this is a time question?

Question

As we know it time is calculated at 24 hours in a day but I watched a tv program saying if time was calculated to the mili second there would actualy be 25 hours in a day it all had to do with the Sun or something like that Can anybody throw some light on this

Answer 1

I think you or the programme are a bit confused.

Here are some basic facts about time and the lengths of two important but different types of day:

The MEAN SOLAR DAY is defined to be 24 hours. By the way, time isn't "calculated at 24 hours a [mean solar] day" --- that's HOW the length of the conventional hour is SET, which is a quite different statement, logically.

It's the "mean [or average] solar day" because the Earth's angular speed in its orbit changes by about +/- 3.3% --- or about twice the orbital eccentricity --- during the course of this year. This means that the Earth is carried angularly a bit further along, or a bit less along, than needed to keep in strict synchronicity with its rotation in space.

Consequently, the time it takes the Sun to "rise to its highest point in the sky" on successive days varies. "Solar time" can be as much as some +/- 20 minutes out from the time shown by a perfectly regular clock. Ancient people were aware of this; a good sundial actually has a certain shape painted or carved on it (the analemma) showing the adjustment needed at different times in the year to obtain the "regularly proceeding" time of day. (The Greek astronomer Ptolemy entitled one of his books "The Analemma.")

The SIDEREAL DAY (time for one rotation of the Earth relative to the "fixed stars") is approximately 23 h 56 m 4.091 s on that same 24 hour mean solar day scale.

However, none of these FACTS*** [see my Postscipt, below] would alter one whit "if time w[ere] calculated to the mil[l]isecond." The statement that "there would actual[l]y be 25 hours in a day" because of that is a complete RED HERRING, an ABSURD NON SEQUITUR.

However, on the question of possibly REDEFINING the "hour" so that there would be 25 (new) "hours" in a day:

There are 96 quarters of an hour in a solar day. There was a suggestion during the French Revolution that the day should be divided into 100 units (each would have been 14.4 of our minutes long), with four of them being a revised "hour." That means that this new, "revolutionary hour" would have been only 57.6 of our conventional minutes long. (This suggested change was enthusiasm for a decimal system run amok.) In that case there WOULD have been 25 revised "hours" in the day. The suggestion, like several other suggestions for revising the calendar, never caught on, and was ultimately abandoned.

Live long and prosper.

*** POSTSCRIPT: I am a professional astrophysicist with a lifetime's interest in the subject of time. You can trust the information I'm giving you, unlike much of the conflicting information that has been included in many of the other answers.

Answer 2

Well, not 25 hours in one day, but 23 hours and 59 minutes is the correct length of a day (about). This is because the regular calendar does not calculate the length of an entire revolution around the sun perfectly. These miscalculations are combatted by not only leap year every 4 years, and then double leap year every 400, but also with minimal time changes at the change of a new year. At new year, a tiny change, milliseconds takes effect on each countries "megaclocks", clocks that run governments.

Answer 3

I dont think it is as drastic as 25 hours a day but it is over 24 hours a day. basically it takes the earth 365 days and 6 hours to orbit the sun, so theoretically a day is longer than 24 hours, thats why we have a leap day every 4 years

Answer 4

The solar day is 24 hours on average. I don't know where you got 25 hours from. The sideral day is slightly shorter by about 4 minutes.

A day on Mars, called a sol, is about 24 hours 37 minutes. Which is 25 hours rounded to the nearest hour.

Answer 5

You must have misheard - that would suggest an error of 1 in 24 for the current timing. However, we need adjust our timing by a little less than 1 day in every 4 years ==> 1 in 1460.

Could they have been suggesting that we went sort of decimal, without changing the value of an hour too much (4 days = 100hrs)?

Answer 6

lol you kinda made a pun. umm hrrm this just shows how much I've learned in Geography. I think because the earth go 'round 365.242 times *which is why we have leap year* that may cause hours in a day different...the earth also tilts at 23.5 degrees. Other wise I'm not sure...But it's some light.

Answer 7

the earth is round but peeps used to think it was flat so the sun is big and hot and BURNY. so we have daylight . if the earth was still flat then we would be peeps that live on a pizza world and the world would be called pizzaworld and we would all be pizza delivery peeps. mo ha ha haa . :}

Answer 8

somthing to do with the sun taking longer to go around the earth

Answer 9

I think it has to do with the extra day in every four years .. thus leap year .. maybe ..