Do the spring and autumn equinoxes give us days and nights of the identical size? It is not so easy, says Abigail Beall on this month’s Stargazing column
17 March 2021
THIS Saturday (20 March) marks the vernal – or spring – equinox, when the solar crosses the celestial equator, sitting precisely between the hemispheres. It additionally marks the beginning of spring within the northern hemisphere and the start of autumn within the southern hemisphere.
You may need heard that day and evening are of equal size world wide on the equinox (therefore the title), however this isn’t strictly true. In an equinox, there are round 12 hours of daylight and 12 hours of evening, however most locations on Earth will obtain barely extra daylight (see desk).