![]() ![]() This imaginary sphere is called the Celestial Sphere. For 2021, the autumnal equinox occurs on the 20th March 2021 at 5:37pm, and the vernal equinox occurs on the 23rd September 2021 at 3:20am.īy the way, the Celestial Equator is just a projection of Earth’s equator onto the imaginary sphere that we picture surrounding our planet when we look up at the night sky. ![]() On the dates of the equinox, the Sun is exactly above the Earth’s equator, causing the equal length of night and day. ![]() The autumnal equinox occurs around March 21, and the vernal equinox occurs around September 23 each year. These dates are known as equinoxes, and there are two a year. This means there has to be a ‘tipping point’ where hours of daylight are just about the same as the hours of night. Hours of daylight are greater in summer and less in winter. This happens on March 19, 20, or 21 every year. This axial discrepancy leads to changes in the amount of daylight any given place on the Earth receives. noun The moment when the sun crosses the celestial equator while heading northward, occurring on March 19-21. The March equinox is the moment the Sun crosses the celestial equator an imaginary line in the sky above Earth’s equator from south to north. For example the Southern Hemisphere is angled towards the Sun during summer and away from it in winter. Our Earth is quite laid back, about 23.5 degrees! The axis of rotation of our Earth is roughly 23.5 degrees, meaning that as the Earth orbits the Sun, the angle a point on the surface makes with the Sun varies. The Earth’s axis isn’t tilted toward the Sun one way or the other and the hours of night and day are almost equal in length. This is when the centre of our Sun is on exactly the same plane as Earth’s equator. Equinoxes happen twice a year when our Sun crosses Earth’s Celestial Equator. ![]()
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