Today is the spring (or vernal) equinox in the northern hemisphere. This is one of the four transitions — two equinoxes and two solstices — from one season to another: from winter to spring, to summer, to fall (aka autumn), and back to winter.
The reason that earth has seasons is that it is tilted on its axis at an angle of approximately 23.44 degrees (called its obliquity) due to a colossal impact early in its history around 4.5 billion years ago. The hypothesis is that a protoplanet collided with the early earth. This collision caused it to tilt off its perpendicular orientation relative to its orbital plane around the Sun.
During an equinox, the sun rises exactly in the east and sets exactly in the west, and both hemispheres receive almost equal sunlight. The sun is positioned directly above earth’s equator, and the earth is tilted neither toward the sun nor away from it, resulting in nearly equal lengths of day and night across the globe. Continue reading “Equinoxe”
Atanu Dey : Life is a Random Draw 