I just thought of something yesterday evening.
Tuppence told us that the speed of light decreases(1) and that atomical processes decrease (or was it increase?) in speed as well.(2)
She also said that time measured by the sun and stars is constant.(3)
(3) Is not true.
[url:1ffbyfh6]http://tycho.usno.navy.mil/leapsec.html[/url] wrote:The Earth is constantly undergoing a deceleration caused by the braking action of the tides. Through the use of ancient observations of eclipses, it is possible to determine the average deceleration of the Earth to be roughly 1.4 milliseconds per day per century.
Days are getting longer, so the time measured by the sun is not that constant after all dear Tuppence.
[url:1ffbyfh6]http://tycho.usno.navy.mil/leapsec.html[/url] wrote:The length of the mean solar day has increased by roughly 2 milliseconds since it was exactly 86,400 seconds of atomic time about 1.79 centuries ago (i.e. the 179 year difference between 1999 and 1820). That is, the length of the mean solar day is at present about 86,400.002 seconds instead of exactly 86,400 seconds. Over the course of one year, the difference accumulates to almost one second, which is compensated by the insertion of a leap second into the scale of UTC with a current regularity of a little less than once per year. Other factors also affect the Earth, some in unpredictable ways, so that it is necessary to monitor the Earth's rotation continuously.
And don't say that this is only because of (2) because that is not true:
[url:1ffbyfh6]http://www.space.com/scienceastronomy/planetearth/millennium_time_991228.html[/url] wrote:These leap seconds are inserted on the advice of the International Earth Rotation Service (IERS) to ensure that, on average over the years, the sun is overhead -- that is to say at the zenith -- within 0.9 seconds of 12:00:00 UTC on the meridian of Greenwich. An international conference in 1884 placed the zero meridian at Greenwich, the basis for calculating mean time all over the world.
So if we would have used this defenition of the second:
The second was the tiny subdivision of Earth revolution, that is to say the 1/31,556,925.9747 of this revolution. for the past years,
then the sun wouldn't be exactly in the south anymore at noon.
So basicly all this says that (2) is not true since we have the atomical clock, which was invented in 1955.
Since Tuppence says that (1) and (2) are related and (2) did not change for the last 40/50 years, (1) did not change either.
I am very curious at what tuppence has to say on this....
*edit: fixed the quotes