s have “known” that the earth was flat, that the Sun and other planets revolved around the Earth, and that Newton had an apple hit him in the head.
In the 17th century A.D., it was believed that all combustible substances contained a particular material that was released when they were burned. In the early 1700s, one Georg Ernst Stahl called this burnable material “phlogiston” and he promoted the idea that wood was made of wood ash and phlogiston, while rustable metals were made of metallic ash and phlogiston. Whether phlogiston was an actual physical thing or just a principle, the air involved was considered merely responsible for carrying off the phlogiston freed by the burning process.
Within a hundred years, however, phlogiston was cast aside as an explanation for why things burned. In the late 18th century, Antoine Lavoisier carefully measured the weights of various substances that went through oxidation or reduction reactions, and he demonstrated that oxygen was the culprit involved.
Wrong ideas often last longer than they should because we humans tend to get hooked on ideas rather than on truth. People in history who believed that the Earth was flat should have read the Bible:
It is he that sitteth upon the circle of the earth, and the inhabitants thereof are as grasshoppers; that stretcheth out the heavens as a curtain, and spreadeth them out as a tent to dwell in:
— Isaiah 40:22
Wrong Ideas – Geocentrism
For millennia people believed that the Earth was the center of the solar system. Ptolemy of Alexandria developed the geocentric model in his works Almagest and Planetary Hypotheses. His picture of the solar system was known ever after as the Ptolemaic Model. For the next 1400–1500 years, people believed as a matter of course that the Sun (and the rest of the sky) revolved around Earth every day. The Sun rose in the morning on one side of the planet and set on the other side in the evening. It took quiet Copernicus and loud Galileo to point out facts that required the alternative: Earth and other planets revolved around the Sun.
Yet, acceptance of the Copernican cosmology took quite a long time despite the fact that it fit careful observation of the facts much better than the model Ptolemy had offered. Copernicus first wrote about his heliocentric ideas in the early 1500s, and it was a full century later that Kepler supported those ideas with discussions on the elliptical orbit of Mars. About the same time, Galileo affirmed Copernicus through the use of a telescope. Even then, Copernicus’ heliocentric theory was banned in 1616, and it took most of the 17th century for the idea that the Earth revolved around the Sun to take root in people’s minds. Isaac Newton helped cement the idea with his work on gravitation, but it took until 1758 for the Roman Catholic Church to finally end its prohibition on books that taught heliocentrism.
Poor Ptolemy of Alexandria. He has gone down in history as the scientist who got it wrong on two fundamental truths in science. He was incorrect about the Earth as the center of the solar system, and he argued against the possibility of four dimensions.
Wrong Ideas – Aether
For many moons, astronomers and cosmologists believed the universe was filled with a material called the aether. Light was understood to be a wave, which meant it needed a medium through which it could travel, like waves on a cosmological pond. Aether was considered the pond through which light traveled across the universe. The aether was seen as an absolute reference frame in respect to the rest of the universe; everything had its speed in reference to the aether.
In 1887, the Michelson-Morley experiment attempted to measure the speed of aether itself. Michelson and Morley expected that as light traveled with the aether, it would race along faster, and as it traveled against the aether, it would move slower. They set up a detection device with a light source, mirrors and a telescope, and they found that no matter where the Earth was in its rotation around the Sun, the light always traveled at the same speed. This was 