Happy 42nd birthday, Leap Second!

The first atomic clock, at NIST. [Wikipedia]


The first atomic clock, at NIST. [Wikipedia]

It was on this date in 1972 that the first leap second was added to a day.

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Twins born a year apart on New Years eve

I was a midnight birth, born somewhere between 7/16/71 and 7/17/71 (the doctor let my mom choose my birthday). For New Years babies born around midnight, the choice is more momentous -- a whole year's difference! But what about New Years twin births? A woman in DC delivered her twins in two different years, three minutes apart. Cory 16

Long-form YouTube: videos of entire long-distance train journeys

YouTube has been an existence-proof of forms of video that were lurking in potentia, unable to come into existence due to limitations of the distribution channel. The two-to-three-minute video has now been firmly established as a genre (with the six-second video hot on its heels), but there's plenty of room at the long end of the scale. Case in point: subculture of YouTubers who post full-length train journeys, hours and hours' worth -- and if that's not long-form enough, how about 134-hour sea crossings?

Given the modern vogue/panic about short-reads being mere "linkblogging" and the practice of spinning out a few hundred words into a "serious, long-form journalism" wheeze that is split across eight or more screens, this may just be the video form for our age (and please let it be a short one!).

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Museum of Four in the Morning

"Four in the morning" appears with strange frequency in movies, TV, art, and culture. The Museum of Four In The Morning collects such references. Submit yours!

Enormous timescales made graspable by graphs

Wait But Why has a fantastic series of graphs that aim to help us wrap our heads around the enormous timescales on which forces like history, biology, geography and astronomy operate. By carefully building up graphs that show the relationship between longer and longer timescales, the series provides a moment's worth of emotional understanding of the otherwise incomprehensible.

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Christian Marclay's "The Clock" video montage

Pioneering sound/video collage artist Christian Marclay's "The Clock" (2010) is a 24-hour montage of appropriated film clips related to time. OK, I'll admit that I haven't seen the whole piece, but the chunks I've watched are fantastic. Above is a phonecam recording of some of it, recording at one of its installations. The Clock will be on view at the SFMOMA starting April 6, which is appropriate given the museum's imminent closure in June for (gasp) three years of construction. "SFMOMA Presents Christian Marclay’s 24-Hour Cinematic Masterpiece The Clock"

Grand Central Station's clocks are a minute off

Here's The Atlantic on how New York's busiest train station helps commuters get there in time: by giving them an extra minute: "The idea is that passengers rushing to catch trains they're about to miss can actually be dangerous -- to themselves, and to each other. So conductors will pull out of the station exactly one minute after their trains' posted departure times."

Hello, Curiosity

On Sol 32 (Sept. 7, 2012) the Curiosity rover used a camera located on its arm to obtain this self portrait. The image of the top of Curiosity's Remote Sensing Mast, showing the Mastcam and Chemcam cameras, was acquired by the Mars Hand Lens Imager (MAHLI). The angle of the frame reflects the position of the MAHLI camera on the arm when the image was taken. The image was acquired while MAHLI's clear dust cover was closed.

That's from NASA's description of this great Curiosity self-portrait.

What really stuck out to me, though, was the use of "Sol 32". Sol is what you call a "day" on Mars. We use a different word because the length of time is also a bit different. One Martian Sol is equal to 24 hours, 39 minutes, and 35.244 seconds. Sol 32 isn't, itself, a date, but simply a record tracking the number of sols that Curiosity has been on Mars—starting with Sol 0, which was August 6th. Every mission to Mars since Viking has kept its own sol count, so you can't really use these sol dates to keep track of history except as it relates to a specific mission.

There have, however, been proposals for a standardized Martian calendar system with a starting point that all dates progress from. NASA includes a Mars Sol Date on its Mars24 Martian clock app. In this case, the count begins on Earth date December 29, 1873 at noon Greenwich Mean Time and MSD represents the number of sols that have happened since then.

Why December 29, 1873? The Mars24 explainer just says that this date was chosen because it precedes all the really good, detailed observations of how time worked on Mars—how fast the planet was spinning, how often it went around the Sun, what the orbits of its moons were like ... that kind of thing. In 1877, the orbit of Mars took it particularly close to Earth, allowing humans—and their increasingly good quality telescopes—to get a really nice view of the planet.

That still doesn't exactly explain the 1873 date, though. But, according to Wikipedia, it's also the birthday of Carl Lampland, an American astronomer. Among other achievements, Lampland would calculate temperatures on the Martian surface, finding a large difference between soltime temperatures, and those at night. That data gave scientists their first clue that Mars had a particularly thin atmosphere, compared to our own.

Falsehoods programmers believe about time - riff on the malleability of computer time


"Falsehoods programmers believe about time" is InfiniteUndo's riff on Patrick McKenzie's classic Falsehoods Programmers Believe About Names. It's quite an eye-popping and mindbending riff on the malleability of time inside the world of computers, where a minute can last longer than an hour, where clients and servers may disagree about the time by an order of decades, and where production systems might routinely change timezones.

20. Time has no beginning and no end.

21. One minute on the system clock has exactly the same duration as one minute on any other clock

22. Ok, but the duration of one minute on the system clock will be pretty close to the duration of one minute on most other clocks.

23. Fine, but the duration of one minute on the system clock would never be more than an hour.

24. You can’t be serious.

Falsehoods programmers believe about time (via Making Light)

(Image: CASIO 593 A163WA-1QGF wristwatch, a Creative Commons Attribution (2.0) image from andresrueda's photostream)

Newly-discovered Mayan calendar in Guatemala proves (again) the world won't end in 2012

William Saturno, a Boston University archeologist, excavates a mural in a house in Xultun. Photo: Tyrone Turner © 2012 National Geographic


An archaeological expedition in the northeastern lowlands of Guatemala yields an amazing discovery: the "9th-century workplace of a city scribe, an unusual dwelling adorned with magnificent pictures of the king and other royals and the oldest known Maya calendar."

From Thomas Maugh's report in the Los Angeles Times, on the dig in the ruins of Xultun led by William Saturno of Boston University:

This year has been particularly controversial among some cultists because of the belief that the Maya calendar predicts a major cataclysm — perhaps the end of the world — on Dec. 21, 2012. Archaeologists know that is not true, but the new find, written on the plaster equivalent of a modern scientist's whiteboard, strongly reinforces the idea that the Maya calendar projects thousands of years into the future.

To paraphrase modern-day Maya priests I've spoken with on past travels in rural Guatemala: "Well, duh."

The findings were first reported Thursday in the journal Science. The full text of the report requires paid subscription, but a recent Science podcast covers the news, and is available here (PDF transcript or MP3 for audio).

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Excellent vintage film about the first accurate atomic clock

This short film was produced by the film unit of the UK's National Physical Laboratory (NPL) in the 1950s, and explains the principles behind the first accurate atomic clock, which was designed by Louis Essen and built at the National Physical Laboratory in 1955. The NPL's YouTube channel has other videos of interest to science geeks. (thanks, obadiahlemon)

Roger Ebert on losing friends

"We exist in the minds of other people, in thousands of memory clusters, and one by one those clusters fade and disappear." Rob

Time's twitterers of 2012

BB editors Xeni and Maggie feature on Time Magazine's 140 best twitter feeds. Adds Xeni: "they picked a tweet I wrote last night while utterly baked out of my fucking mind on medical cannabis."

Fun facts about the nature of time

Back in September, Discover Magazine blogger Sean Carroll assembled "Ten Things Everyone Should Know About Time" pulled from Setting Time Aright, a scholarly/scientific conference on the nature of time.

4. You live in the past. About 80 milliseconds in the past, to be precise. Use one hand to touch your nose, and the other to touch one of your feet, at exactly the same time. You will experience them as simultaneous acts. But that’s mysterious — clearly it takes more time for the signal to travel up your nerves from your feet to your brain than from your nose. The reconciliation is simple: our conscious experience takes time to assemble, and your brain waits for all the relevant input before it experiences the “now.” Experiments have shown that the lag between things happening and us experiencing them is about 80 milliseconds. (Via conference participant David Eagleman.)...

6. Consciousness depends on manipulating time. Many cognitive abilities are important for consciousness, and we don’t yet have a complete picture. But it’s clear that the ability to manipulate time and possibility is a crucial feature. In contrast to aquatic life, land-based animals, whose vision-based sensory field extends for hundreds of meters, have time to contemplate a variety of actions and pick the best one. The origin of grammar allowed us to talk about such hypothetical futures with each other. Consciousness wouldn’t be possible without the ability to imagine other times. (Via conference participant Malcolm MacIver.)

Ten Things Everyone Should Know About Time (via Kottke)

Submit your physics questions, win cool prizes

Tomorrow night at 9:00 pm Eastern, physicist Brian Greene will be speaking in New York City about ... well ... life, the Universe, and everything. He'll be joined via live link by theoretical physicist Leonard Susskind, and 2011 Nobel Prize winner Saul Perlmutter. It's part of the launch of Greene's new PBS series: NOVA: Fabric of the Cosmos. You can watch the NOVA episode anywhere. The live event will be streamed online starting at 10:00 pm Eastern.

Want to see the live event in person? You can't. It's sold out already. EXCEPT, here's the thing. The World Science Festival, which is cohosting the event, has a pair of confirmed VIP tickets set aside for a special BoingBoing reader.

How do you become special? It's easy. As part of the live event, Brian Greene, Leonard Susskind, and Saul Pearlmutter will be answering questions about all the weird and wiggly concepts that make physics so much fun, from dark matter, to the multiverse, to time travel. To get a crack at the VIP tickets, all you have to do is submit your question. Just post it here, in the comments, along with a mention of whether or not you live in the New York City area. I'll get the questions to the folks at the World Science Festival, and I'll pick one commenter (at random) to receive the free VIP tickets.

Don't live in New York City? Me, neither. That's why I'll also be drawing a second winner who'll receive a Fabric of the Cosmos DVD set.

You'll have until 10:00 pm central tonight to submit your questions.

Winners will be announced tomorrow morning, bright and early.

Image: Dark and ordinary matter in the Universe, a Creative Commons Attribution Share-Alike (2.0) image from argonne's photostream