Spring twilight at the North Pole begins a few weeks before the vernal or spring equinox in March when the Sun rises above the horizon again.įurthermore, the September equinox in the Northern hemisphere also marks the beginning of a period bringing late sunrises and earlier sunsets. That's because Earth's axis is tilted with respect to the Sun-Earth plane. While on these days, the Sun shines almost equally on the Northern and Southern hemispheres, the rest of the year, it shines unevenly over the two regions. The phenomenon-the spring and fall equinoxes-happens twice in Earth's year-long trip around the Sun. The astronomical event will also be witnessed in India on Thursday (September 23), as the country is also part of the northern hemisphere. On Wednesday, the Sun will be exactly above Earth's equator, moving from north to south, making day and night nearly equal in length-about 12 hours-throughout the world, said the US space agency NASA in a blog post. The astronomical event is caused by Earth's tilt on its axis and its motion about the orbit around the Sun. September or the Fall equinox, occurring on Wednesday, marks the astronomical autumn season for people living in the Northern Hemisphere and astronomical spring season for those in the Southern Hemisphere.Įquinox comes from the Latin words equi, which means "equal" and nox, which means "night".
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