The Metonic Cycle

The metonic cycle refers to a period of 19 years, which is the (approximate) least common multiple of days between a solar year (about 365.25 days) and a lunar month (about 29.5 days). Surprisingly, 19 solar years differs from 235 lunar months by only about 2 hours!

So, why is this relevant? Its Wikipedia entry yields a very interesting juxtaposition: “The cycle’s most significant contemporary use is to help in flight planning (trajectory calculations and launch window analysis) for lunar spacecraft missions as well as serving as the basis for the Hebrew calendar’s 19 year cycle.”

Nothing like bringing together the ancient and the modern through calendrical calculations.

The Best Writing on Mathematics 2010

The Best Writing on Mathematics 2010, edited by Mircea Pitici, is now available for pre-order. An article of mine from the Boston Globe is included in the collection, so I might be a bit biased about the quality of the included pieces, but there is some great stuff here: an essay by Freeman Dyson about how to categorize mathematicians; an article about a math museum; pieces about why we believe theorems and other aspects of the philosophy of math; and much more. Well worth checking out.

Work Habits of Highly Cited Scientists

In a recent paper in Scientometrics, a group of scientists examined what the social properties are of the most highly cited scientists in the fields of environmental science and ecology. They asked highly cited scientists (determined using to complete an online survey, and collected a wide variety of information, from demographics to perspectives on peer review.

The part that I found most intriguing was the analysis of work habits of these highly cited scientists. Specifically, they looked at how much time was spent on different categories of tasks, finding that these scientists spent about 25.5 hours per week on service-related tasks, and only about 23.5 hours on research activities. However, these highly cited scientists worked about 3.5 hours less overall than the average of those with doctoral degrees in their areas. In addition, the researchers looked at how much these high-impact scientists drink, finding an average of seven alcoholic drinks a week, which is 2.5 more than the average American.

Parker, J., Lortie, C., & Allesina, S. (2010). Characterizing a scientific elite: the social characteristics of the most highly cited scientists in environmental science and ecology Scientometrics, 85 (1), 129-143 DOI: 10.1007/s11192-010-0234-4

Birthdays and Google Searches

While the well-known birthday problem assumes an equal likelihood of being born on each day of the year, there is in fact slight, albeit statistically significant, variation in which days people are born on. I wanted to see if Google searches could be used as an indicator for this variation in births. Search behavior has been used to create indicators in the past, such as those for the flu, as well as a whole variety of financial and economic metrics (paper here), so why not for birthdays?

I compared birth data from 1994, binned into weeks, with Google Insights for Search data from 2009 for search interest in the word “birthday,” also binned by week. And, unfortunately, there is not a great correspondence:

Google search data explains less than 30% of the variation in the data, assuming that birth variation is constant each year. Apparently, people do not search for “birthday” on their own birthdays. A better indicator of birthday variation is likely its appearance on Facebook (or maybe Twitter), due to people wishing each other a happy birthday. Anyone want to try that analysis?

Where to Locate Your Super-Lair

Over at the so-amazing-it-shouldn’t-exist blog Law and the Multiverse about legal aspects of superheroes, there is a great discussion of where supervillains could legally locate their base of operations. The authors discuss various issues related to bases in three types of places: land, the high seas, and outer space. While space seems to be the location with by far the least legal complications, the land discussion ia quite intriguing:

You may be surprised to learn that there are a (very) few places left on Earth that are unclaimed by any sovereign nation.  Perhaps the most reasonable is Bir Tawil, a 770 square mile stretch of desert between the borders of Egypt and Sudan.  There isn’t a whole lot there, but at least it’s relatively close to more interesting places, and the neighbors are probably too concerned with their own problems to care about a supervillain moving in next door.

The Sounds of Christmas and Chanukah Songs

If I’m in a store or listening to the radio, I instantly know if a Christmas song is being played. And it’s not because of the words; it’s the bells. Bells in songs are quintessentially Christmas. Of course, there are exceptions–AC/DC’s Hells Bells is pretty clearly not a Christmas song–but it’s a useful rule of thumb.

The downside with Chanukah is that there is not a single aural indicator that it’s a song for the holiday. Sure, there are numerous Chanukah songs–e.g. Adam Sandler’s well-kn0wn song, the Maccabeats’ great parody of Dynamite called Candlelight that’s been making the rounds–but what Chanukah needs is a distinctive instrument to signal that a song is in the spirit of the holiday. While a shofar is certainly Jewish, it doesn’t quite have the musical versatility necessary for the task. I’m not entirely sure though what a good instrument would be. Perhaps the harpsichord can be the indicator of Chanukah music? Or the flute?

The Slippery New Year

With the New Year soon to be upon us, it is worth thinking about the nature of calendars. Many are familiar with the switch from the Julian to Gregorian Calendars, which involves a modification of the leap year (and during the initial switch, a shift of a several days in the calendar). This didn’t happen simultaneously throughout the world though; some countries persisted far longer than others in the Julian system. While the American colonies switched in 1752, Russia did not change over to the Gregorian calendar until 1918. This is why, despite being titled Red October, the Bolshevik Revolution occurred in November for much of the rest of the globe.

But another change was made slowly throughout the world, and far later than many might realize: the date of the New Year. While France adopted January 1 as the beginning of the calendar in 1564, Britain did not change over until 1752 (although New Year’s Eve still seems to have been celebrated prior to this on December 31), and Thailand did not adopt this change until 1941! Prior to these changes, December 25, March 1, September 24, and other days were used to begin the calendar. Genealogists, or anyone else interested in history, take note (astronomers seem to have dealt with much of this already): the very makeup of years have not always been what they seem.

Collective Nouns for Facts

We all know about collective nouns – those words for groups of things of a single kind. From a pride of lions and a gaggle of geese, to a fixie of hipsters, these terms conjure up wonderful imagery and fill gaps in our lexicon.

So, let’s say you have a bunch of facts; what do you call this? While it’s unclear what to say for a collection of substantive bits of information, for small and relatively unimportant facts, the choice is clear: a pursuit of trivia.