On 1/3/2016 10:11 AM, Mark Lloyd wrote:
On 01/02/2016 11:22 PM, Don Y wrote:

(the leap year cycle repeats every *400* years, not every 4)

So the average year is 365.2425 days long (365 + 1/4 - 1/100 + 1/400).
Interestingly, that is a whole number of seconds (31,556,952).

Of course, that doesn't count the unpredictable leap seconds.

The notion of a "day" varies, over time as the earth's rotation
is slowing. So, the need to keep injecting MORE extra seconds.

Of course, no one has told any of our (traditional) clocks about
this...

[Hand-waving to ignore annual variations in the length of the
"solar day"]

I wonder if the early "celestial mechanics" (galileo, newton,
kepler, copernicus, etc) would have ABANDONED their ideas had
they known EXACTLY how weird it all ACTUALLY is??