Most people have had the idea that Earth spins on its axis drilled into their heads over the course of several years of science education. Do you recall your teachers mentioning the direction in which Earth spins?
There is, in fact, no single right answer; rather, it varies depending on where you are in relation to the Earth. From above, Earth’s rotation appears anticlockwise if you stare down at the North Pole. As seen from below, the rotation is clockwise if you’re at the South Pole and looking up at the North Pole.
Because Earth is rotating from west to east, it makes sense that the sun “rises” in the east and “sets” in the west. Think seeing yourself as the sun, looking down on Earth right as the day breaks in North America. Since the Earth rotates anticlockwise, the East Coast receives sunshine after the New York area has already risen from its slumber.
Sunlight gradually spreads across more of North America as Earth continues to rotate eastward. If we gaze to the east, we can see the sun coming up and entering the area where people live on the ground.
Sunset is the same way. As Earth continues to rotate to the east, the East Coast finally moves out of the sun’s arc and into the shadows. While the sun has set over the Atlantic, it is still up in the west, so those on the East Coast may watch the sun set over the Pacific.
The Earth Spins Anticlockwise, But Why is that?
It’s not as obvious why Earth spins in a anticlockwise direction (from west to east). The stuff in our solar system, guided in part by gravity, reoriented itself into a star and a group of planets when a cloud of dust and gas collapsed, probably as a result of the explosion of a nearby star (plus moons, asteroids, and so forth).
The star and its surroundings revolve as a byproduct of star formation, but the direction in which they rotate depends on factors at play during the collapse of the cloud.
The final angular momentum and spin orientation of newborn stars are affected by “factors like as turbulence induced by supernova shock waves and magnetic effects that occur as portions of the cloud start collapsing into stars,” Alison Klesman wrote in Astronomy.
Our solar system’s final spin orientation turned out to be prograde, or anticlockwise. That’s the direction in which the Earth, Sun, and other planets all spin. While Uranus turns on its side, Venus spins in a clockwise direction.
There is a school of thought among scientists that holds that their spin orientation formerly matched ours but was thrown off by some kind of disruptive event, be it a single large collision or a series of smaller ones. Though the truth of the matter remains unclear.