The Backyard Arthropod Project
“A Field Guide to the North Side of Old Mill Hill, Atlantic Mine, MI”
Bugs, not in close proximity to me, so I don’t mind so much. Apparently many of them are attracted to or otherwise like to hang out on graph paper. I had no idea…
Much like Google Maps in that there are areas that are not mapped in great detail, and others where you can zoom all the way in (it shouldn’t be all that hard to guess that this correlates with interesting features in the night sky). No “street view” feature, yet.
My soft drinks are trying to kill me.
Not really an experiment, just an event from a little while back. Soda (or pop, depending on where you live) bottle of the 2L variety, that was sitting on top of the fridge, where it was a few degrees above room temp. I heard a muffled “boom” from the computer room, and found this, along with most of 2L of soda all over the fridge and floor. It’s generally agreed that these bottle can usually withstand upwards of 100 psi, with some empirical data from people using such bottles for water-rocket fun. So I’m pretty sure I either had me a defective bottle, or it was rigged in a botched assassination attempt.
Notes from a recent colloquium:
YORP is the acronym from Yarkovsky, O’Keefe, Radzievskii and Paddack, several of the people that described the effects of radiation on the behavior of small celestial bodies. Kepler actually first broached the idea that light from the sun could affect orbits, and the idea has been fleshed out since then. Yarkovsky proposed that the thermal radiation emission could cause a torque on a non-uniform body, and this was later expanded to include radiation pressure effects — the incoming radiation has an effect as well. Radzievskii’s contribution was the idea that albedo changes or differences could contribute, but since absorption and thermal re-emission doesn’t look much different than scattering, from a momentum standpoint, it turns out to be a small effect.
Paddack gave part of the talk, and described the experimental steps taken to investigate this. He took asymmetric rocks and let the fall in a pool — the still water was a proxy for a uniform radiation pressure once the rock had reached terminal velocity — and observed their motion, measuring the increase in rotation rate and deducing an empirical formula for the effect. Later he was able to construct a small-scale satellite that was hung in a vacuum chamber by a thin filament attached to a magnetic bearing (essentially no friction) and observed the angular acceleration when a bright light was shone on the target.
The effect has been observed, with 2000 PH5 getting a lot of press (well, geek press) about a year ago. The effect is more prevalent in smaller bodies — moment of inertia grows faster than surface area as objects of uniform density get larger. Since asteroids are often not held together strongly, increasing the rotation rate can cause them to eject mass, changing their orbit. And it’s not just spin rate; you can get precession and nutation as well, and there is an interplay with the gravitational torques that give rise to some resonances. It is thought that this explains the existence of some binary asteroids.
Nongravitational effects like this are important to know for manmade satellites, such as GPS, whose orbits need to be precisely determined.
Cryogenic dark matter search (CDMS) signals converted into visual and audio
(OK, who didn’t have one of these in their dorm rooms in college? 🙂 )
There’s a pepsi-through-the-nose funny part, too, (at least according to my calibrations) about halfway through. What a dark sense of humor!
From the Fermilab newsletter, via physics and physicists
One thing about R & D is that the project eventually moves you from physics (the “R” part) over to something that’s more engineering in nature (the “D” part). Here’s a quick example. Here’s the laser system for the caesium fountain, which is a research device. It’s spread out to be optimized for getting your hands in and tweaking on knobs, since you don’t know ahead of time what is going to work best. Lots of mirrors and other optics that need to be adjusted, and there has to be room to change things around and/or add things that might work better. You have to generate six beams for trapping (this is done at the table under the big cylinder, splitting two beams from the main table), plus a beam for optical pumping and another for probing the atoms. That’s four different beams on the table, at various (and for the MOT, adjustable) frequencies. The long paths meant that the beams would only stay aligned into the fiber couplers for, at best, weeks at a time.
Eventually you decide on a design that works, and since our production devices need to fit into a smaller space, and aren’t meant to be adjusted much (ideally, not at all) after the initial setup, you make everything smaller. Pretty much everything except the lasers (the 2 blue boxes on the left and 3 black boxes; one center-front and two right-rear) and the spectroscopy (which ends up on a different table) are compacted to fit on a much smaller table.
Everything is fiber-coupled, so it’s modular — it doesn’t matter which particular laser you use, or what you do with the beams after they leave the box. As you can see, it’s rack-mounted, and about 4u high. (You can just see another table at the top of the picture; this houses the spectroscopy/locking hardware)
Chad’s been busy blogging about his recent lab visits to NIST and U. Maryland, and the writeups are, as usual, top-notch. Cavity QED (a subfield I find fascinating and something I might have pursued had the right opportunities arisen when I was looking for a postdoc), Cold Plasmas, Biophysics (you might have a “what the?” reaction, but it uses optical tweezers, which is why this doesn’t really fall under “one of these things is not like the other,” Four-Wave Mixing (another field I find interesting, and the summary is definitely worth a read if you’ve ever wondered if things you learned in QM were ever actually applied to anything. You’ve got electrons moving between states without ever exciting the atom, and squeezed states, which is an exploitation of the Heisenberg Uncertainty Principle)
Last but not least one on this list (so far, anyway) is about trapping Francium. As I mentioned in the U.P. comments, I was a postdoc in the group that tried to trap Francium at TRIUMF several years back, and when we started discussing plans to do it, we were hoping to trap before the Stony Brook lab did so. Well, they succeeded while we … met some obstacles. As I recall, we weren’t the first in line to use the target; there was another experiment that went first, and so we only had a short time to try. And trying to trap something that has no stable isotopes is a special challenge. You have to reference your laser to something, so that you know he frequency of the light you are generating. With an existing stable isotope that’s straightforward, since you can use an absorption line, and the frequency of the radioactive isotope would be close by. Otherwise you do something like locking to an iodine transition, or some other reference cell used in spectroscopy. And you have to know the frequency you want to generate — with no stable or at least naturally-occurring isotopes the spectroscopy information would be very sparse in comparison to other alkalis, so your calculation of where you expect the transition to be has some uncertainties, meaning you have to search frequency-space until you find something. And we ran out of beam time before we saw anything.
And, as I had mentioned, we (well, someone at TRIUMF) got a call from a watchdog station that tries to detect nuclear fallout, wanting to double-check on things. They knew the signature they were reading wasn’t from a bomb, but they knew something was up and guessed our target material: Thorium. When you blast that with energetic protons, you get lots of heavy isotopes.
Today’s the day! I’m all over this one. Talk like a physicist
If anyone needs some pointers:
Use “canonical” when you mean “usual” or “standard.” As in, “the canonical example of talking like a physicist is to use the word ‘canonical.'”
Use “orthogonal” to refer to things that are mutually-exclusive or can’t coincide. “We keep playing phone tag — I think our schedules must be orthogonal”
“About” becomes “to a first-order approximation”
Things are not difficult, they are “non-trivial”
Large discrepancies are “orders of magnitude apart”
Refer to coordinates and coordinate systems. “I got shafted” becomes “I took one up the z-axis”
Any actual personal experience becomes “empirical data.” i.e. a burn on your hand is empirical data that the stove is hot.
You’re not being lazy, you are in your ground state.
A semi-educated guess is an extrapolation
You aren’t ignoring details, you are taking the ideal case
A tiny amount is “vanishingly small” or “negligible.” Really small is “infinitesimal”
You aren’t overweight, you are thermodynamically efficient
Stuck in a meeting is “trapped in a potential well,” though you hope you can “tunnel out.” Alternatively, it can be a black hole, from which there is no escape.
it’s not a wire, it’s a “conductor”
It’s not light, they are photons. Turning on the lamp becomes emitting photons.
This is the kind of spontaneous publicity, your name in print, that makes people. I’m in print! Things are going to start happening to me now! Navin R. Johnson
I’ve actually been in print before, with some cartoons published in Physics Today back when they had an art editor with taste who liked my work. Since then, not so much.
A little over a year ago, a book editor asked for permission to use a cartoon and I agreed, shrewdly negotiating a free copy as my payment. The book was originally scheduled to be published this past summer, but that slipped a bit and confirming publication fell off my radar. It looks like it was published in November, and I went a-lookin’ for it this week, because I haven’t gotten my copy yet! (and email to the editor keeps bouncing)
The first big-chain bookstore I visited (the one that starts with a “B”) didn’t have it, but if they did, it would have been in “Young Adult Non-Fiction,” which is a section that didn’t appear to exist in their store. Plenty of Young-Adult Fiction, with many warnings about how the content may not be appropriate for some readers, and I’m sure that would be an effective lure if any young adults read anymore. The second big-chain bookstore (that other one, that starts with a “B“) had it on one of their display tables that was still being stocked with a whole bunch of science-y books. (Overheard: “Mumble mumble Women’s brain. OK, Woman’s brain over here. Men’s brain? Is there a men’s brain? No men’s brain? OK.)
Anyway, the book in question is “The Story of Science: Einstein Adds A New Dimension” by Joy Hakim, published by Smithsonian Books. My cartoon appears on p. 162
From my quick glance through it, it looks great, and I’ve read good things about the first two books in the series. (I also noticed at few Sidney Harris cartoons in it. I wonder what kind of deal he got?)
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My other exposure news (that involve neither a trench coat nor shrieking) was some sweet, sweet linkage from Uncertain Principles that pushed my Technorati authority into double-digits and my ranking to the sunny side of the Mega mark. I’m slightly more relevant than before! Woohoo!