Well the Earth's orbit is an ellipse, so there are times of the year where we are closer to the sun (January is when we are at perihelion).

We could either change our eccentricity in order to shorten our year to exactly 364 days, or we could keep our eccentricity constant and change our perihelion and aphelion.

I'm too lazy to do the math to figure out whether the change via either approach would be less than the difference we already experience due to our current orbital eccentricity.

Would love to know, if anybody feels like doing the algebra.

We could potentially do it over the span of millions of years. Not without risk though. And generally we would want to move further from the sun when it reaches a later stage in its life and starts to expand. https://en.m.wikipedia.org/wiki/Moving_Earth

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?

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...

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

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.

All in the name of a more simple calendar