“Imperfection clings to a person, and if they wait till they are brushed off entirely, they would spin for ever on their axis, advancing nowhere.” –Thomas Carlyle
When you take a look up at the sky, the two most prominent objects are the Sun and the Moon.
And every day, like clockwork, they rise in the East and set in the West.
Because the Earth rotates on its North-South axis! Not only does it rotate, but it rotates from West to East, and that’s why we see everything rise in the East and set in the West over the course of a day or night.
It gets better, though. If you rose up, above the Earth’s North Pole, and looked down at the Earth as it revolved around the Sun, not only would the Earth spin counterclockwise, it would also orbit the Sun counterclockwise!
So you might ask what other objects in the Solar System do? We can start with the Moon, of course.
Just like you might expect, the Moon both orbits counterclockwise around Earth and rotates counterclockwise on its axis, so that the same side of it always faces us!
Fine, fine, you say. But what about the other planets? Isn’t there some variety there?
Not a chance. Not in the least, in fact!
Not only do all of the rocky planets revolve counterclockwise around the Sun, and not only do all of the gas giant planets revolve counterclockwise around the Sun, but something like 99% of the known asteroids, kuiper belt objects, and comets also revolve counterclockwise around the Sun!
Stars — all of them, as far as we know — form when clouds of gas collapse. Since one direction will be shorter, that will collapse first, and so we’ll get a disc. (Or, in our “complicated scientific jargon,” a pancake. Yes, seriously, you say pancake to an astrophysicist and they’ll know you’re talking about this process.)
But this pancake isn’t just going to sit there. In general, there will be an overall, bulk, rotational motion, due to the law of conservation of angular momentum.
So not only should the planets all revolve in the same direction, but if this idea is correct, the Sun should rotate counterclockwise, too!
And not only does it rotate counterclockwise, we can measure that rotation by following sunspots!
But you might decide to look at the individual planets, and see if they not only revolve counterclockwise about the Sun, but if they also rotate counterclockwise about their own axes, tilted or not. The results may surprise you.
While Mercury, Earth, Mars, Jupiter, Saturn, and Neptune all rotate counterclockwise, at tilts varying from less than a degree up to substantial, significant tilts, two planets stand out as weirdos.
Venus, rotating almost perfectly backwards, and Uranus, rotating on its side, are the unexplained bizarre children of our Solar System.
Unlike some Moons (like Neptune’s Triton) that go backwards, we can’t blame Venus and Uranus on gravitational capture. There are ideas out there, such as big collisions in the young Solar System, but there is currently no compelling evidence that favors any one theory over the other.
So almost everything in the Solar System revolves and rotates counterclockwise (from the North), but Venus? Uranus? We just don’t get it, at least, not yet. Even in something as well-studied as our Solar System, we still have plenty of unexplained mysteries.