Markus6 said:
i.e. You can't prove the Earth isn't stationary.
Looks like for parallax you need to stationary points. Hold on, special relativity says you can never prove a point is stationary...
Of course you can't "prove" anything. I mean, you could go with the extreme conspiracy theories and say that we all live in the matrix and nothing is real... but assuming that our observations are accurate (otherwise who cares about ANY theory based on our observations) we can say that the universe makes no sense if the Earth is stationary.
Yes, for parallax, you need two stationary points. Now as the Earth appears to revolve around the sun, we see distant stars moving exactly as if they are stationary points a certain distance away. Have you considered what a complex and totally unexplainable motion these stars would have to have in order to SIMULATE parallax???
Not only would they have to be moving around the earth every day at the same speed as the sun, but they would have to move back and forth with respect to each other in exactly the interval you'd expect in the parallax effect. Now you've got stars revolving wildly around the Earth and slowly oscillating back and forth...
It's the same set of hoops that people jumped through to justify a geocentric solar system long ago. Yes, you COULD model the entire system as planets revolving around the Earth -- and also turning on tiny little rings to produce retrograde motion (look it up if you haven't heard of it). But gravity and a heliocentric solar system explain it with the added benefit of using a known force, not a complex set of circles within circles.
We've used our understanding of gravity to predict and direct satellites and probes to distant planets and beyond the solar system. Our same understanding of gravity explains a heliocentric solar system. If gravity were not the prime force in the solar system and the Earth were stationary, you would NOT be able to direct satellites and probes as we do.
Or... perhaps we live in the matrix, and nothing we see or observe is accurate. But if so, who cares? Our observations are used every day in GPS, satellite observation of the Earth and missile launches throughout the world. Perhaps we live in the matrix, but if so, we're describing the rules of the matrix, and now that we've observed those rules, a stationary Earth makes no sense.
As a frame of reference, yes, we can assume a stationary Earth. But it really does make no sense to have the sun, the planets, the stars etc... revolving around a central Earth.