I did not say the sun was fixed. I said it was the dominant force of gravitational attraction in the solar system. And, like the other eight planets, the earth goes around it. That fact and the fact that the earth’s axis is tilted relative to the ecliptic plane (the plane of the earth’s motion around the sun) accounts for the seasons, and for why it’s winter in the northern hemisphere when it’s summer in the southern hemisphere. When the earth is on one side of the sun, the north pole’s maximum tilt toward the sun occurs on the first day of summer (i.e., summer begins in the northern hemisphere, winter begins in the southern hemisphere - the south pole’s maximum tilt away from the sun). On the other side of the sun (6 months later), it’s the opposite. The first day of spring and autumn occur when the north and south pole have no tilt toward the sun. But as you say, the solar system is part of a larger system, which is part of a larger system, etc. Engineers try to understand things by breaking them down into subsystems, systems, etc. If you model a subsystem correctly, you can take that understanding and plug it in to understanding the larger system, etc. Jesus said the truth sets us free. That simple statement is probably one of the most profound things ever said by anyone. It applies to moral and religious truth, certainly. But it also applies to natural truth. One measure of truth, is the freedom it obtains. If biologists discover some truth about biochemistry, and that truth is used successfully to fight disease, I think that illustrates what Jesus said. Likewise, if engineers use their understanding of Newtonian mechanics to navigate satellites around the solar system, that demonstrates the truth of their model. Is the truth complete? No. Only God knows the complete truth. But it is adequate to do what we want to do in our corner of the solar system.