The laws of motion of Isaac Newton (1643-1727), presented in his Principia, are taught all over the world in high-school physics classes. Law 1: Every body perseveres in its state of being at rest or of moving uniformly straight forward, except insofar as it is compelled to change its state by forces impressed.
This speed of gravity thing is such a noodle. Years ago I had someone walk me through the General Relativity explanation, he claimed we were assuming that the distortions in spacetime were propagating at the speed of light. When he got to the end though, it was "as if" the Sun n& Earth were feeling each other's instantaneous positions, not the 8 minute lagged positions. I have no idea if others would agree with that presentation. But it kind of contributed to me not wanting to pursue GR.
This speed of gravity thing is such a noodle. Years ago I had someone walk me through the General Relativity explanation, he claimed we were assuming that the distortions in spacetime were propagating at the speed of light. When he got to the end though, it was "as if" the Sun n& Earth were feeling each other's instantaneous positions, not the 8 minute lagged positions. I have no idea if others would agree with that presentation. But it kind of contributed to me not wanting to pursue GR.
Relativity is like Buddhism. The teachers are on their way from poverty to wealth, while the students are travelling in the other direction.