The fall equinox marks the first day of autumn. When does fall officially begin in 2025? This visual guide will help get you ...

Fall begins in the Northern Hemisphere on Monday, Sept. 22, when Earth experiences equal day and night, known as the autumnal equinox.

Day and night will get equal time for a brief moment as the equinox arrives. The Earth will experience about the same amount of day and night on Monday when the autumnal equinox arrive.

Here's what happens as the direct rays of the sun slip south of the equator as the seasons change.

This year, the autumnal equinox in the Northern Hemisphere falls on Monday, Sept. 22. If you want to be extra specific and mark it on your calendar, mark it for 11:19 a.m. PT. The meaning of equinox ...

The moon and Venus will shine vividly alongside a bright star in the early morning in a celestial rendezvous that should be visible across the U.S.

The bottom half of the world, known as the Southern Hemisphere, is about to be treated to a partial solar eclipse that won't be visible in the US.