Why are days and nights equal everywhere on 21st march and 23rd september?

The event known as equinox is eagerly awaited by space enthusiasts as it takes place twice a year on March 21 and September 23. Days and nights are equal at all places on earth on March 21 because on this day sun rays will fall in the vertical direction towards the equator or at the center position of the earth.

Explanation:

Nights and days are equal because on this dates we have spring equinox and autumn equinox that are happening only twice per year.

Explanation:

Of course, we need to have in mind that southern and northern hemisphere are having different seasons. So when it is winter in the northern hemisphere, there is summer in the southern, and vice versa.

Still, of course while on 21st of March on the northern hemisphere we have spring equinox, on the southern one we have autumn equinox.

It goes the same for 23rd September, only the seasons are different.

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