The first day of fall. Autumnal equinox. Whatever you want to call it, we're starting a new season today. You might even say we're turning over a new leaf.
The autumnal equinox ushers in the change from summer to fall. You've no doubt noticed the shift of late. Dawn arrives later, making it harder to get out of bed in the morning. Night falls much more quickly.
"The days are getting shorter, and day and night are approximately equal in length," explains the EarthSky website.
The Earth orbits on its axis at a tilt. "We have an equinox twice a year -- spring and fall -- when the tilt of the Earth's axis and Earth's orbit around the sun combine in such a way that the axis is inclined neither away from nor toward the sun," the online science site says.
The result is that the sun shines directly on the equator, creating a nearly equal amount of day and night.
Science aside, the autumnal equinox marks a symbolic shift for many of us.
Summer is in the rear-view mirror. There's a chill in the air. And it's time to start thinking about firewood, mittens, apple cider and Halloween costumes.