Posted on 01/19/2018 10:32:02 AM PST by MtnClimber
Just what is a second, exactly? The question has been open to interpretation ever since the first long-case grandfather clocks began marking off seconds in the mid-17th century and introduced the concept to the world at large.
The answer, simply, is that a second is 1/60th of a minute, or 1/3600th of an hour. But that’s just pushing the question down the road a bit. After all, what’s an hour? That answer is related to the best means of time-keeping ancient civilizations had — the movement of the Earth through the heavens. The amount of time it takes for the Earth to turn once about its axis, or for it to rotate once about the sun, is fairly stable, and for much of human history, it sufficed as a way of marking the passage of time. Days, hours, minutes — they’re all just derivatives of planetary motion.
Today, however, when computers perform operations at the rate of 4 billion cycles per second, we need a better measure. The rotation of Earth, and its orbit, change slightly over time. Earth’s rotation, for example, is slowing slightly. So measuring a second based on rotation would mean that a second would get slowly longer over time. Ultimately, we couldn’t compare the second of today to the second of yesterday.
So, to pin down a truly timeless measure of a second, scientists in the 1950s devised a better clock, one based not on astronomical processes but on the movement of fundamental bits of matter — atoms — whose subtle vibrations are, for all intents and purposes, locked in for eternity. Today, one second is defined as “9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the cesium 133 atom”.
That’s a mouthful.
(Excerpt) Read more at blogs.discovermagazine.com ...
Probably for the same reason lonely rivers flow to the open arms of the sea.
“All measurements should mimic the decimal system.”
Get out of here, Frenchy!
Why are there 5 days to a work week.
That’s only in certain countries..........
LOL, THAT one I know well!
Call it whatever you want....won’t help my daughter get ready to go out any faster. ;)
Well they used to be the 7th, 8th, 9th and 10th months, when the Romans used a 10 month calendar. At that point, I think “December” just covered the entire winter, so they later split that up and created January and February.
“It is the amount of time it takes for a pendulum that is exactly one meter long to travel from one end to the other.”
Would that be different on the moon ? On Mars ? In space it would not swing at all.
Actually it is only on earth at sea level with an average barometric reading.
That’s because July and August were added in, Julius named after Julius Caesar, and August after Augustus.
Add a day to the Slack Week once every four years.
There are 12 months and 4 weeks per due women's cycles.
This occured once the light bulb went off in modern man's head, that PMS was what was causing all the problems in dealing with the "woman"
PMS was defined as Pre,Post and Present.
There was a "safe" unit of time that seemed to last the length of the other three. This coincided with the Moon phases; hence 4 weeks and 12 months. 12 seemed to be the reason for 12 am's and 12 pm's due to when woman was awake and asleep (peaceful time)
This is about the time that "man cave" was coined.
That is how man came up with the measure of time.
:)
Gravity always prevails.
Two “9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the cesium 133 atom”.
THree “9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the cesium 133 atom”.
Hmm, gonna be a while counting seconds from now on.
Yes, not as easy as “tic tock” any more.
Even the French have some things right...
I like it!
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