Time keeps on slippin', drippin', meltin', into the future
December 5, 2016 10:57 AM Subscribe
As you look to the end 2016, you might think of New Years Eve celebrations, including the iconic Times Square Ball, "probably the greatest single moment of public timekeeping in the world." Digging in, you'll find that it's really just a glorified time ball, an antiquated tool for sea-farers to set their chronometers and discern their longitude by means of celestial navigation. The first time ball went into use 1829, pretty late in the time-keeping game, so let's re-fill the ol' water clock and take this way back.
For a general overview, you may enjoy perusing the article and links in the Wikipedia article History of timekeeping devices. Therein you will find that we go back to 3000 to 2000 BCE when we can thank the Sumerian numeration systems for time-keeping in a sexagesimal system (which later lead to dividing a circle into 360 degrees). The question of "why base 60?" is trickier, and there are a number of theories (previously), but this still doesn't get us to any record of time-keeping devices.
For that, we go to Egypt, where they used the 12-part division of the day, which may or may not have come from the Sumerians and Babylonians. But to track time, the Egyptians used obelisks as early as 3500 BCE, and shadow clocks, possibly the first portable timepiece, came into use around 1500 BCE, both serving as early forms of sundials. The merkhet, ca. 600 BCE, was used for telling time at night, if one could see the stars (3 page PDF). Additionally, Egyptians are credited with developing water clocks, which reliably tell time at any time of day or night, so long as you remember to refill the vessel. Earliest documentation dates to c. 1417-1379 BCE, during the reign of Amenhotep III (Google books preview).
Greeks also used water clocks, known as clepsydra ("water thief" or "to steal water"), starting around 325 BCE to time speeches in courts of law. Ctesibius invented the first artificial automatic self-regulatory system when he improved on clepsydra, and the Anaphoric Clock was another improvement upon the basic design. Roman timekeeping advanced from there, adopting the 24 hour day (with "flexible" hours depending on the time of the year) and time tracking with sun dials and water clocks. Heading east and ahead some centuries, we get to Su Song (1020–1101 CE), the renowned Hoklo Han Chinese polymath who spent eight years making an amazing water clock, 40 feet tall and quite accurate due to internal mechanisms, known as the Astronomical Clock Tower or Cosmic Engine. Likely ahead of Song was Alī Ibn Khalaf al-Murādī (previously), a mechanical engineer who increased known gear complexity greatly, but still relied on water and mercury to drive the mechanisms in the 11th century AD. He documented his work in The Book of Secrets (12 minute mini-documentary on YouTube, a trailer of sorts for Leonardo 3's translation and model re-creation efforts).
Turning back time to look at another time-keeping device, the history of sand clocks and hour glasses is uncertain, despite prior assumptions that Athenians were carrying small sand timers around like people now carry watches (Archive.org), except Late Bronze Age glass was a luxury item and it wasn't until second century CE that the use of glass spread throughout the Middle East and beyond. Lacking other records, the earliest confirmed sand timers have been identified through artistic representations. The earliest such record is a carved arcophagus dated c. 350 CE, representing the wedding of Peleus and Thetis, where Morpheus appears to be holding an hourglass, and then when glass-making methods were lost, so did representations of hourglasses. The next depiction is of Temperance holding a large hourglass from 1338. Because they don't freeze, aren't prone to setting things on fire, and are fairly reliable (Gbp), marine sandglasses were commonly used by seafarers in the 14th century .
There are also few forms of "fire clocks" that burn or smoulder to track time, including a variety of candle clocks (one of the earliest references to them appeared in a Chinese poem by You Jiangu A.D. 520 -- Gbp) and later (whale) oil lamp clocks that built upon a long history of oil lamps (again with a murky time-line, but oil lamp clocks were mainly used in the 18th century), as well as incense clocks of simple and more complex forms have been traced back to China between the years of 960-1279.
The history of mechanical clocks is contested, like so many other records of horological firsts, in part because the naming of these time-keeping devices was far from certain. It wasn't until the 14th century the term "clock" (possibly back to Old Irish clocc, Welsh cloch, Manx clagg, meaning "bell"), came into being. Previously, a time keeping device was a dægmæl (from dæg "day" + mæl "measure, mark") in Old English, and the Latin horologium, though horologe was also in use in the 14th century, while chronometer dates to 1714 to broadly describe time-tracking devices, not specifically portable marine time-keepers used to track longitude.
The first mechanical clocks came from the same inspiration as the old Egyptian water clocks: attending to religious obligations and other duties in a timely fashion, day after day. The Moors of Spain are credited to bringing the inspiration for weight-powered clocks to Europe (Gbp), but it was Father Gerbert, who worked with Muslim intellectuals, developed the first weight driven clock, for the University of Magdeburg in 996 CE. After the weight-driven clock (not clear if it utilized a pendulum or other mechanism) made by Gerbert, who would become Pope Sylvester II, the next remaining records indicate that the use of other mechanical clocks resumed in Monasteries in Europe in the 11th century (Gbp). Another old reference to a mechanical clock can be traced to Dunstable Priory in 1283, where the chronicler of the Annals of Dunstable Priory reported In the same year we made the ”horologium” which is placed above the ”pulpitum”. Others point to Dante's Paradiso and it's mention of "the horologe" (with an alternate translation referring to "a clock’s machinery") to indicate that clocks were fairly common in Italy by the early 1300s, and thus suggesting to some historians that Italy likely served as the birth-place for modern mechanical clocks.
In a 23 page write-up on Richard of Wallingford, Abbot of St. Albans, 1326-1335 (PDF) for the sixth centenary of his election to the high office of Abbot, there is a section on his early clocks. The Salisbury cathedral clock (c. 1386) is frequently credited as the oldest mechanical clock (still in use), though two others also claim this title (Gbp): the clock in the bell tower of San Gottardo in Milan, Italy, is believed to have been built around 1330, and an understated clock in Cathédrale Saint-Pierre de Beauvais is claimed to have chimed since 1305, though most eyes are fixated on the astronomical clock. This is the masterwork of clockmaker Lucien Auguste Vérité and 9 other clock makers, plus an additional 10 men, who worked together for four years to create the clock (Scientific American, transcription of the original article from 1869). Vérité unveiled the clock at the Palais de l'Industrie in Paris in 1869 and installed in the cathedral in 1873.
Besides the immense complexity of the astronomical clock, it also features a major advancement in time-keeping over its predecessor: a pendulum. Galileo Galilei had the idea for the mechanism around 1637, but in 1656 Christiaan Huygens constructed the first working pendulum clock. As he refined the design, by 1690, accuracy was close enough that minute hands were regularly being added to the clock face.
Unfortunately, it didn't solve the long-standing problem of determining longitude, which would lead to a number of significant "longitude rewards" that further focused scientific attention on the problem. Huygens tried to make a pendulum-driven clock work for sea travel by studying the movements of the pendulum, to resolve the longstanding problem of how to determine longitude at sea. While his studies lead to the first-ever observation of what physicists call coupled oscillation, he was unable to make a pendulum clock durable enough for rough seas, so he turned his attention to writing his master piece: Horologium oscillatorium: sive de motu pendulorum ad horologia aptato demostrationes geometricae (Latin: The Pendulum Clock: or geometrical demonstrations concerning the motion of pendula as applied to clocks). You can read a copy online, translated and annotated by Ian Bruce.
John Harrison, a self-educated English carpenter and clockmaker, was the individual who finally invented the marine chronometer, starting designs in 1730. 99 years later, the first time ball dropped at Portsmouth, England to serve as a public time signal. The Portsmouth time ball predates the Time Ball at the Royal Observatory in Greenwich, which first operated in 1833 to announce the time to ships on the Thames and many Londoners, and still operates daily, dropping to signal 1pm GMT. Before time balls, cannons have served a public time-keeping purpose, as heard with the Noon Gun in Cape Town, South Africa, which has operated since 1806. But to be really accurate in keeping time via sound signal, you had best confer with a time-gun map to correct for "sound seconds" (Gbp). Cannons and time balls were replaced in by radio signals, whose frequencies were made more accurate with quartz crystal piezoids, which leads us to the next improvement to time-keeping.
But first let's talk about when to mark time. As the sun rises and sets continuously around the globe, it would make sense that the start of the day is a localized point in time, and this was very much the fact until "railway time" was set by the Great Western Railway in England in November 1840, the first recorded occasion when different local times were synchronised and a single standard time applied, though roll-out took a few years. North America followed up in 1883 with Railroad and Telegraph Time, and on the 1st of May 1909, the Amsterdam Time or Dutch Time was introduced in the Netherlands, again to support rail travel timing. Time zones were becoming a standard around the world.
It would be almost another 200 years after John Harrison started working on The Clock That Changed the World (BBC History of the World documentary) that clock-making made another great leap forward with the mechanical resonance of a vibrating crystal of piezoelectric material. As told by Warren Marrison of Bell Telephone Laboratories, who developed the first quartz-crystal clock, it was not a spontaneous discovery but involved the putting together of a considerable number of ideas that had been accumulating through a century or more of related activity. Marrison went on to state that "early as 1866, the essential elements had been developed separately from which a clock of the electric oscillator type could have been constructed," and in fact tuning fork clocks were designed and used starting in 1866, but to demonstrate frequency ratios for sound and pitch and later likely used to precisely tune the forks and other pitched instruments.
Similarly, atomic clocks have significant history leading up to their final development and deployment. In fact, in 1879 Lord Kelvin wrote that the period of vibration of a piece of quartz crystal of a specified shape and size and at a stated temperature ... gives us a unit of time which is constant through all space and all time, and independent of the earth and
If you go back in time, you can visit the Time Museum Collection, a former exhibit at the Museum of Science and Industry in Chicago, which has some interesting information online.
Bonus links for you old nautical types: Rules, Questions and Answers in Navigation by C.S. (Christopher Sickler) Street, D.D.S., who also wrote Useful Navigation for Power, Steam and Sailboat Yachtsmen (both are free eBooks via Google Books, as they were both published in 1917).
For a general overview, you may enjoy perusing the article and links in the Wikipedia article History of timekeeping devices. Therein you will find that we go back to 3000 to 2000 BCE when we can thank the Sumerian numeration systems for time-keeping in a sexagesimal system (which later lead to dividing a circle into 360 degrees). The question of "why base 60?" is trickier, and there are a number of theories (previously), but this still doesn't get us to any record of time-keeping devices.
For that, we go to Egypt, where they used the 12-part division of the day, which may or may not have come from the Sumerians and Babylonians. But to track time, the Egyptians used obelisks as early as 3500 BCE, and shadow clocks, possibly the first portable timepiece, came into use around 1500 BCE, both serving as early forms of sundials. The merkhet, ca. 600 BCE, was used for telling time at night, if one could see the stars (3 page PDF). Additionally, Egyptians are credited with developing water clocks, which reliably tell time at any time of day or night, so long as you remember to refill the vessel. Earliest documentation dates to c. 1417-1379 BCE, during the reign of Amenhotep III (Google books preview).
Greeks also used water clocks, known as clepsydra ("water thief" or "to steal water"), starting around 325 BCE to time speeches in courts of law. Ctesibius invented the first artificial automatic self-regulatory system when he improved on clepsydra, and the Anaphoric Clock was another improvement upon the basic design. Roman timekeeping advanced from there, adopting the 24 hour day (with "flexible" hours depending on the time of the year) and time tracking with sun dials and water clocks. Heading east and ahead some centuries, we get to Su Song (1020–1101 CE), the renowned Hoklo Han Chinese polymath who spent eight years making an amazing water clock, 40 feet tall and quite accurate due to internal mechanisms, known as the Astronomical Clock Tower or Cosmic Engine. Likely ahead of Song was Alī Ibn Khalaf al-Murādī (previously), a mechanical engineer who increased known gear complexity greatly, but still relied on water and mercury to drive the mechanisms in the 11th century AD. He documented his work in The Book of Secrets (12 minute mini-documentary on YouTube, a trailer of sorts for Leonardo 3's translation and model re-creation efforts).
Turning back time to look at another time-keeping device, the history of sand clocks and hour glasses is uncertain, despite prior assumptions that Athenians were carrying small sand timers around like people now carry watches (Archive.org), except Late Bronze Age glass was a luxury item and it wasn't until second century CE that the use of glass spread throughout the Middle East and beyond. Lacking other records, the earliest confirmed sand timers have been identified through artistic representations. The earliest such record is a carved arcophagus dated c. 350 CE, representing the wedding of Peleus and Thetis, where Morpheus appears to be holding an hourglass, and then when glass-making methods were lost, so did representations of hourglasses. The next depiction is of Temperance holding a large hourglass from 1338. Because they don't freeze, aren't prone to setting things on fire, and are fairly reliable (Gbp), marine sandglasses were commonly used by seafarers in the 14th century .
There are also few forms of "fire clocks" that burn or smoulder to track time, including a variety of candle clocks (one of the earliest references to them appeared in a Chinese poem by You Jiangu A.D. 520 -- Gbp) and later (whale) oil lamp clocks that built upon a long history of oil lamps (again with a murky time-line, but oil lamp clocks were mainly used in the 18th century), as well as incense clocks of simple and more complex forms have been traced back to China between the years of 960-1279.
The history of mechanical clocks is contested, like so many other records of horological firsts, in part because the naming of these time-keeping devices was far from certain. It wasn't until the 14th century the term "clock" (possibly back to Old Irish clocc, Welsh cloch, Manx clagg, meaning "bell"), came into being. Previously, a time keeping device was a dægmæl (from dæg "day" + mæl "measure, mark") in Old English, and the Latin horologium, though horologe was also in use in the 14th century, while chronometer dates to 1714 to broadly describe time-tracking devices, not specifically portable marine time-keepers used to track longitude.
The first mechanical clocks came from the same inspiration as the old Egyptian water clocks: attending to religious obligations and other duties in a timely fashion, day after day. The Moors of Spain are credited to bringing the inspiration for weight-powered clocks to Europe (Gbp), but it was Father Gerbert, who worked with Muslim intellectuals, developed the first weight driven clock, for the University of Magdeburg in 996 CE. After the weight-driven clock (not clear if it utilized a pendulum or other mechanism) made by Gerbert, who would become Pope Sylvester II, the next remaining records indicate that the use of other mechanical clocks resumed in Monasteries in Europe in the 11th century (Gbp). Another old reference to a mechanical clock can be traced to Dunstable Priory in 1283, where the chronicler of the Annals of Dunstable Priory reported In the same year we made the ”horologium” which is placed above the ”pulpitum”. Others point to Dante's Paradiso and it's mention of "the horologe" (with an alternate translation referring to "a clock’s machinery") to indicate that clocks were fairly common in Italy by the early 1300s, and thus suggesting to some historians that Italy likely served as the birth-place for modern mechanical clocks.
In a 23 page write-up on Richard of Wallingford, Abbot of St. Albans, 1326-1335 (PDF) for the sixth centenary of his election to the high office of Abbot, there is a section on his early clocks. The Salisbury cathedral clock (c. 1386) is frequently credited as the oldest mechanical clock (still in use), though two others also claim this title (Gbp): the clock in the bell tower of San Gottardo in Milan, Italy, is believed to have been built around 1330, and an understated clock in Cathédrale Saint-Pierre de Beauvais is claimed to have chimed since 1305, though most eyes are fixated on the astronomical clock. This is the masterwork of clockmaker Lucien Auguste Vérité and 9 other clock makers, plus an additional 10 men, who worked together for four years to create the clock (Scientific American, transcription of the original article from 1869). Vérité unveiled the clock at the Palais de l'Industrie in Paris in 1869 and installed in the cathedral in 1873.
Besides the immense complexity of the astronomical clock, it also features a major advancement in time-keeping over its predecessor: a pendulum. Galileo Galilei had the idea for the mechanism around 1637, but in 1656 Christiaan Huygens constructed the first working pendulum clock. As he refined the design, by 1690, accuracy was close enough that minute hands were regularly being added to the clock face.
Unfortunately, it didn't solve the long-standing problem of determining longitude, which would lead to a number of significant "longitude rewards" that further focused scientific attention on the problem. Huygens tried to make a pendulum-driven clock work for sea travel by studying the movements of the pendulum, to resolve the longstanding problem of how to determine longitude at sea. While his studies lead to the first-ever observation of what physicists call coupled oscillation, he was unable to make a pendulum clock durable enough for rough seas, so he turned his attention to writing his master piece: Horologium oscillatorium: sive de motu pendulorum ad horologia aptato demostrationes geometricae (Latin: The Pendulum Clock: or geometrical demonstrations concerning the motion of pendula as applied to clocks). You can read a copy online, translated and annotated by Ian Bruce.
John Harrison, a self-educated English carpenter and clockmaker, was the individual who finally invented the marine chronometer, starting designs in 1730. 99 years later, the first time ball dropped at Portsmouth, England to serve as a public time signal. The Portsmouth time ball predates the Time Ball at the Royal Observatory in Greenwich, which first operated in 1833 to announce the time to ships on the Thames and many Londoners, and still operates daily, dropping to signal 1pm GMT. Before time balls, cannons have served a public time-keeping purpose, as heard with the Noon Gun in Cape Town, South Africa, which has operated since 1806. But to be really accurate in keeping time via sound signal, you had best confer with a time-gun map to correct for "sound seconds" (Gbp). Cannons and time balls were replaced in by radio signals, whose frequencies were made more accurate with quartz crystal piezoids, which leads us to the next improvement to time-keeping.
But first let's talk about when to mark time. As the sun rises and sets continuously around the globe, it would make sense that the start of the day is a localized point in time, and this was very much the fact until "railway time" was set by the Great Western Railway in England in November 1840, the first recorded occasion when different local times were synchronised and a single standard time applied, though roll-out took a few years. North America followed up in 1883 with Railroad and Telegraph Time, and on the 1st of May 1909, the Amsterdam Time or Dutch Time was introduced in the Netherlands, again to support rail travel timing. Time zones were becoming a standard around the world.
It would be almost another 200 years after John Harrison started working on The Clock That Changed the World (BBC History of the World documentary) that clock-making made another great leap forward with the mechanical resonance of a vibrating crystal of piezoelectric material. As told by Warren Marrison of Bell Telephone Laboratories, who developed the first quartz-crystal clock, it was not a spontaneous discovery but involved the putting together of a considerable number of ideas that had been accumulating through a century or more of related activity. Marrison went on to state that "early as 1866, the essential elements had been developed separately from which a clock of the electric oscillator type could have been constructed," and in fact tuning fork clocks were designed and used starting in 1866, but to demonstrate frequency ratios for sound and pitch and later likely used to precisely tune the forks and other pitched instruments.
Similarly, atomic clocks have significant history leading up to their final development and deployment. In fact, in 1879 Lord Kelvin wrote that the period of vibration of a piece of quartz crystal of a specified shape and size and at a stated temperature ... gives us a unit of time which is constant through all space and all time, and independent of the earth and
The time of vibration of a sodium particle corresponding to any one of its modes of vibration, is know to be absolutely independent of its position in the universe, and it will probably remain the same so long as the particle itself exists.It took 76 years for technology to make Lord Kelvin's ideas for precise time-keeping a reality. The first accurate atomic clock, a caesium standard based on a certain transition of the caesium-133 atom, was built by Louis Essen and Jack Parry in 1955 at the National Physical Laboratory in the UK, and others made further refinements in the following years and decades. And this brings us to the end of our brief tour through the history of time-keeping.
If you go back in time, you can visit the Time Museum Collection, a former exhibit at the Museum of Science and Industry in Chicago, which has some interesting information online.
Bonus links for you old nautical types: Rules, Questions and Answers in Navigation by C.S. (Christopher Sickler) Street, D.D.S., who also wrote Useful Navigation for Power, Steam and Sailboat Yachtsmen (both are free eBooks via Google Books, as they were both published in 1917).
What a sad time for timecube.com to be dead and gone. :(
posted by xedrik at 12:24 PM on December 5, 2016 [1 favorite]
posted by xedrik at 12:24 PM on December 5, 2016 [1 favorite]
And in other time news, Google is getting around the leap second by "smearing" it across the first and last ten hours of 2017 and 2016 respectively.
How you'd put it on a bagel is left as an exercise for the reader.
posted by Talez at 12:27 PM on December 5, 2016 [1 favorite]
How you'd put it on a bagel is left as an exercise for the reader.
posted by Talez at 12:27 PM on December 5, 2016 [1 favorite]
Beautiful post! Thank you so much.
One thing I'm really fond of is the Western Union Self-Winding Clock, which was a service provided by Western Union in the early 20th century.
WU would send a one-second electrical pulse over a dedicated line at :59:59 Naval Observatory time to slam the clock's minute hand to the top of the hour. Releasing the signal at :00:00 would let the clock run freely again.
WU ran this service up until the 1960s from all accounts. There were also clocks that were placed in schools, hospitals etc that used a local master clock, like the IBM ones or the Simplex ones.
If you're feeling nostalgic, you can pick up a repro IBM today.
posted by JoeZydeco at 12:39 PM on December 5, 2016 [4 favorites]
One thing I'm really fond of is the Western Union Self-Winding Clock, which was a service provided by Western Union in the early 20th century.
WU would send a one-second electrical pulse over a dedicated line at :59:59 Naval Observatory time to slam the clock's minute hand to the top of the hour. Releasing the signal at :00:00 would let the clock run freely again.
WU ran this service up until the 1960s from all accounts. There were also clocks that were placed in schools, hospitals etc that used a local master clock, like the IBM ones or the Simplex ones.
If you're feeling nostalgic, you can pick up a repro IBM today.
posted by JoeZydeco at 12:39 PM on December 5, 2016 [4 favorites]
Oh god, I remember being in an elementary school that had a master clock for all the clocks in the classrooms. For most of one year it was broken and not just wrong, but wrong by a random amount that would change every day. Like one day at 2 it would say 7:18 and the next day it would say 3:49. I think they did that just to fuck with us (which they were doing anyway).
posted by Melismata at 12:53 PM on December 5, 2016 [1 favorite]
posted by Melismata at 12:53 PM on December 5, 2016 [1 favorite]
Superlative post.
If you're feeling nostalgic, you can pick up a repro IBM today.
or you can buy the real thing for much less. if you get ambitious you can build a sync source from the networked microcontroller of your choice and a relay (which I should really get around to taking pictures of mine).
posted by Dr. Twist at 12:55 PM on December 5, 2016 [3 favorites]
If you're feeling nostalgic, you can pick up a repro IBM today.
or you can buy the real thing for much less. if you get ambitious you can build a sync source from the networked microcontroller of your choice and a relay (which I should really get around to taking pictures of mine).
posted by Dr. Twist at 12:55 PM on December 5, 2016 [3 favorites]
More like filthy time thief, with all thee amazing links to get lost in.
posted by tobascodagama at 1:39 PM on December 5, 2016 [1 favorite]
posted by tobascodagama at 1:39 PM on December 5, 2016 [1 favorite]
Also, I cannot let a mention of the Times Square ball drop pass without calling attention to Eastport, Maine's (previously) sardine and maple leaf drop.
posted by tobascodagama at 1:57 PM on December 5, 2016 [1 favorite]
posted by tobascodagama at 1:57 PM on December 5, 2016 [1 favorite]
And yet nothing on the mighty Shortt-Synchronome, the last of the mechanical time references. Accurate enough to detect changes in gravitation due to the moon and also keep electrical grids in synch. The display clocks are impressive, but the clever bit is hidden in the vacuum tank, where a metre-long Invar pendulum ticks out the seconds. Accurate to about a second a decade, they are one of the triumphs of toolmaking.
posted by scruss at 1:58 PM on December 5, 2016 [6 favorites]
posted by scruss at 1:58 PM on December 5, 2016 [6 favorites]
And yet nothing on the mighty Shortt-Synchronome, the last of the mechanical time references.
Fantastic, thanks for that information! I also left out a link to a Wikipedia link to the page of Astronomical clocks, specifically the Strasbourg clock that includes what is thought to be the first complete mechanization of the part of the computus needed to compute Easter, which is no small feat.
Also left out: Clock Cleaning and Repairing - With a Chapter on Adding Quarter-Chimes to a Grandfather Clock, by Bernard E. Jones (Google books preview).
tobascodagama: More like filthy time thief, with all thee amazing links to get lost in.
Watch out for The Clock That Changed the World, a half hour documentary on YouTube, which then suggests more related documentaries. I was going to include a few, but I stopped myself.
posted by filthy light thief at 2:50 PM on December 5, 2016 [1 favorite]
Fantastic, thanks for that information! I also left out a link to a Wikipedia link to the page of Astronomical clocks, specifically the Strasbourg clock that includes what is thought to be the first complete mechanization of the part of the computus needed to compute Easter, which is no small feat.
Also left out: Clock Cleaning and Repairing - With a Chapter on Adding Quarter-Chimes to a Grandfather Clock, by Bernard E. Jones (Google books preview).
tobascodagama: More like filthy time thief, with all thee amazing links to get lost in.
Watch out for The Clock That Changed the World, a half hour documentary on YouTube, which then suggests more related documentaries. I was going to include a few, but I stopped myself.
posted by filthy light thief at 2:50 PM on December 5, 2016 [1 favorite]
also in the news today:
New stability record for atomic standards (Press Release, Arxiv pdf)
Clocks In Spaaaacccceee
This post along with carter's post has me ticking along nicely today
posted by Dr. Twist at 3:46 PM on December 5, 2016 [2 favorites]
New stability record for atomic standards (Press Release, Arxiv pdf)
Clocks In Spaaaacccceee
This post along with carter's post has me ticking along nicely today
posted by Dr. Twist at 3:46 PM on December 5, 2016 [2 favorites]
New stability record for atomic standards (Press Release, Arxiv pdf)
He he.. "Dick Noise"
posted by mikelieman at 5:34 AM on December 6, 2016
He he.. "Dick Noise"
posted by mikelieman at 5:34 AM on December 6, 2016
Smashing post! Here's an epilogue that deals with the implications of measuring time so accurately: Time Too Good to Be True by Daniel Kleppner.
posted by whuppy at 7:06 AM on December 6, 2016
posted by whuppy at 7:06 AM on December 6, 2016
A decade ago, I had the good fortune to visit Greenwich with my devout uncle. I pointed to one of the Harrisons and told him he could keep his bones of the saints and pieces of the True Cross, this right here was a holy relic.
posted by whuppy at 7:13 AM on December 6, 2016 [1 favorite]
posted by whuppy at 7:13 AM on December 6, 2016 [1 favorite]
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Outstanding, filthy light thief.
posted by pjern at 11:09 AM on December 5, 2016