For people in the Northern Hemisphere, Monday, September 22, is the autumnal equinox. That is one of the two times of the year when the sun shines directly on Earth’s equator. It marks a change of seasons. Summer turns to fall in the Northern Hemisphere. Winter becomes spring in the Southern Hemisphere. Most people around the world won’t notice an immediate change. But for the few living at the top or bottom of the world, the difference will be night and day — literally. Because of the Earth’s tilt as it revolves around the sun, for the next six months, the Southern Hemisphere will be closer to the sun. Countries there will get more daylight in 24 hours, even as the Northern hemisphere’s daylight decreases. And the North Pole? It won’t see the sun again until spring. "This darkness is complete, so you have to sort of live with that and you have to see the beauty in that. And to me, that's not hard at all," Fålun Strøm, a climatologist who lives near the North Pole, told NPR. "I kind of feel even more immersed by nature when I walk out into the darkness." Those stationed at the South Pole’s Amundsen-Scott South Pole Station will experience the reverse. Though the sun’s been flirting with the region, causing the sky to glow, the researchers stationed at the South Pole may see on Monday their first glimpse of full daylight since March. Reflect: How do you mark the passage of seasons? When summer turns to fall, does anything “feel different” to you?