Answer: Galileo was able to observe that not every moving body circled the Earth
Explanation:
Galileo noticed with the help of a telescope (which was invented earlier) that the moons of the Jupiter were orbiting Jupiter. By this analogy, he concluded that the planets orbit the sun, which is not a relevant scientific proof but a hypothesis.
He faced the problem because he could not perceive that the planets were orbiting the sun similarly. So this part of the theory could not be proved in any way.
