With so much going on gravity-wise, it blows my mind that even with the solar system moving around the galaxy, everything stays so perfectly in place.
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gravity is the attraction between two masses. The larger the masses the larger the attraction. It also quarters when doubling the distance between the masses.
Now the sun is very big and heavy, the planets not so much.
The galaxy as a whole is also pretty heavy, but very very far away, especially the gravitational center. So the gravitational forces are pretty small because of the distance and mainly affect the heaviest body, the sun.
So the planets do experience the gravity of the galaxy, but it is so small in comparison to the sun’s gravity, that is not really noticeable.
The speeds don’t matter. Speed only exists relative to something else. As far as each planet is concerned on its own, it isn’t moving.
As far as the solar system is concerned, the planets orbit the sun and that’s all. The solar system does not ‘feel’ any motion because the only thing that is pushing on it pushes evenly on all of it.
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Same reason you can calmly walk to the bathroom of an airplane while both of you fly through the air at ~500 mph.
There can be some wiggle and jiggle in orbits and paths, just at the scale of the universe and the scale of human lifetimes, it’s not noticeable. Gravity drops off with inverse square law, so the biggest factors affecting Earth other than the moon and sun would be Jupiter and Saturn, but only over tens or hundreds of thousands of years.
Their orbits might actually not be stable over millions of years: see [this video I made about how Mars could collide with the Earth](https://www.youtube.com/watch?v=zRX3ixS1wMg)!
There are lots of ways planets could be arranged that wouldn’t be stable, and they could be affected by passing other stars too (though this is quite unlikely as the distances between stars are enormous and gravity gets weaker the further away they are), so perhaps the best explanation of why the Earth’s orbit is stable is that we’re here to see it. If it wasn’t, we might have crashed into another planet or the Sun by now, and we wouldn’t have evolved and invented Reddit.
Compared to the distance between the earth to the center of the galaxy, the distance between the earth and sun is nothing.
As far as the galaxy can tell, the sun, earth, other planets, and the entire solar system is just one object, super tiny, and super far away. And as far as the earth and sun can tell, the galaxy is just the stage where they interact with each other. The earth is so close to the sun compared to the size of the galaxy, that the main force it feels is from the pull of the sun. Any way the sun moved, the earth would follow, in orbit. The same thing is happening between the earth and the moon. Anyway the earth moved, the moon would follow, in orbit. The distances are just so much smaller that the gravitational force between the earth and moon are huge compared to the earth and sun. (Think, why aren’t humans pulled off the earth by the sun during the day? We’re just too far from it, and too small to feel the force)
So the pattern continues from the smallest things in space to the largest structures. Small orbits medium, orbits large, orbits huge, orbits gigantic. And each step only really feels the force of the next step up, because thats the closest thing thats also big enough to have a decent gravitational force on that object.
There is no difference between an object that is “at rest” (i.e. not moving) and an object that is moving at a constant speed of 100,000mph. If you were in a spaceship with no windows, be traveling at a constant speed with no acceleration, there would literally be no test you could perform to determine if you’re at rest or moving at a constant speed. That’s because motion and speed is all relative. There’s no absolute speed. Even though you may not realize it, whenever you talk about how fast something is moving, it’s always measured relative to something else (usually either yourself, or the Earth).
When it comes to the solar system, the planets’ orbits are mostly defined by the pull of the sun’s gravity. Our motion or non-motion relative to other stars and galaxies has absolutely no effect on the orbits of the planets in our solar system.
I think the reason that you intuitively think that our relative motion through the universe should cause an effect is because you’re used to that being the case on earth. If you tie a ball to a string and swing it around in a circular motion, you notice that the ball has various forces applied to it as a result of this motion. The string pulls on the ball, gravity continues to pull the ball down, air resistance resists the motion of the ball, etc. However, in space, these forces aren’t relevant, except gravity. And, gravity isn’t actually a force. Look up the Veritaseum video on YouTube about gravity not being a force.
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