Using a 64 bit unsigned integer with nanosecond resolution gives us 585 years (2^64/1e9/60/60/24/365) after 1970 to come up with a new format. This, combined wi

Using a 64 bit unsigned integer with nanosecond resolution gives us 585 years (2^64/1e9/60/60/24/365) after 1970 to come up with a new format. This, combined with using some other format to describe dates before 1970, seems like a sensible solution to me.