So planets orbit stars. Stars orbit the galaxy. The galaxy forms super clusters with other galaxies moving through space.
What do galaxies orbit and when they form super clusters, what do they orbit/what determines direction/speed/etc of their movement?
From my understanding Andromeda and the milky way will one day collide in a billion years. So we’re obviously pulling each other together. Whats then pulling us along?
In: Physics
The orbits of the galaxies within a supercluster is guided by the center of gravity of the galaxies in the cluster. Basically the mass of the galaxies hold the cluster together and they move around the gravitation center of the overall mass. In the solar system that point is inside the sun, but if the solar system had two stars of equal mass orbiting each other the center of gravity would be a point in space half way between the two stars. Same concept, just with a lot of galaxies instead of two stars.
The motion of superclusters follows the same concept, except its based on the center of gravity of all the other superclusters/galaxies/what have you.
Overall there isn’t anything really “pulling” on us. Newton’s Laws of Motion explain this. If an object is moving in a direction at a velocity, it will continue to do so forever unless acted on by a net force. And every action has an equal, but opposite reaction. Any object that is pulling us towards it is also being pulled towards us by us. One will have a larger amount of motion due to differences in mass. The same force is applied, but the smaller mass will be accelerated faster by the same force.
If you say step off of a platform and fall a little to the ground, the entire time you are falling to the earth, the earth is also falling towards you. The difference in mass means that you travel almost the complete distance of separation, but the earth also moves the tiniest little bit (I’m talking sub-atomic distances).
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