Do all planets revolve the same way? What makes the earth spin in the direction it spins?

Answer 1

Revolve, as in orbiting the Sun? Yes, they all orbit the Sun in the same direction Earth does. Some comets and asteroids orbit backwards, and some (moreso comets than asteroids) orbit virtually perpendicular to the plane of Earth's orbit.

Rotate, as to spin on ones axis (the thing that causes day and night on Earth)? Earth rotates counter-clockwise, as seen from above Earth's north pole, the same direction it revolves around the Sun. But two planets (used to be 3, when Pluto was a planet) rotate clockwise - Venus and Uranus. Some might quibble about Uranus, as it spins on its side, but technically it rotates clockwise.

Why do they all revolve in the same direction, and most rotate in the same direction? Because of the way the solar system formed. It formed out of a nebula - a giant cloud of gas and dust in space. This cloud had a slight rotation to it. Gravity caused the dust and gas to come together, but since the nebula was spinning, it collapsed into a disk instead of a sphere. The center of the disk, that's where the Sun formed. The rest of the disk (now rotating quite nicely) is where the planets formed. So all the planets revolve in the same direction because that's the direction the original nebula was rotating.

Why do some planets now rotate backward? They got clobbered by one or more large asteroids while they were forming, which caused their rotation rate/direction to change. Earth got clobbered, too, at least once - that's how we got our Moon!

Answer 2

OK, here we go... Before the Sun and the solar system existed, this area of the Galaxy contained a huge cloud of interstellar gas and dust. A nearby massive star exploded as a supernova and shock waves passed through the cloud. As it passed through a couple of things happened. One effect was the could was enriched in heavy elements (remnants of the supernova) and the other was that the shock wave stirred the cloud. The cloud was not uniform in density. Some areas were thin and some denser. As the shock wave passed it compressed some of the denser areas and created currents and eddies. This is like taking your hand in a pool of water and pushing it along. Waves and eddies are created. From this motion large clumps of matter began to accumulate. Their mutual gravitational attraction caused these clumps to compact. But because of the currents, they began to swirl. The large clumps compacted faster to form stars faster. Other clumps, like the one that formed the solar system, took hundreds of millions of years to compact. Typically one of these giant gas clouds can create hundreds of stars in what are called clusters. So, the Sun and solar system, was just once clump of many. Its spin was created by the passing shock wave of a super nova. This is the origin of the somewhat circular orbit of the planets around the Sun. If any planet did not have that circular motion it would have more rapidly been pulled into the Sun by gravity. What we see as planets are those lucky ones who had the right direction of speed and the right distance from the Sun. The spin of the planets and the spin of their moons and the circular orbits of those moons all are related to the overall swirl and collapse of the initial clump. This is not speculation as astromers can see these stages of evolution in gas clouds in our own Galaxy. They have even see star formation from gas clouds in other galaxies. Also, you mentioned that the planets will go crashing into the Sun. Maybe Mercury, but not the others. And the Moon is not going to come crashing into the Earth. In fact it is getting a little more distant. It has to do with orbital dynamics.