– Stonehenge (United Kingdom): Many mysteries about these giant slabs remain, but we do know they are aligned to mark the yearly passage of the sun. Long before the age of clocks, satellites and modern technology, our ancient ancestors knew a lot about the movement of the sun across the sky – enough to build massive monuments and temples that, among other purposes, served as giant calendars to mark the seasons. Since the summer solstice in June, days have been progressively becoming shorter in the Northern Hemisphere and the nights longer for the past three months. (That’s why it stays light for so long each day during the summer in places such as Scandinavia.) Those are the solstices, and they have the most extreme differences between day and night, especially near the poles. The effect is at its maximum in late June and late December. This discrepancy in sunlight is what triggers the seasons. That positions one hemisphere of the planet to get more sunlight than the other for half of the year’s orbit around the sun. However, the axis tilts at 23.5 degrees, as NASA explains. It’s called the axis, and this rotation is what gives us day and night. The Earth rotates along an imaginary line that runs from North Pole to South Pole. Here’s a handy online tool to convert UTC to your local time. (The UTC stands for Coordinated Universal Time.) There’s actually a precise time for it: 1:54 UTC. In 2018, it falls on Saturday, September 22. Here are the answers to some of your fall equinox questions:įrom our CNN Fast Facts file: The term equinox comes from the Latin word equinoxium, meaning “equality between day and night.” More on that farther down in the article. There’s a good explanation (SCIENCE!) for why you don’t get precisely 12 hours of daylight on the equinox. Well, there’s just one rub – it isn’t as perfectly “equal” as you may have thought. They have long, dark winters and summers where night barely intrudes.īut during the equinox, everyone from pole to pole gets to enjoy a 12/12 split of day and night. People close to the poles, in destinations such as Alaska, go through wild swings in the day/night ratio each year. For people south of the equator, this equinox actually signals the coming of spring.įolks right along the equator have roughly 12-hour days and 12-hour nights all year long, so they won’t really notice a thing on September 22. If you reside in the Northern Hemisphere, you know it as the fall equinox (or autumnal equinox). On Saturday, we enter our second equinox of 2018. Twice a year, everyone on Earth is seemingly on equal footing – at least when it comes to the distribution of daytime and nighttime.
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