This animation shows why leap years are necessary. Without them, December would eventually drift into summer.

Tech Insider
earth in space with swirling clouds green and brown continents overlaid with giant calendar illustration showing February 29
Leap Day is coming up and its purpose is to keep our seasons in check.

Norman Kuring/NASA/GSFC/Suomi NPP; bgblue; Business Insider

The 2023 spring equinox is here — here's what it is and how it works

Tech Insider
nasa apollo 11 earth africa 1969 AS11 36 5352HR
Earth is a like 7,917-mile-wide rotisserie chicken.

NASA/Flickr

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