Originally posted by joe shmo
Assuming a linear model, that is to say that the change in earths angular velocity per unit time remains constant ( which we cannot definitively say), the equation becomes in the format "VARIABLE_unit"
DAY_hrs = 6.289E-9_hrs/yrs*TIME_yrs + 23.9345_hrs
let day equal 24_hrs
solve for TIME_yrs
and I arrive at
TIME_yrs = 10,415,000
As to why it is slowing down, the simple answer is friction
I got a couple of answers, 8.5 million years and 17 million, which may be due to a mistake, since 8.5 X2 =17.
But friction from what?
Also, using the change in time, couldn't you theoretically figure out what year it was, like if you had a time machine, by very accurate timing of the length of the day?\
Using your figures of 10 million years to change by around 4 minutes, or 185 seconds, then the change per year would be one second every 50,000 years give or take, so 1/50,000 of a second per year roughly. About 6 E-13 seconds per second. I think modern atomic and photonic clocks and get that kind of accuracy.
I don't think you could do it in one second though, you would have to have an extremely accurate telescope and a clear sky to see that little change in whatever angular change that would represent. Like a 1 meter movement around a 1 parsec circle?
There is also the problem of events like yesterday's gigantic earthquake which slightly changes the length of the day all by itself by sending mass deeper and speeding up the rotation rate of the Earth.
We already add a leap second every 18 months or so as it is, that would really swamp out a 1/50000 ths of a second change in one year, being by definition about 75000 times larger an effect for an 18 month time frame.
I guess it would be easier to just use the telescope to chart the movement of constellations in the sky but that would not work for a 10 million year time frame since the night sky would be unrecognizable either 10 mil in the past OR future.