Is it possible that in 13,000 years it will be summer in December in the northern hemisphere? Or do we artificially change the definition of the length of the year to ensure this never happens?
DELAY EVERY NEW YEAR by
The Great Year of about 26000 years is the period for this
retrograde time motion that is attributed to the precession motion of
the Earth's tilt ( polar ) axis. In half of this period, we go back in time,
from solstice to summer and vice versa.
To neutralize this effect for our future generations,
we can DELAY EVERY NEW YEAR# by
#20 min 14 sec /year.