The day would shift half an hour in the next 600 years. That’s half as much as it shifts twice a year for DST, except it would happen gradually over a period of time roughly equal to the time between the fall of the Eastern Roman Empire and today.

I was sort of nodding to the people who claim they have a 25 hour sleep cycle. Once we are in space and using artificial light, you can choose the sleep cycle that suits you. But predicting things in 500 year is just Sci Fi I guess!

I'm reasonably sure that any assumptions about how our anatomy will look like in 500 years are more wrong than right.