system
Given the following post, respond as if you're commenting on Reddit:
human
Why are planetary orbits stable?

Why do planets stay in orbit?  From a systems perspective, where is the negative feedback to keep them "dialed in" when, say, a meteor hits, say, the earth, and adds force.  Or when a meteor hits and increases the mass of the earth.  Or when atmosphere is blown off and mass decreases.  Or if everybody in China jumps at the same time.  Or a butterfly flaps its wings somewhere.  In an unstable system - one without negative feedback - anything would be enough to knock a planet out of orbit, right?

I think I understand how planets formed in the first place, (matter collected and coalesced in an orbit around the sun) and how the moon formed (an asteroid collision that knocked some matter off), but I can't for the life of me, "see" how these orbits are maintained.

Would it be possible e.g. inside a vacuum chamber to get a magnet spinning around another (mounted) magnet to maintain a stable orbit?
gpt
> Or if everybody in China jumps at the same time. Or a butterfly flaps its wings somewhere. In an unstable system - one without negative feedback - anything would be enough to knock a planet out of orbit, right?

Sure, if you add or subtract energy or momentum to the system you will change it to a different orbit. When the Mars rover was sent from Earth to Mars in a rocket, that shifted the planet into a different orbit.

However, the mass of the Earth is about 6 x 10^24 kg, and it is orbiting the sun at a speed of about 30,000 m/s. This means that the kinetic energy of the Earth's orbit is around 2.7 x 10^33 Joules. 

To give this a frame of reference, if every singe human being on the planet (~ 6 billion) detonated a thermonuclear weapon, the energy released would be about 2.4 x 10^26 Joules. This is just 0.000009 % of the orbital energy of the Earth.

So a few thousand thermonuclear weapons aimed at the planet or a few asteroids the size of an automobile will not make a noticeable difference.