I understand the Earth is spinning around 1040 MPH, my question is why ? I mean what started us spinning and why haven’t we stopped yet ? are we slowing down ?I’ve been told that 5 planets spin the same way, and three spin the the other and Uranus spins on it’s side ??? Just curious… 
Earth’s spin is slowing down, but very slowly.
Planets are formed by the collecting and hardening of general space matter. I believe the term for this process is accretion. Imagine a whole vat of general space matter - the matter is almost certainly going to have currents going on in it. As the matter hardens, the currents are going to start cancelling one another out. For example, a chunk of ice going west is going to run into a chunk of mud going east, and they’ll stick together not going much at all.
So far so good. Earth became a clump of matter, with its attendant gravitational effects, and started gathering other matter. The thing is, the momentum from the original currents is still there, unless it’s been cancelled out. So, all the momentum gets added up, and the “uncancelled” remainder is Earth’s spin. Since Earth is mostly solid, it’s all got to spin the same way. I mean, if a big chunk of rock originally wanted to spin north to south instead of west to east, too bad, it’s got to play along or get off. The water is an exception, since it can slosh around, but mostly it plays along too.
As to the question of why the other planets spin, it’s pretty much the same thing. Since we all go around the sun in the same direction, we know that the original grand total of all the matter in the solar system was in that direction. The matter collected into little gravity puddles, like globs of oil on the surface of water. Most of these little puddles are probably going to have “momentum subtotals” that are the same direction. Not all of them have to, since a bunch of counterclockwise vortices (hurricanes, gobs of matter, etc.) will tend to create little clockwize vortices between them.
Basically, a lot of the process is random, and some of it isn’t. Earth cooled and shrank, and, as the odds would predict, the momentums of all the particles didn’t cancel perfectly. This left a spin.
That could require a pretty long answer …
There is a quantity called “angular momentum” that is important whenever anything is rotating. The angular momentum of a small object is the mass of the object times the distance from the obect to the center of rotation times the square of the “angular velocity”. The angular velocity is the change in the angle of the line from the center of rotation to the object divided by the time over which that change took place; it can be measured in degrees per second but it usually appears in radians per second in real calculations. For large objects, we conceptually break them down into small objects and add up the contributions of all the small objects.
The angular momentum of any isolated system is a constant except for processes which dissipate energy as heat. The classic example of this is a spinning figure skater. As she/he pulls her/his arms in closer to her/his body, the speed of rotation increases. The mass stays the same, the average distance to the center of rotation gets smaller, so the angular velocity has to increase to keep angular momentum constant.
It’s reasonable to consider the entire Solar system as an isolated system with constant angular momentum. Current theories (which are likely to be true or close to true) have it that the Solar system condensed from a cloud of matter that originally occupied a volume of space much larger than the current Solar system (on the order of one billion times larger). The motion of atoms and particles and chumks within this cloud was essentially random, and the probability that such random motion had zero angular momentum is essentially zero. The condensation of the volume of the Solar system by that factor of one billion is exactly the same as the case of the skater; the mass stayed the same, the distance from the center of rotation got smaller, so the angular velocity got faster.
This cloud condensed by gravitational attraction and sticky collisions into the current Solar system. Some of the original angular momentum was lost as heat, but most of it is still around. The angular momentum is now made up by bodies rotating (orbiting) around the Sun, bodies rotating (orbiting) around other bodies, and bodies rotating. Such as the rotation of the Earth. However, in collisions, some bodies wound up rotating “opposite to the common direction” or at some angle to the common direction. This is OK; the “negative” angular momentum of those bodies is made up for by increased “positive” angular momentum of other bodies, and the total angular momentum remains constant.
The angular velocity of the Earth is slowly decreasing. Tidal friction (which is a complex subject in itself) causes this. But angular momentum is conserved; the Moon is slowly moving away from the Earth by just the correct amount to keep the overall angular momentum constant.
“we know that the original grand total of all the matter in the solar system was in that direction.”
I meant to say, the grand total of the momentum of all the matter…
“The matter collected into little gravity puddles, like globs of oil on the surface of water. Most of these little puddles…”
The little globs of oil are supposed to be young planets, by the way.
I believe energy is also being carried away from the earth in the form of gravitational waves (kind of like a cork bobbing in water). Eventually this will cause the earth to spiral into the sun.
However, if I remember my reading correctly the amount of energy leaving the earth in this fashion is about enough to run a toaster. Given the size of the earth this doesn’t amount to much. The solar system will be LONG dead before the earth stops moving or spirals into the sun.
Currant theory with Uranus IIRC is that it probably had spin perpendicular to the solar system, like the rest of the planets, but was hit by something that disrupted its motion.
Given the size and mass of Uranus it must have been quite a strike.
Not to disagree with all the stuff about angular momentum (because it’s true), but it might be a bit easier to think about by analogy. It’s a similar reason to why the water forms a little whirlpool when you pull the plug in the bathtub. There’s some motion in the tub or in the protoplanetary cloud, and that motion gets concentrated into the whirlpool or planet when it all comes together.
Angular momentum is just the techie word for the type of motion we’re interested in here.
That’s a good one, as long as your audience knows that Coriolis force is insignificant in their bathtub …
Simply, intertia from when the planets formed. Kinda like when people ask why they don’t fall off the planet if its going so fast, well you were born onto a spinning planet and you’re full of the very same inertia.
More related trivia is that the closer the planet is to the sun, the faster it moves around the sun. Also, the slowing of the earth’s spin is connected to the moon slowing moving farther away, so that eventually total solar eclipses will no longer exist - the apparent lunar disk will be smaller than the apparent solar disc, so only annular eclipses are possible.
There’s even fossil evidence for the slowing of the earth. Fossil coral show evidence of daily and yearly growth cycles, so you can count the number of days in a year. Several hundred million years ago, there were 400+ days in a year.