How much time is one second ?

Question

We all know the breakdown of time units till the second from minute and hour. But, can anyone tell me how much time is ONE second made up of ?

Answer 1

Under the International System of Units, the second is currently defined as the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium-133 atom.

For more history check the wikipedia link below.

Answer 2

From Wikipedia:
Under the International System of Units, the second is currently defined as the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium-133 atom. This definition refers to a caesium atom at rest at a temperature of 0 K.

I've also heard that it is the amount of time it takes for light to travel a certain distance in vacuum.

Answer 3

Of course there are 24 hours in a day and the earth makes one full rotation in that amount of time. The hour is further divided into 60 minutes and each minute is further divided into 60 seconds. The time contained within one second is therefore based on the amount of rotation the earth makes in that fraction of time. If the earth spun faster or slower, the amount of time in a second would differ for practical purposes. Of course if you visit the moon you could wear a watch manufactured for use on earth to keep time even though a 'day' on the moon would take about a month to transpire.

Answer 4

Time is defined as
"9 192 631 770 periods of the radiation involved in the transition between the two hyperfine levels of the ground state of the Cesium-133 atom at sea level."

There is such a thing as a smallest time interval, called Plank's time. It measures 5.39121 x 10^-44 second.

Therefore, a second is made up of (approximately) 1.855 x 10^43 such units.

Answer 5

Under the International System of Units, the second is currently defined as the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium-133 atom. This definition refers to a caesium atom at rest at a temperature of 0 K.

Sub-divisions are 1000 milliseconds, 1,000,000 microseconds, 1,000,000,000 nonoseconds, 1,000,000,000,000 picoseconds, etc.

Answer 6

In 1967 the Thirteenth General Conference on Weights and Measures defined the second of atomic time in the International System of Units (SI) as:

the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium-133 atom.

Answer 7

Under the International System of Units, the second is currently defined as the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium-133 atom. This definition refers to a caesium atom at rest at a temperature of 0 K.

Looks like I was beaten by about 91,926,317,700 periods of the radiation...

Answer 8

well there are thousands of ways to determine how much one second is. like 10 tenths of a second or 20 twentieths of a second. or 2 halves of a second. so no matter what it all equals one second. so pretty much there is no ONE way. same for other numbers. like 2 is 2 seconds or 4 halves of a second 8 fourths of a second.

Answer 9

All times are made up of certain numbers of an apparently indivisible unit called the planck time. In quantum physics, it has been found that in our universe no unit of time smaller than a planck time has any real meaning; effectively, the planck time is the basic unit of time. One second is approximately 10^43 planck times or thereabouts. Written out fully, that's about 10 000 000 000 000 000 000 000 000 000 000 000 000 000 000 planck times in every second.

While yes, the official definition of a second is as stated above, based on cesium atoms, even cesium atoms aren't perfectly accurate. The planck time, however, IS perfectly accurate, and personally I feel it would be more useful to define a second as being a certain number of planck times.

Answer 10

"The second is the duration of 9192631770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the cesium 133 atom."