21 march -Equinox

 Spring begins in the Northern Hemisphere at the equinox on March 20, 2021, at 09:37 UTC. At the same moment, the Southern Hemisphere enters the autumn season.

        No matter where you are on Earth, the equinox brings us a number of seasonal effects, which many nature enthusiasts notice.

    Equal day and night? At the equinox, Earth’s two hemispheres are receiving the sun’s rays equally. Night and day are often said to be equal in length. In fact, the word equinox comes from the Latin aequus (equal) and nox (night). For our ancestors, whose timekeeping was less precise than ours, day and night likely did seem equal. But we today know it’s not exactly so. 

Fastest sunsets at the equinoxes. The fastest sunsets and sunrises of the year happen at the equinoxes. We’re talking here about the length of time it takes for the sun to sink below the horizon. 

Sun rises due east and sets due west? Here’s another equinox phenomenon. You might hear that the sun rises due east and sets due west at the equinox. True? Yes. It’s the case no matter where you live on Earth. At the equinoxes, the sun appears overhead at noon as seen from Earth’s equator, as the illustration below shows. This illustration shows the sun’s location on the celestial equator, every hour, on the day of the equinox. No matter where you are on Earth – except at the Earth’s North and South Poles – you have a due east and due west point on your horizon. That point marks the intersection of your horizon with the celestial equator – the imaginary line above the true equator of the Earth. That’s why the sun pretty much rises due east and sets due west for all of us. The sun is on the celestial equator, and the celestial equator intersects all of our horizons at points due east and due west. 

Munteanu Roxana, Cuza Vodă High School Huși-Romania