Ronn Blankenship wrote: > >For Earth: > >Winter Solstice (Northern Hemisphere): 21 Dec >Perihelion: 3 Jan >Summer Solstice (Northern Hemisphere): 21 Jun >Aphelion: 2 July > >+/- a day or so due to leap years and time zones. > But then you mask the most important information about these dates: our Gregorian Calendar was constructed so that the Winter Solstice is *always* close to 21 Dec [current error: 1 day in 4000 years - and there is a suggestion to make Y4000 a non-leap year, to reduce even more this error]. However, the day of aphelium and perihelium may vary; in fact, the first order approximation for this variation is about 1.5 days per century [if I did the calculations correctly :-)] Alberto Monteiro
