Swans on Tea

From Google Maps to Gold Medal
Kristin Armstrong, who won gold in the Women’s Individual Time Trial in Road Cycling, got a GPS track when she rode the Beijing Olympic course in December of 2007
After returning home to Boise, Idaho, I exported the GPS data to several different formats, one of which I was able to [...]

Or, in this case, the “not”
Why aluminum should replace cesium as the standard of time
The technique involved is neat: for some atoms you can find wavelengths where the AC Stark shift is the same for the two levels in the clock transition, so the atom is unperturbed by the presence of the trapping light. [...]

Analogy web clock.
via The Long Now

Why, yes, I can. I just happened to find an extra one floating around here.
The International Earth Orientation and Reference Systems Service (IERS) has announced a leap second.
A positive leap second will be introduced at the end of December 2008.
The sequence of dates of the UTC second markers will be:
[...]

Part I, Part II
Timekeeping measurements always rely on the comparison of two oscillators; when you check to see if your clock or watch is running fast or slow, you do this by comparing it to another clock. Finding disagreement between two clocks won’t tell you a priori which one is the culprit, just as [...]

There’s a video out there in the ether that purports to measure time dilation in a car. I’ve already shown that this can, and does, happen, but you need to have some pretty expensive toys at your disposal to make the measurement.
For a good experiment (I’m perhaps charitably assuming this wasn’t just an out-and-out [...]

Physics of GPS relativistic time delay over at Unused Cycles, yet another appears-to-be-new math-y/physics-y blog. Goes through the calculation of the gravitational and kinematic effects on GPS satellites.

(Part I)
The state-of-the-art timekeeping technology a century ago was comprised of pendulum clocks. Refinements were made in the areas of obvious problems, such as the mechanical escapement which robs the system of energy, the vulnerability to changes in length from temperature and humidity, and vibrations. The culmination of this was the clock of [...]

Following the suggestion and subsequent reminder (nothing like a deadline to get the creative juices flowing) from gg at Skulls in the Stars, I’ve got two “old” papers that I’m going to summarize.
I recommend choosing something pre- World War II, as that was the era of hand-crafted, “in your basement”-style science. There’s a [...]

Over at Skulls in the Stars
We want to put a sundial up on the new building on which I’ve been working. (sooooo close to being done, too). I had joked at one point that we would mount a light that would move around the gnomon, so you could read it at night. [...]

Second European Positioning Satellite Launched
Galileo, which should be operational by 2013, will be both an alternative and a complement to the U.S. Global Positioning System (GPS) and the Russian GLONASS.
There are some articles which call Galileo a competitor to GPS, which really isn’t the case; this article does a better job. I expect [...]

Bad Weather Makes for a Long Day
Changes in mass distribution affect the earth’s rotation rate. A little.
The National Institute of Standards and Technology in Boulder, Colo., occasionally adds a “leap second” to the atomic clocks used to standardize time. The last such update took place on January 1, 2006.
Arrg. And so do all [...]