WORLD CIVILIZATION

Detailed explanation-1: -In 1543, Nicolaus Copernicus detailed his radical theory of the Universe in which the Earth, along with the other planets, rotated around the Sun. His theory took more than a century to become widely accepted.

Detailed explanation-2: -Galileo Galilei made an important discovery about Venus much later. He observed the planet not only waxing and waning through a telescope, but also appearing to change size.

Detailed explanation-3: -Ancient astronomers were able to make geometric observations with various instruments. The collection of precise observations in the early modern period and the invention of the telescope helped determine the overall structure of the Solar System.

Detailed explanation-4: -In 1930, Pluto was discovered and officially named the ninth planet. However, in 1978, Pluto was determined to be too low in mass to have caused these perturbations, so the possibility of a tenth planet was proposed.