> after around 70 000 years if leap seconds continue to be added at the same rate
Apparently it's only 3000 years:
"Leap seconds are not a viable long-term solution because the earth's rotation is not constant: tides and internal friction cause the planet to lose momentum and slow down the rotation, leading to a quadratic difference between earth rotation and atomic time. In the next century we will need a leap second every year, often twice every year; and 2,500 years from now we will need a leap second every month.
On the other hand, if we stop plugging leap seconds into our time scale, noon on the clock will be midnight in the sky some 3,000 years from now"
Apparently it's only 3000 years:
"Leap seconds are not a viable long-term solution because the earth's rotation is not constant: tides and internal friction cause the planet to lose momentum and slow down the rotation, leading to a quadratic difference between earth rotation and atomic time. In the next century we will need a leap second every year, often twice every year; and 2,500 years from now we will need a leap second every month.
On the other hand, if we stop plugging leap seconds into our time scale, noon on the clock will be midnight in the sky some 3,000 years from now"
http://queue.acm.org/detail.cfm?id=1967009