Perihelion day, when the earth is closest to the sun. ‘Peri’ means near and ‘helion’ stems from the Greek word helios for sun
The earth’s orbit is elliptical which allows it to have a moment in the year where it is nearest to the sun (perihelion) and furthest away (aphelion).
The Perihelion always falls at the end of the tide of Yule around 14 days after the winter solstice each year between 1st-6th Jan. Yes ironically in the northern hemisphere when it is cold and with reduced daylight hours our earth is closest to the sun. That means on this day…if the skies are clear, the sun will appear at it’s largest, and then dwindle in size for the rest of the year (in the northern hemisphere).

This tide was deeply revered in ancient times…but it got co-opted by Christianity in the form of the celebration of the day of Ephiphany. You see the revealing of the baby Jesus to the 3 Kings on 6th Jan, is very much to do with the earths’ alignement with the perihelion of the sun ~ the revealing of the son/sun.
The sun is the most important star in our solar system, without it most life on planet earth ceases to exist, and ‘alas we have forgotten to celebrate and connect with it on this day when the earth is closest to it.