Oelm
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Theoretically, such an equation exists. For Earth, this equation consists of several factors. That is, it takes into account the ABSOLUTE rotation around the Sun, the absolute rotation around the center of the galaxy, and so on. As a result, we get an equation for the ACCELERATION VECTOR of the Earth at each moment in time (the trajectory equation itself doesn't say anything). For the Sun, it's the same, but its equation doesn't include the factor of movement around the Earth.
No. The equation of motion of bodies in the universe includes only gravity and the mass of the bodies (and possibly initial conditions). All other abstractions, such as the rotation of the Sun around the Earth, are unnecessary and are a product of the imagination. This is in classical mechanics. As for how things actually are, you should ask an expert, like Dirty_player, who at least positions himself as such.
Земля нуля.
Все в ней нулево и кукольно.
Все в ней нулево и кукольно.