Famous "Scientific" Theories and Who Replaced Them with Real Scientific Theories

1. Ptolemy (~100 CE to ~170 CE) said that all planets orbit the Sun in circular orbits. To explain the retrograde movements of the outer planets known at the time, Jupiter and Saturn, Ptolemy said that they also moved in additional circles called "deferents."

Nicholaus Copernicus (19 February 1473-24 May 1953) simplified planetary orbits by discovering that the planets move around the Sun in elliptical orbits.

2. Phlogiston: Phlogiston was thought to be a substance with negative weight. In a fireplace, phlogiston entered into the firewood, making it rise in the chimney as smoke and reducing the firewood to light-weight ashes.

Between 1770 and 1790, Antoine Lavoisier proved that oxygen combines with hydrocarbons in the firewood, producing light, heat, carbon dioxide, and water vapor. These four products escape from the fireplace or rise through the chimney. Without hydrocarbons, firewood is reduced to ashes.

3. During a solar eclipse, sunlight seems to move other stars away from the Sun, as carefully measured on astronomical photographic plates in comparison with other plates made when there was no eclipse. This led to the theory that the Sun could push other stars away from it.
Albert Einstein proved that the gravity of the Sun bends the starlight toward it, making it appear to a naive observer that the star had moved away from the Sun. Arthur Eddington's photos of the eclipse of 21 May 1919 showed star image displacements that agreed exactly with Einstein's predictions, and Einstein became famous throughout the world.