarded by charged particles from the Sun.
Image credit: NOAA Space Weather…
drorzel | July 28, 2014Given the recent Feynman explosion (timeline of events), some people may be casting about looking for an alternative source of colorful-character anecdotes in physics. Fortunately, the search doesn't need to go all that far-- if you flip back a couple of pages in the imaginary alphabetical listing of physicists, you'll find a guy who fits the bill very well: Enrico Fermi.
Fermi's contributions to physics are arguably as significant as Feynman's. He was the first to work out the statistical mechanics of particles obeying the Pauli exclusion principle, now called "fermions" in his honor (Paul…
drorzel | July 25, 2014I should really know better than to click any tweeted link with a huff.to shortened URL, but for some reason, I actually followed one to an article with the limited-reach clickbait title Curious About Quantum Physics? Read These 10 Articles!. Which is only part one, because Huffington Post, so it's actually five articles.
Three of the five articles are Einstein papers from 1905, which is sort of the equivalent of making a Ten Essential Rock Albums list that includes Revolver, Abbey Road, and the White Album. One of the goals of a well-done list of "essential" whatever is to give a sense of…
esiegel | July 24, 2014“Concentrate all your thoughts upon the work at hand. The sun’s rays do not burn until brought to a focus.” -Alexander Graham Bell
The Sun, contrary to what you might normally think about it, isn't a constant, uniform source of radiation. It has an active surface, replete with temperature variations, sunspots, and occasionally a large flare or mass ejection.
Image credit: NASA / GSFC / SDO.
But on very rare occasion, a flare like this makes it way through space and just happens to make its way towards Earth, where this hot, fast-moving ionized plasma collides with us. While the aurorae it…
drorzel | July 24, 2014This Alberto Cairo piece on "data journalism" has been kicking around for a while, and it's taken me a while to pin down what bugs me about it. I think my problem with it ultimately has to do with the first two section headers in which he identifies problems with FiveThirtyEight and Vox:
1. Data and explanatory journalism cannot be done on the cheap.
2. Data and explanatory journalism cannot be produced in a rush.
The implication here is that "data and explanatory journalism" is necessarily a weighty and complicated thing, something extremely Serious to be approached only with great care.…
esiegel | July 22, 2014“Art has a double face, of expression and illusion, just like science has a double face: the reality of error and the phantom of truth.” -Publilius Syrus
Out in the depths of space, objects range from the incredibly small and low mass to the huge and super-heavy, shrinking down again for the most ultra-massive objects in the Universe.
Image credit: The Antiope Doublet asteroid / ESO, via http://www.eso.org/public/images/eso0718b/.
But what would happen, on all scales, if you took two such identical objects and merged them together?
Image credit: NASA.
Find out what happens when the…
drorzel | July 22, 2014In which our hangout turns nineteen; we may need to look into a special guest for the 20th, or something. Or maybe save guest stars for the one after that, when it can drink.
Anyway, Rhett and I chat about grading, lab reports, why Excel sucks, and an online experiment that we really ought to do if we only had the time.
Some links:
-- Why Does Excel Suck So Much?, and "Line Plot" is Never the Right Choice. Perennial favorites on the blog.
-- How Do I Kill the Squirrels Who Are Eating My Car?, another constant source of a small amount of traffic.
-- Rhett's elevator video post.
-- My soccer…
drorzel | July 18, 2014As noted last week, I went to SteelyKid's day camp on Tuesday to talk about being a college professor. This was a little awkward, because I was scheduled to talk to kids ranging from not-quite-three to six-and-a-bit, and really, what do they care about the daily routine of physics faculty?
So, I did a simple demo. While I got a lot of really interesting suggestions in the comments to last week's post, most of them required more props than I wanted to drag with me. And for that age, simple is often enough. So, I just did the tennis-ball-on-a-soccer-ball trick. For the benefit of readers who…
drorzel | July 16, 2014The surest sign that I've become a Real Author is that there are five months yet before Eureka comes out, and I'm already fretting about negative reviews. Negative reviews that haven't happened yet, but that I know will come, in a particular form.
The book, as you probably know from my prior ramblings on this subject, contains a large-ish number of historical anecdotes illustrating particular aspects of the scientific process, and relating them to everyday activities (rough list in this post). The thing that I worry about is that I decided early on to make a conscious effort to keep the whole…
drorzel | July 11, 2014We got an email from the people running SteelyKid's summer camp asking for volunteers to speak at a career day sort of event early next week. I said "Sure, I can do that, and talk about the glamorous life of a physics professor and book author." They said "Great, you'll be talking to several groups, ranging from second-graders down to 3-4 year olds."
That's... not quite the audience I was expecting (the camp runs up through 5th grade or so). I don't think they're going to care all that much about physics research, so instead, I'll probably say "My job is to teach people about science" and…
catdynamics | July 10, 2014A research group at Lawrence Livermore National Laboratory has produced ultrastiff ultralowdensity metamaterials by 3D printing of microarchitected microlattices.
This is very cool - they do additive 3D printing using microstereolithography with nanocoating and postprocessing and can make self-similar lattices with densities varying by several orders of magnitude in bulk density but near constant stiffness.
Construction material can be metal, ceramic or polymer.
LLNL engineered microlattices from Zheng et al Science 344 1373
The lattice geometry can be controlled to choose what mechanical…
esiegel | July 9, 2014“Trust yourself. Create the kind of self that you will be happy to live with all your life. Make the most of yourself by fanning the tiny, inner sparks of possibility into flames of achievement.” -Golda Meir
If you've never seen the glorious, athletic spectacle that is Sasuke (Ninja Warrior), you are missing out on the obstacle course of a lifetime!
Image credit: © 2013 Etan Ginsberg, via his fan site at http://www.ninjawarrior.info/.
My favorite challenging stage 1 obstacle has got to be the warped wall, famous for wiping out even big, strong and seasoned competitors. But there's a trick…
drorzel | July 9, 2014Text of the ad we're running for our searches this fall. This will go live on the usual sites at the start of August, but as a sort of experiment in the power of social media, I'm going to share it here first, and see what that gets us.
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We invite applications for two tenure-track Assistant Professor positions starting in September 2015, one in any area of theoretical physics or astrophysics, the other with a strong preference for biophysics or soft condensed matter (either experimental or theoretical). We encourage applications from interdisciplinary scientists and those who could make…
esiegel | July 8, 2014“When you’re finally up at the moon looking back on earth, all those differences and nationalistic traits are pretty well going to blend, and you’re going to get a concept that maybe this really is one world and why the hell can’t we learn to live together like decent people.” -Frank Borman, Apollo 8
You've got to wonder about the Moon. I'm not talking about what it looks like or what it has to teach us about Earth, but why the far side of the Moon looks so different from the side that faces us?
Image credit: NASA / JPL - Caltech / LRO.
For the past 55 years, we've known that the far side…
drorzel | July 7, 2014Also coming to my attention during the weekend blog shutdown was this Princeton Alumni Weekly piece on the rhetoric of crisis in the humanities. Like several other authors before him, Gideon Rosen points out that there's little numerical evidence of a real "crisis," and that most of the cries of alarm you hear from academics these days have near-perfect matches in prior generations. The humanities have always been in crisis.
This wouldn't be worth mentioning, but Rosen goes on to offer an attempt at an explanation of why the sense of crisis is so palpable within the humanities, an explanation…
drorzel | July 7, 2014Right around the time I shut things down for the long holiday weekend, the Washington Post ran this Joel Achenbach piece on mistakes in science. Achenbach's article was prompted in part by the ongoing discussion of the significance (or lack thereof) of the BICEP2 results, which included probably the most re-shared pieces of last week in the physics blogosphere, a pair of interviews with a BICEP2 researcher and a prominent skeptic. This, in turn, led to a lot of very predictable criticism of the BICEP2 team for over-hyping their results, and a bunch of social-media handwringing about how the…
drorzel | July 3, 2014I didn't plan to do a follow-up to yesterday's post about the optics of sending messages with lasers, but then I starting idly thinking about detection, prompted in part by a bunch of conversations with my summer students about single-photon detectors. which led to scribbling on the back of an envelope, which led to Googling, and suddenly, I have a follow-up post.
So: as we said yesterday, if you want to send messages over a distance of ten light years, a relatively efficient way to do this might be to send them via lasers. This results in the light being spread over a pretty big area, though…
esiegel | July 2, 2014“What we observe is not nature itself, but nature exposed to our method of questioning.” -Werner Heisenberg
You might think there are few sacred quantities when it comes to matter: properties that are so fundamentally inherent that even the weirdness of quantum mechanics can't touch them.
Image credit: Matt Strassler, via http://profmattstrassler.com/articles-and-posts/particle-physics-basics….
But the quantum nature of the Universe will have none of our prejudices, and will simply do what it does whether we like it or not. And that means, puzzlingly enough, that it's physically impossible…
drorzel | July 2, 2014In the comments to yesterday's grumpy post about the Fermi paradox, makeinu raises the idea that advanced aliens would be using more targeted communications than we do:
On the point about electromagnetic communications: even we are now using lasers to target communications with space, because it’s simply more efficient and reliable.
It’s also basically impossible to intercept, since you literally have to interrupt the beam to do so.
This is true, to a point, but when you're talking about interstellar distances, it's not quite true that you have to interrupt the beam to detect communications…