How did Galileo discover that the earth moves around the sun?

Answer 1

He had two major pieces of evidence: Venus going through phases (like the moon), and Jupiter having moons. He basically stated that Venus must revolve around the Sun if it had phases like the moon, and if Jupiter has things revolving around it then it is proof that not everything revolves around the earth. Beyond that he had no evidence, and it would not be until Tycho and Kepler that absolute proof would exist.

(Tycho's data allowed Kepler to determine the orbits with incredible precision, leading to the understanding that orbits are elliptical.) Actually, until Kepler I think the geocentric Ptolymaic epicycle system gave better results for determining the position and rise / fall of the planets in the sky - one of the reasons people were so slow to change their minds about geocentrism at first.

Between the time of Kepler and Galileo all sorts of patterns were tried before heliocentrism was accepted, some of which had several planets circling the earth and the rest circling the sun. However, by the time of Kepler most were certain that the earth (and the rest of the planets) circled the sun - they just were not sure why the timing of their movements in the sky and so forth could not be accurately understood except in the epicycle system of geocentrism.

Answer 2

Galileo was the one of the first persons to observe sunspots, and following them day by day, he was aware that they seemed to move across the sun's surface. His logical extrapolation was that the sun was rotating.

Answer 3

Amongst many other things, Galileo observed Venus in all four of its phases, crescent, waxing, waning, and full, as well as gibbous transitions between those phases. This proved the Copernican heliocentric viewpoint, making the Ptolemaic model untenable.

Answer 4

Galileo did not have any reasonably valid evidence at all for the motion of the earth around the sun. One thing which he saw as evidence for the orbiting of the sun by the earth was simply the existence of tidal waves which he believed to be a disturbance of the water by the earth's rotation and revolution. It's like what we see when we try to spin a container of water. Water splashes out. And whether Galileo discovered that the earth was stationary or not wasn't really the cause of the tension between him and the Catholic Church contrary to popular belief. The catholic church supported his belief in heliocentrism, especially the Pope. But they viewed it only as a good "theoretical" model for planetary motion. Because of this Galileo wrote his advocacy for heliocentricism in the form of a dialogue. In this dialogue he created a character who regarded as a fool hence his name "simplicio" (meaning simpleton). This character was an allusion to the pope. That's the "real" reason why he was placed under house arrest.

Answer 5

Galileo believed that the planets followed the system proposed by Copernicus in 1543, with the Sun at the center of the system and the six known planets orbiting round it (including the Earth). This differed from the older Ptolemaic model from ancient times, which placed the Earth at the center.

In the models the planets' orbits consist of combinations of circles. It was realized even by Ptolemy 1400 years before that the planets do not have circular orbits. We now know the orbit is an ellipse.

Galileo compared the two models in his famous book the 'Dialogue of the two world systems' published in 1632, and made it clear that he favored the Copernican model with the Sun at the centre. Not only that, he proclaimed it as the absolute truth after the church had told him not to, and the book contained a character portrayed as a simpleton, which was interpreted by many as a representation of the Pope. The book led to his fall-out with the Catholic Church.

Answer 6

he did swing and jumped

Answer 7

he read copernicus's book.

Answer 8

Copernicus said it happened in the B.c.

Answer 9

He didn't discover it