Geocentric Theory . Aristotle believed that the Earth was the center of the universe because it was the heaviest of the four terrestrial elements (earth, water, air, fire). The lighter the element, the further it was away from the earth. That is why the sun isn’t the closest thing to the sun.
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almost 2000 years later Nicolaus Copernicus became interested in an old Greek idea that the sun stood at the center of the universe. After studying planetary movements for 25 years, Copernicus reached the conclusion that the stars, earth and the other planets revolved around the sun, otherwise known as the Heliocentric Theory.
He also knew that most scholars and clergy would reject his theory because it contradicted their religious views, so he didn’t publish his findings until the last year of his life (1543)
The first microscope was invented by a Dutch maker of eyeglasses Zacharias Janssen in 1590
In the 1670s a Dutch drapery merchant and amateur scientist named Anton van Leeuwenhook used a microscope to observe bacteria swimming in tooth scrapings.