The physics of timekeeping - with Chad Orzel
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- Опубликовано: 12 сен 2024
- Explore the physics that makes time something we can set, measure and know with physicist Chad Orzel as he discusses time from orbital motion and axial tilt to the quantum mechanics and relativity theory that gives us our ultra-precise atomic clocks.
Watch the Q&A: • Chad Orzel Q&A
Buy Chad's book, 'A Brief History of Timekeeping: The Science of Marking Time, from Stonehenge to Atomic clocks': geni.us/EBOLq
The need to tell the time connects you to over five thousand years of human history. From the first solstice markers at Newgrange to quartz crystal oscillating in your watch today.
In this talk, Chad explores the wondrous physics that makes time something we can set, measure and know.
Chad Orzel is an associate professor at the department of physics and astronomy at Union College, where he does research on atomic, molecular, and optical physics.
He has written for Forbes, Daily Mail and Physics World, and has spoken at numerous TED talks. His previous books have been translated into more than a dozen languages. He lives in Niskayuna, New York.
This talk was recorded on 3 February 2022
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Finally a Chad is giving a physics lecture what a time to be alive
Next a Chav.
Fly me away to 8
This comment was just top notch. 10/10.
Lame
Time is the most chad of science topics.
This is the best to the point no fluff compact history of timekeeping on youtube yet. Excellent pictorials. Dr. Orzel is a master lecturer. The kind you hope to find when you go to college. Check out his impressive credentials.
Thank you, sir. My wife has recently found these Royal Institution lectures and enjoys starting her day and waking her mind up to them. I am grateful for her happiness.
Keith Bowen
Very interesting lecture that covered things from a lot of fields. Its quite fascinating to think how much effort went into creating the systems we enjoy in the mdoern day.
commenting 29:40
As a photograper I learned, that the moon and the sun appear nearly the same size (that's why solar eclipses work),
and they virtually move their own diameter in a minute.
You can verify this watching a sunset, watching the time the sun touches the horizon until its gone.
When are you going to start hosting these lectures at the RI Theatre again? I miss that. :-(
Wow, how long was this video?
Oh how exciting! Great topic!
Impeccable introduction to time-timing GPS and the obvious evidence in support of Universal Positioning Systems, aka projection-drawing properties of Quantum Computational Holographic Principle Imagery, WYSIWYG pulse-evolution Perspective.
Interesting listing of the measurement of time!
I would like to add that there is also another artificial level of time through the human brain - expressed in music as 'rhythm'.
The interesting thing for me is that these rhythms can also be generated WITHOUT mechanical means (e.g. metronomes), only by the human brain - it would be worth researching this 'brain time' further ;-)
Even insects generate complex rhythms, some which rival trained human drummers specially many species of crickets
The watch Harrison is holding in the painting is not his chronometer H4. It's a watch made to Harrison's design by John Jeffries, and was never used as a marine chronometer.
Time is an illusion. Lunchtime doubly so.
So far I've very little about the part that tides must have played in the history of time keeping, particularly (I suggest) in the origin of the 12 hour clock.
I see something about the number twelve which specifically fits it for use in the so-called "rule of twelfths", a maritime rule of thumb still often used for estimating the height of the tide at any given time, and for when to expect the maximum and minimum speed of tidal flow. Starting with low tide this could tell you successively what proportion of the tidal range at any point during the spring-neap cycle had been reached at a given time until 6 at high tide, and while it recedes until 12 again. 1 o'clock tells you that 1/12 of the range has been reached, 2 o'clock that another 2/12 has been added (so increase in height and water flow is speeding up), at 3 o'clock that another 3/12 has been reached and we're now at maximum flow speed. By 4 another 3/12 has been added. The speed would be diminishing but the height would still be increasing till 6 when the tide starts to recede again. This change in flow speed is represented by the sequence 1 2 3 3 2 1, which of course sums to exactly 12. If the clock face were divided into 16 say, then the sequence would be 1 2 3 4 4 3 2 1 which sums to more than 16, and if 10 the sequence would be 12321 which sums to less than 10.
Tide, both high water and flow speed, must have been of immediate practical importance to early shore based and many riverine civilisations, enough to decide the number of time division units you were going to use.
You neglected to mention the need to adjust for time dilation. I think the adjustment is like 7 miles that has to be figured in.
Thanks for adding actual captions for the Deaf
I can't say Niskayuna or Worcestershire. Great Video!
The most interesting bit I've learned here is that "Ireland", as it turns out, is the cradle of civilization !
could a measure of the interval that virtual particles appear and then disappear be a possible mechanism of the ultimate clock, and would that be plank time based? If virtual particle creation/annialation timings vary between particular regions of space, that seems to offer a basic limitation to any possible clock accuracy.
a clock that will measure plank time is going to be our final satisfactory clocks
Love from Bangladesh.
Good one, how do we see mercury?
Thanks for the video and the different angles from which the topics we presented
I had some assumptions but they all tuned out to be false arguments
but my question is, is there any reason why to have months' days numbers as 28, 29, 30 or 31
1. is there reasons behind that?
2. leap year argument; 366 days in the year
though, there was no, a "plus" day / an actual more sun shine, as (In the Julian calendar, the average (mean) length of a year is 365.25 days.)
thus in 4 years, a complementary day pops up
Thanks in advance
Because Rome.
@@Josh-rn1em right, but my argument is; the .25 day in a year, is due to combining the day count to the time period;(24 hours) where a second is measured by a swing of the pendulum.
the result was in average 0.25 days per year, then they came up with the idea of adding up the 0.25s to get a whole day.
I think that could have been resolved if the time value of the second was reassessed.
there were reasons agreed upon, back then.
Thanks
@@mohamedselim6547 i get it. There is a better way. But the calander was made by a few people over time. Sept oct nove deca is 7 8 9 10. Because rome put june and july.
@@mohamedselim6547 No, no, the leap year has nothing to do with how we define the second.
One tropical year is 365.24217 mean solar days. This is simply the result of how Earth spins around itself while at the same time revolving around the Sun. A year is the time taken by Earth to revolve around the Sun. A day is the time taken by Earth to spin around itself (relative to the Sun). Neither is defined in terms of seconds. Their ratio-365.24217-is not a whole number. That ratio doesn't depend on the definition of the _second._ You can't change that ratio or make it a whole number by changing the definition of the _second_ or by using any other unit of time.
BTW, note that the fractional part is 0.24217, not 0.25. Every 4 years the fractional parts add up to _almost_ a full day: 0.96868, but not quite 1.0. So when we add the extra day in a leap year, we've added some extra 0.03 fraction of a day. In the Gregorian calendar, we correct for that also. Do you wanna know how?
@@nHans thanks for the response, and yes I would like to know.
This how I thought things go, the day is 24 hours; 60minutes each, a minute is 60 seconds (86,400 sec/day)
the time value of the second is "equal to the duration of 9192631770 periods of the radiation corresponding to the transition between the hyperfine levels of the unperturbed ground state of the 133Cs atom (Caesium).
Because the Earth's rotation varies and is also slowing very slightly, a leap second is added at irregular intervals to clock time[nb 1] to keep clocks in sync with Earth's rotation."
what makes time tick? black holes and gravity
Through the power of the speed of light I am first, in time!
By the Power of Grey Skull, I am He-Man!
As always! Great!
This is not one of RIs best presentations
What an idiotic thing to say US units are superior to IS units in this case. You say light travels about 1 foot / ns. Ok. I say light travels 30 cm / ns. I'm closer because the true number is 29,9792458 cm / ns and 1 foot / ns is 30,48 cm / ns.
My error is less than 0,0207542 cm / ns. Your error about 0,5 cm / ns. 25 times as large.
Good film, but, I hoped to see a good definition of time... (I mean coherent and complete)....Anyway a good material! My definition is that time measure change(s).
Is Time Timeless ? ?
time is the movement of energy.
Needs more frequency comb optical clock :)
The constant expansion of the universe. Without it we wouldn't have gravity
How can we truly measure time using physics that are bound by time? We are really only measuring perception of time, not the actual rate. If time speeds up or slows down for earth then clocks that exist on earth will move at the same rate they always have from our perspective..
Correct, you are always measuring time relative to a particular frame of reference. That is, your frame of reference.
Not perception, its true in absolute terms. Time is only relevant for where you are. Sure you can measure dilation between two points but which two points are you going to pick?
A man with a watch knows the time, a man with two watches can never be sure.
@@robthomas592 A man with three watches is cheating on his wife.
time is relative
*HA!* Destroyed flat-Earthers and geocentrists in the first few minutes and didn't stop the attacks till the end. I approve!
Some of my watches sync with atomic clock via radio waves every night. Casio G-Shock.
History* of timekeeping.
Get decent equipment and rerecord this It's hard nor expensive to make good recordings. Science!
Interestingly, there is no UTC GPS.
Chad Orzel, a very good history of man's time skilfully presented. you ended with atomic clock where nature's time start. man's ignorance of atom internal structure and function limit their understanding. you may like to know, In Persian science, it make it clear what make electron orbit nuclei or changes it's orbit. nature's time is event. one event lead to another lead to evolution of matter and physical world in universe. Ferydoon Shirazi MG1
Persian science? I don’t like the idea of the facts of science having a national identity. I prefer the concept that there is a single external objective reality we all share. The goal of science is to discover that reality.
0 Time is illusion.
1 Timing IS Real ~~ on mechanical Q. wheels.
You don't think of a sundial as a clock? I guess that's a language thing. In German:
clock = Uhr
sundial = Sonnenuhr
Sorry for being late.
Loads of Time.
Right.
Answer a spring and sprocket
How do we know the sun is exactly in Zenith? We know it's twelve a clock noon, fine. But how did sailors knew exactly when the sun was in zenith.
They used a sextant. It basically tells you the angle from the horizon to where the sun is.
Vessels which needed good measurements of position (e.g. naval vessels) did a fair amount of time reckoning even before the invention of the Naval Chronometer. The noon gun when they were leaving port set the reference and various clocks and watches on board were supplemented by hour-glasses. Simply counting the number of hours passed gave a good enough estimate of when noon occurred which could then be checked using a sextant or whatever instrument they had available. "Exact" in this context is a relative term.
Time only exists because people thought they wanted to have an excuse to have different ratios of different gearings.
Please no more Zoom presentations until the microphone issues are solved. They are really unwatchable. I am a huge fan of the channel so please do not take my comments as anything more than from a fan who doesn’t want to see the channel’s content not get out to those who really could use a bit of real scientific information in their lives.
Cant listen to this. Why do people from the US say 'ARRR' INBETWEEN EACH SENTANCE? There can be silence between a sentence. Don't know what it is that they cant have a break.
42:33 The imperial/US system is based on the metric system so that one foot corresponds to 0.3048 m and the International Committee for Weights and Measures in 1983 stablished that a meter is defined as the distance light travels in vacuum in one 299,792,458 th of a second. So it is the metric system that is defined using the speed of light and the American system is in turn based on that.
He was just pointing out what a happy coincidence it is, that light travels about one foot per nanosecond. He didn't say that anything is defined based on that! 🤣
But yeah, I can see that a small fraction of viewers could get confused by how he said it.
A couple of minor corrections to what you wrote:
- The Imperial and US Customary units are not _based_ on the metric system. They are both derived from even earlier English units. They have a long and independent history of their own.
- In the late 1800s, for reasons of practicality, the units of length and mass were _redefined_ in terms of the meter and kilogram respectively. But the new definitions did not change the units themselves.
- At present, it's actually the *_yard_* - not the foot - that's defined in terms of the meter: 1 international yard = 0.9144 meters exactly. This is consistent with 1 inch = 25.4 mm exactly and 1 foot = 0.3048 m exactly.
@@nHans
Then there is the International Foot, and the US survey foot.
I was hoping that he would’ve touched on sidereal time, Greenwich Mean time, and UTC. ((Leap seconds too. But, I’m greedy.))
@@larryscott3982 The International Foot is what the OP and I have been alluding to earlier. It's exactly 0.3048 m, which is exactly 1/3rd of the International Yard. Historically, there were many definitions of 'foot,' but at present, the two 'feet' that you mentioned are the only ones in official use in the US and elsewhere.
The good news is that the US survey foot is getting phased out starting in 2023.
Chad talks about leap seconds in the Q&A. And mentions Greenwich in the passing. Do watch it if you haven't; the link is in the description.
No doubt he could've talked a lot more. But if the talk gets too long, people lose interest rapidly. So it's best to break up such topics into multiple talks, and keep each one short and to-the-point. In that regard, it's fine that he didn't go into a deep-dive of tropical v. sidereal / Julian v. Gregorian / GMT, UT1, UTC / Daylight Saving etc.
@@nHans
There too much historical data in US Survey feet to really ‘phase it out’.
@@larryscott3982 Well, the legacy and historical records will be maintained as is-they won't be destroyed or overwritten by newer units! 😁
_'Phase out'_ means they'll stop using it for new measurements. New documents-such as newer editions of textbooks-will use the new units wherever possible. But when required, the old units will be mentioned as well, along with the conversion. Like we do for old Babylonian, Egyptian, and Roman writings. And the Bible. 🤣
I can give you India's example (I grew up in India). In the 1950s, India officially went metric. At that time, in addition to both metric and Imperial, India was also using traditional Indian units like _gaj, tola, gunta_ etc.
All these units were grandfathered, so that land records, property titles, legal documents etc. that used the earlier units continue to remain valid. The government provided official conversion factors for future use, but did not require all the existing documents to be rewritten.
Cool
Right? Right. right. Repeat.
Anybody can say /skəˈnɛktədi/ - you just have to spell it properly. Try writing "Skuhneckteddy." If you write _Schenectady,_ a lot of people-especially the British and Germans-will pronounce the _Sch_ as they do _Schitt's Creek._
Also, couldn't you just say that Schenectady is 15 minutes from the capital of New York State?
No, I guess that won't work-most people wouldn't know the capital of New York State; they probably think it's New York City. That's another weird aspect of America-the biggest city in the state is frequently _not_ the state capital. 🙄
CLOCKS
No offense, this is boring. Not the presenter, the topic I guess
Y'all really need to start sending these people a pair of apple wired headphones or something. The tinnie quality of this dudes mic is almost unbearable and the "Royal institute" should have higher standards.
Seriously, RI - Get good mics. The recording is terrible !
Do you even read comments? Do you care?
sounds perfect to me you better buy a new audio system
Hear hear it’s terrible
No use in thinking about a human concept "time" and what makes it "tick". Time simply IS, and you follow it's rules, whether you want to or not.
Please stop saying "uh" and "um". It's distracting and unprofessional. Your important presentation deserved better than to be polluted with verbal flotsam.
how about a swift kick in the nuts?
Sorry, but I'm dumping out after 16:18
i I um Um agh agh um um tik tok tik tok, um ugh agh agh. Write script, make a vid.
T I M E
Time is invented by clock companies to sell clocks
🤣 Generalizing the Hallmark holiday criticism beyond greeting cards, eh?
Actually, time was invented by Zoom to sell Zoom meetings.
For more than a decade now-since I started using mobile phones-I haven't used a stand-alone clock or clock-like device.
Unsubscribed…. Absolutely no reason for remote lectures. Poor graphics, visuals and audio. Stop denying young people of irl learning
HE PLAYS POKEMON GO
but what if the earth is not a sphere like believed in scientism, some researchers will argue differently look it up brother
🤣🤣🤣