3 ms·
The sidereal year is what we're talking about here, the time it takes the earth to orbit the sun and come back to the same position. What's changing isn't that,
by TimSchumann 7y ago
The sidereal year is what we're talking about here, the time it takes the earth to orbit the sun and come back to the same position. What's changing isn't that, it's the sidereal day.
Earth spins slower > Moon Speeds Up
Less Rotations per Orbit > More Hours per Day
Number of days is changing because the day is going from 23.X hours to 24.X hours due to the Earth rotating slower. Hence, same length year if you measure it in absolute time, just less days in relative time.
- jbay808 7y agoAssuming that revolution means sidereal year, this discussion thread is speculating about how minute the changes in the sidereal year would be, and in what direction they would have been. I don't think there's confusion about the fact that the orders of magnitude larger change as discussed in the article is in the sidereal day, except perhaps for GGGGP's comment that started the thread. >>>>> Wasn't the Earth's revolution on a different period back then too? >>>> There is no force comparable to lunar tidal forces affecting the period of revolution >>> But there are... The earth orbiting causes tiny tides on the sun [...] Over time, tidal drag will tend to make years longer. >> Wouldn't tidal drag make years shorter? > What's changing isn't that, it's the sidereal day.