[PullJosh]

Or, if that’s too hard, leave the orbit the same but slow the spin down a little so each day is longer. A 0.35% decrease in spin speed seems fine right?

[ninkendo]

According to Wikipedia [0], 70 million years ago the earth rotated about 7 more times per year than it did today, meaning we just need to wait about another 10 million years and it'll happen on its own.

[0] https://en.wikipedia.org/wiki/ΔT_(timekeeping)#Geological_ev...

[bhandziuk]

If we use enough tidal energy we can certainly accomplish this!

[didgetmaster]

I remember doing a physics problem way back in high school where the teacher asked how long it would take to slow the Earth down 1 m/s if everyone on the planet started walking in unison westward and never stopped. The population was several hundred million less then than it is today, but I think the answer was still measured in centuries.