I Know Where You Live

I Am Here: One Man’s Experiment With the Location-Aware Lifestyle

To test whether I was being paranoid, I ran a little experiment. On a sunny Saturday, I spotted a woman in Golden Gate Park taking a photo with a 3G iPhone. Because iPhones embed geodata into photos that users upload to Flickr or Picasa, iPhone shots can be automatically placed on a map. At home I searched the Flickr map, and score—a shot from today. I clicked through to the user’s photostream and determined it was the woman I had seen earlier. After adjusting the settings so that only her shots appeared on the map, I saw a cluster of images in one location. Clicking on them revealed photos of an apartment interior—a bedroom, a kitchen, a filthy living room. Now I know where she lives.

Message from the APS

I am writing to request that you IMMEDIATELY contact your elected
representatives and let them know that the proposed Congressional
economic stimulus package must include a strong investment in
scientific infrastructure to ensure the future competitiveness of
our country. We also request that you contact House Speaker Nancy
Pelosi to thank her for her tremendous efforts in ensuring that
science infrastructure investments were included in the House
stimulus package, formally known as the .American Recovery and
Reinvestment Act of 2009.. You can make these contacts quickly
and easily at:

There, you will find pre-written messages to your Senators and
Speaker Pelosi. You may send these letters as they are, modify them,
or write your own. While individualizing your letter is not
essential, please at least make minor edits to the subject line
and the first line of the text of each email so that these emails
are more individualized. (See webpage pointers below for further

As you may be aware, the U.S. Congress is currently formulating a
stimulus package to help spur the recovery of our economy. In
addition to the tax cuts in the draft packages being discussed,
the packages include a number of infrastructure investments that
would create millions of jobs.

APS has actively participated in this process by providing the
incoming Obama Administration, and the leadership in the House and
the Senate, with recommendations for investments in scientific
infrastructure that would create more than 100,000 direct and
indirect jobs. The investments we proposed are principally in
infrastructure in our national laboratories and universities, high
performance computing, in procurements of scientific instruments
and material for projects such as ITER, and in creation of jobs for
young investigators at our universities to ensure that they have a
place to go during these trying economic times. As a result of our
efforts, many of our recommendations were used by the House and
Senate in formulating their proposed stimulus packages.

On January 15th, the leadership of the House of Representatives
proposed a bill that would give a significant boost to science
infrastructure, including allocating $2 billion for the Department
of Energy Office of Science (OS), $2.5 billion for the National
Science Foundation (NSF), $500 million for the National Institute
of Standards and Technology (NIST) and $100 million for advanced
computing. On January 23rd, the Chairman of the Senate
Appropriations Committee released a summary of a proposed Senate
stimulus package. Unfortunately, the announcement did not offer
many details about how much funding science would receive in that
package. However, we are receiving troubling signs that science
may not receive the same levels of funding as in the House package
and would even, in some scenarios, be cut or even eliminated. We
are therefore urging the Senate to follow the House lead in helping
to ensure American competitiveness in the 21st century by making
critically needed infrastructure investments.

The attached letters would 1) thank House Speaker Pelosi for her
support of science and 2) request that the Senate follows the House
by including a robust amount of funding for scientific
infrastructure investments.

(1) While individualizing your letter is not essential, we ask that
you make minor edits to the subject line and the first line of
the text of each email.
(2) If you are a government employee, please do not use government
resources to send a communication.
(3) Your browser will take you to a page where you will enter your
name and address.
(4) After entering your address, click the .Edit/Send Email button..
A window with an individual email message to the four offices will
appear. Click .Send Emails. to transmit the communication.
(5) Electronic submission is preferred.

Not Taking it Personally

Chad discusses Editing and its Discontents over at Uncertain Principles.

At NIST, the paper-writing process was called “paper torture” for a reason, and it wasn’t that we were waterboarding our printed drafts. The process consisted of one author writing a draft, circulating it to everybody else, and then having a three-hour meeting in which every word of every sentence was challenged by somebody.

I have to admit, I had a slight tendency to take this personally. Not so much in a “my confidence in my ability to write well has been shattered” sense, though. More of a “how dare you criticize my deathless prose” kind of way. This probably dragged some paper torture sessions out longer than they needed to be, because my co-authors were almost always right, but having my drafts that I worked hard on cut to pieces always got my back up.

I’ve been fortunate that in my career, the group discussions giving feedback on papers or presentations have never gotten particularly rancorous — there is the occasional difference of opinion, but most of the time the author will admit that the suggestion makes the work better, or has some good reason for not making the change, and the matter is pretty quickly resolved. Everybody has their name on the paper, so there’s certainly motivation to put the best work out there as possible.

I had almost all of my tendency to take criticism personally beaten out of me while I was in the navy. If there’s one thing the military is good at, it’s generating leaders who are skilled at yelling at people for screwing up, but this goes even beyond that. The training to become a teacher included several practice lectures, after which the “students” (staff members observing and play-acting as necessary) gave critiques. And boy, was there criticism. (You’re facing the board. You’re mumbling. You keep saying, “So.” You’re doing that. You’re not doing this.) Realizing that the need to improve didn’t mean you were a bad person, and developing a thick skin, was pretty much mandatory. It was nice, though, when there was the occasional positive comment, and when reviewing I try to point out things done well, too, as well as picking at nits.

A Day in the Life

I was reading Wal-mart approach to college education? at incoherently scattered ponderings, and the latter half brings something to mind.

If you read comments to the article – one thing is for sure, regular people have no idea what faculty do all day long. Apparently the impression is that we teach a class (takes what – an hour three times a week?) and then we sit in our offices like fat cats eating donuts.

I know they don’t just sit around. But if the general impression is otherwise, how about a call for academic science bloggers to post a typical day, or chronicle a particular day that seems fairly typical. I see that Sciencewoman has provided a guest post recently. If you see this, consider yourself tagged and please do so, and also spread the word. If you already have at some time in the past, post a link in the comments.

Then You Are Set With a Capital 'J'

When you’re a Jet,
You … stay … a … Jet!

Why Dropping a Stone Makes a Jet

The splash of a solid object into water–be it a coin or an Olympic high diver–is capped off by a thin jet of fluid shooting straight up from the surface. The detailed explanation of this seemingly simple event has proved elusive. Now researchers publishing in the 23 January Physical Review Letters think they have a more complete explanation than their predecessors. Using a combination of theory, simulation, and experiment, they studied the collapse of the air cavity trailing the submerged object, concluding that it ejects water like toothpaste squeezed rapidly from its tube.

Phys. Rev. Lett. 102, 034502
(issue of 23 January 2009)

How Atomic Clocks Don't Work

I was listening to a podcast recently that delved into timekeeping and atomic clocks, and was surprised that they got a couple of details wrong. I haven’t done a post explaining how atomic clocks work, because that’s something easily found on the intertubes, and so I’m not particularly motivated to recreate Wikipedia or HowStuffWorks.

But someone was wrong on the internet, and the basis of that “wrongness” has some physics behind it. The claim was made in explaining clocks that when electrons absorb energy they jump up a level, and then radiate it when they jump back down. And while that’s true, it’s not the basis for a Cesium or Rubidium clock. The thing is that you don’t want the atom to radiate on its own if you are going to make a clock out of it. Transitions between atomic states are not infinitely narrow, i.e. there is an uncertainty in the energy of the emitted photon. This is known as the linewidth of the transition, and for a good clock you want a really narrow transition so that you know what the frequency is. While there are several factors that can increase that linewidth, the fundamental width is due to the Heisenberg Uncertainty relation between energy (or frequency) and time.

The uncertainty of the frequency and the lifetime of the transition are inversely related, and \(Delta omega Delta t = 1 \) (that should be greater than or equals, but latex is choking on that for some reason)

In order to get a narrow transition, you want a long-lived state. So you don’t want something that radiates readily on its own, and atomic clocks don’t. Cesium and Rubidium devices are passive: you shine radiation on them, and then read out whether or not your radiation was on resonance by looking at which state the atoms are in. Active masers do radiate, but as the acronym tells us, the radiation is stimulated, rather than being spontaneous. (Left on its own, the lifetime of the Hydrogen atom state is about 10 million years) The search for long-lived states becomes even more important for optical clocks, since the larger energy differences tend to lead to shorter lifetimes. What is generally done is to search for so-called forbidden transitions, in which the strong coupling of electric dipole transitions aren’t present, and you are left with other types of transitions or ones that must couple through other states and end up taking much longer.

Happy Blogoversary to Me

How do you measure yourself against other bloggers?
By height.

Wow. I’ve been doing this for a whole year.

It’s not surprising that I started at this time of year, since the football season is mostly over and there’s a huge gap in the day wanting to be filled, and the weather isn’t consistently good enough to expect to be outside much. I had kicked around the idea of blogging for a little while, once I realized there were blogs out there that weren’t political rants or diaries, neither of which hold must interest for me.

And, of course, it’s a work in progress. My idea of what the blog should be about has morphed over time as I discovered how much harder it is to write (hopefully good) posts than I naively thought it would be. It doesn’t help that my general niche in physics (atomic) was already very ably occupied by Uncertain Principles, so even if I were capable of discussing atomic physics as well as Chad, there still wouldn’t be much point in covering the same ground. The more popular aspects of physics would run me up against Jennifer at Cocktail Party Physics (now with several other contributors) and later Twisted Physics. The discussion of cornerstones of physics is better left to those teaching it, as Built on Facts and Dot Physics do so well. I’m not going to blog about particle physics, condensed matter, or any of the other disciplines within physics. Other physics blogs that survey the physics news use pretty much the same sources that I do, so there’s no new ground there — you have to comment on it sometime to add value. (And I’ve only mentioned a small slice of the blogs out there. No slight intended by that or the fact that I probably need to update my blogroll)

I’m also a little bit hobbled by working where I do — the government, especially the military, have rules. If it’s classified, you can’t talk about it. If it’s not classified, you still can’t talk about it, because it might still be sensitive; you have to wait until it’s cleared for official release. (Anything I’ve posted specifically having to do with my technical work has been published somewhere). I’ve been doing quite a bit of administrative work in the last few years, and even when I can spend time on the atomic clock project, there’s the tunnel vision that sets in — focusing only on the project and things immediately related to it. I try to keep my head in the game by discussing physics online, particularly at this blog’s host and occasionally elsewhere, but refuting crackpots gets old and repetitive. I don’t work in academia, so there isn’t that experience to draw upon; the teaching experience I have has some limited relevance, but not a lot.

So I’ve tried to carve out another niche. Blogging gives a different perspective, and forces me to go out and see what’s going on in the world of physics. I think I’ve read more papers because of blogging than for work this past year. I also like technology and weird things, so I’m going to find those links anyway, but at least now I feel like it’s not a waste of time to do so, since I share. I like learning about those little do-it-yourself science projects, and I’ve added a DIY science category)


I went over 1000 posts sometime in mid-December. Not as impressive as it sounds, though, because my links tend to each be in a separate post. Almost 50,000 visitors. That number is a little uncertain because the stats counter wasn’t in place when I first started.

What I’ve observed:

Writing posts or email when you’re sick is a bad idea. There’s too much “The hell? Why did I say that? I’m an idiot!” involved. At least post drafts can be deleted, and you can start over.
Writing well is hard. When you’re explaining things to a person you get feedback to let you know if you’re being effective.
I often think of something to add after I’ve posted that would have made it just that much better. Call it blogger’s remorse.

Ok, then. Back to the physics, the geekdom, and the nonsense.

I'm not a Mathematician, but I Play One on TV

Calculus and “The Method”

A Prayer for Archimedes

Two of the texts hiding in the prayer book have not appeared in any other copy of Archimedes’s work, so no one but Heiberg had studied them until now. One of them, titled The Method, has special historical significance. It could be considered the earliest known work on calculus.

Archimedes wrote The Method almost two thousand years before Isaac Newton and Gottfried Wilhelm von Leibniz developed calculus in the 1700s.