The Four Humours
For physicians and scientists of antiquity, the body was composed of four humours – phlegm, yellow bile, black bile, and blood. If your body wasn’t producing a healthy balance of these humours, then you would get sick. This is why blood letting was so common up until the 1800’s (then we found out about germs).
This was the idea that miasma (bad air) is responsible for disease. Prior to the introduction of germ theory in the late 1800’s, this was the most widely accepted explanation for why people got sick. The results of this theory led to some rather interesting medical solutions. During the Middle Ages doctors would prescribe “fart smelling.” Apparently it was believed that like cures like, and if bad air caused the disease…bad air could cure it.
The Earth as the Center of the Universe
Thanks to Nicolaus Copernicus, the Ptolemaic model of the Solar System (with the Earth at the center), was replaced with our current understanding.
Hypothesized in the 1600’s by Johann Joachim Becher, this “element” was meant to explain burning. Also, it was believed that humans didn’t breathe to get oxygen…they breathed to expel phlogiston so they wouldn’t start burning.
Neanderthals and Humans Didn’t Mix
Actually, after the neanderthal gene was sequenced in 2010, scientists found that up to 4% of people living outside of Africa have neanderthal DNA. This means that there was some cross breeding.
Genetic Variance between Human Races
Actually, there isn’t much genetic variance between human races at all. Recent studies in the 21st century have even shown more variance between African tribes than between Africans and Europeans.
Pluto is a Planet
Well, at first it wasn’t. Then it was. And now it isn’t again.
Ulcers are Caused by Stress
Wrong. Ulcers are caused by bacteria, and the researchers that proved it actually won the Nobel Prize in 2005. In fact, one of the researchers even ingested the bacteria to prove it.
While this used to be widely accepted (and widely refuted), there are still people out there that believe this. Just look up the Flat Earth Society.
This theory held that inner character was influenced by physical appearance, specifically the measurements of the skull.
The "Unbreakable" Laws of Newtonian Physics
Quantum mechanics completely changed the way we understand the world. On a quantum level, things get crazy in ways that are hard to comprehend.
It’s funny because everybody has heard the phrase, “California is an island unto itself.” This metaphorical phrase used to be taken quite literally though. It wasn’t until expeditions late in the 1700’s that map makers realized California was in fact part of North America.
This was the idea that offspring could inherit traits from the previous mates of their mother. This theory was highly favored among Nazis who believed that an Aryan woman who had intercourse with a non-Aryan man could no longer have a “pure” Aryan child.
Pythagoras and his followers were almost religiously obsessed with numbers. One of their key doctrines was that all numbers could be expressed as the ratio of integers. So when Hippasus pointed out that the square root of 2 was irrational…it shocked the Pythagoreans, and they had him drowned at sea.
Hollow Earth Theory
If you’ve ever read A Journey to the Center of the Earth then you are familiar with this theory. Up until the late 1800’s, some people believed that the center of the Earth might contain, well…nothing.
Although the Greeks were ahead of their time in many ways, they held a crazy belief that you could grow lambs on trees. This belief allegedly arose out of stories coming from the Indies, where people described trees on “which wool grew.” The idea of lambs growing on trees persisted well into the 1600’s.
Time is Constant
Not since Einstein. When he showed that light was the only constant, the world thought he was crazy. These days, however, NASA has to adjust its clocks because time runs differently depending on how far you are from a source of gravity and how fast you are going. In fact, a clock at sea level ticks faster than a clock at the top of the Empire State Building.
Complex Organisms = More Genes
Scientists used to think that humans have around 100,000 genes. One of the most surprising things to come out of the Human Genome Project was that we in fact have only about 20,000. And the crazy part? Some tiny moss plants have more than 30,000!
Water Only Found on Earth
As NASA recently discovered, there is more water on Jupiter’s moon of Europa than there is on our own planet.
Apes: the Smartest Non-Human Animal
According to recent research, birds are quite intelligent. In fact, some studies have shown them to be even smarter than apes.
King Tut's Death
In 2006, historians found evidence that King Tut had died in a chariot accident. In 2014, however, scientists discovered that he had in fact died because of inbreeding.
Intelligence of Neanderthals
In the past, it was thought that Neanderthals died out because Homo sapiens were smarter. New evidence contradicts this. According to researchers, neanderthals may have even been more intelligent than our human ancestors. Why did they die out then? We’re not quite sure.
The Speed of Universe Expansion
The prominent view of the cosmos until recently was that the expansion of the universe is slowing down because of gravity. In the 1990’s, however, new evidence showed that the expansion of the universe was in fact speeding up.
Dinosaurs had leathery skin
Actually, scientists have now come to the conclusion that they were mostly covered in feathers.
Although Sir Isaac Newton made massive contributions to physics, he remained convinced that he could convert base metals into gold. Thanks to alchemy, however, today we have chemistry.