Autumnal equinox
Autumn has officially begun! In the Northern Hemisphere, the autumnal equinox falls on September 23 this year, marking the beginning of autumn. Today is one of the two moments in the year when day and night are equal in length, thanks to the sun's location exactly above the equator. In the Southern Hemisphere, today marks the vernal equinox and they are heading into spring.
Camouflaged in autumn colors, the cottonwood tree in today's image might be playing peek-a-boo among the red sandstones of Coyote Gulch in southern Utah. Here in the Glen Canyon National Recreation Area, the canyon is painted orange by oxidizing water and other fluids, as well as iron-filled minerals.