Rejection of Heliocentrism:
This happened in the year 1918 when the astronomer Harlow Shapley (1885-1972) first surveyed the size and shape of the Milky Way Galaxy. He showed, by his most original researches, that the Sun does not lie at the centre of the Milky Way Galaxy, but is located a great distance away from the centre. But the question whether the Milky Way Galaxy was the whole of the universe or not, still remainsd. The answer came in the year 1924, when Edwin Hubble (1889-1953), another great astronomer, showed that the fuzzy cloud called Andromeda nebula was not a member of the Milky Way Galaxy. In fact it was a separate galaxy. Soon, other galaxies were spotted, but the Milky Way Galaxy appeared to be the largest. This was some consolation to the human ego: if the centre of the universe was neither reserved for our Earth, nor for our Sun, at least we lived within the largest galaxy. This idea also did not last long. Walter Baade (1893-1959) turned the telescope on many cosmic details that Hqbble had skipped over. He discovered that the other galaxies were farther away than we had supposed, and the Milky Way Galaxy was no bigger than the others. It was merely one galaxy among countless others.
The revolution that had begun with Copernicus was now complete. We had no special place in this universe! We were not at its centre. In fact, the universe was found to have no centre and not even a boundary. Indeed, the greatness of Copernican ideas lies not so much in what Copernicus did as what his work led to.