Today is the vernal equinox and all over the world day and night are of nearly equal length, hence the word equinox meaning “equal night”.
There are two notable exceptions, though — the North and South poles, which, by a strange quirk of nature, receive 24 hours of daylight today. As the Sun’s rays pass through the Earth’s atmosphere, they are refracted and bent slightly, making the Sun appear just above the horizon and then to skim completely around the horizon for a full 24 hours. And at the North Pole, today’s sunrise also marks the end of six months of winter darkness, and it will now stay in daylight continuously for the next six months. At the South Pole, the opposite is true.
Another feature of the equinoxes is that the Sun passes exactly overhead at midday on the equator. The Sun also rises exactly in the east and sets exactly in the west across the world.
And the length of daylight is also changing very rapidly — in the UK the daylight will be roughly half an hour longer in a week’s time, which really makes it feel as if the seasons are turning.
But it is a myth that an uncooked egg can be balanced more easily on its end on the spring equinox than on any other day of the year. The gravitational forces of the Sun at the equinox are supposed to keep the egg upright, but this is not true. In any case, the Moon exerts a far greater gravitational pull on Earth, which works independently of the equinox.
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The legend of the balancing egg seems to come from a misunderstanding about an ancient Chinese custom. It was thought that eggs could be balanced more easily on “Li Chun”, the Chinese start of spring, which falls in February and is definitely not the vernal equinox. In 1945 an American journalist reported in Life magazine how eggs were balanced in China on the first day of spring, but when this story was picked up by a news agency, the Chinese first day of spring was mistaken for the equinox, and so the urban myth was born.