OK, dumb question, since when did these 4 major events not become important

Winter Solstice  ie first day of Winte
Summer Solstice  ie first day of Summer
Vernal equinox  ie first day of Sprin
Autumnal equinox ie first day of Fal

How do I get these major events to appear on my calandar

For those who do not know here is a quick lesson

The Sun is at its lowest path in the sky on the Winter Solstice. After that day the Sun follows a higher and higher path through the sky each day until it is in the sky for exactly 12 hours. On the Spring Equinox the Sun rises exactly in the east travels through the sky for 12 hours and sets exactly in the west. On the Equinox this is the motion of the Sun through the sky for everyone on earth. Every place on earth experiences a 12 hours day twice a year on the Spring and Fall Equinox
After the Spring Equinox, the Sun still continues to follow a higher and higher path through the sky, with the days growing longer and longer, until it reaches it highest point in the sky on the Summer Solstice

The dates shift through the Gregorian calendar according to the insertion of leap years.

HELLO MICROSOFT THIS SHOULD BE STANDARD TO THE CALENDAR... SOME OF US STILL GIVE KNOW AND CARE ABOUT THESE EVENT