Where do planets get energy to revolve around the?

Answer 1

Another question for which we cannot be certain of the answer.

However, we can be fairly sure that some of what we call "fundamental laws of nature" will act predictably. One of these is the "law of conservation of angular momentum". Another is the law of gravity.

The matter that made up our solar system was, five billion years ago, an enormous cloud of dust and gas. Some of the gas had been floating around in space since the Big Bang, 9 billion years before, but a lot of it had been inside one or more giant stars that had gone nova and exploded, or gone supernova and REALLY exploded. And some modern scientists believe that even the energy of a supernova would have been insufficient to create really heavy elements like gold and uranium; that these elements could only be formed in the collisions of neutron stars crashing into each other. But we know that there is, in megaton lots, gold and uranium on and in the Earth.....

Anyway, the gas and dust blown into space by the explosions and collisions gathered in space, and the universal attraction of gravity started to pull it all in together. But the gas and dust atoms were all moving, and not all in the same direction; we believe that there was, overall, some net "spin" to the gas cloud. As gravity pulled it all in together, the collection of the angular momentum, or "spin energy", of the proto-solar system was all maintained - but to keep the same angular momentum in a smaller area, the amount of spin must increase.

So, the spinning of the Sun, and the energy of the planets in their orbits, and the spinning of each of the planets, was all contained in the spin of the original dust cloud. This would explain, for example, why all the planets (and almost all of the asteroids) all orbit the Sun going pretty much the same way, and why the rotations of all but two of the planets is in the same direction. (Venus rotates "backwards", but VERY slowly, while the spin of Uranus is"sideways" compared to the ecliptic.)