Question

Why does the planets revolve only in one direction ? why not the other way???

PROPER ANSWER PLS

Answer 1

Venus is a weird planet, at least in terms of its rotations! First of all Venus rotates extremely slowly around its axis, so slowly that one day on Venus (243 days) is longer than a year (227 days) on Venus. A possible theory of planets rotating from west to east is that during the formation of the planets the proto-planetary disk itself was rotating from west to east which gave the initial rotation direction. For Venus it can change the direction during the course of time.

Now Venus’s axis is tilted at 177∘177∘ and that made scientists to think about two possibilities.

Usual theory is that somewhere in the past, the core-mantle friction in Venus (it’s a pretty dense planet) along with tidal forces caused it to flip its axis by 180∘180∘. ReferenceIt can also happen due to several small collisions with heavenly bodies (which also explain Uranus’s tilt of 98∘98∘), or even one strong collisionwith a large massive body.

However, a vastly discussed work published in Nature suggested that a highly dense planet like Venus with similar environments can evolve into only one of four stable rotation states, independent of the initial conditions of different models.

Whatever the case is, it’s still under scientific study and hopefully studying a bit weird planets like Venus will help a lot to discover the nature of other extrasolar planets.

Cheers !

P.S: The sun rotates in the same direction about the axis just like any other planets (ex: Earth). So Venus’s rotation is indeed unusual!

Answer 2

The short answer is because of the conservation of angular momentum.

The long answer: Back before our solar system formed, all the matter it is comprised of was spread out in a cloud of disorganized gases and other matter. Over time, gravity would make that matter come together. The disorganized nature of the cloud in addition to forces from other nearby celestial bodies and/or local gravitational differences means it won't coalesce evenly. A natural spin will develop as the matter condenses. That spin force is conserved unless a large enough outside force affects it.

This same angular momentum also explains the rotational spin of the planets. In our own solar system, there are two exceptions. Venus and Uranus. It's thought that those two planets suffered a large impact at some point that imposed enough force to overcome the angular momentum, changing their rotations.