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Period: 384 BCE to 322 BCE
Aristotle
He believed the Earth was the center of the universe and that all objects moved in perfect circles. -
Period: 100 BCE to 170
Ptolemy
He created the geocentric model that placed Earth at the center of the universe. -
Period: 1473 to 1543
Copernicus
He proposed the heliocentric model where the Sun is at the center of the solar system. -
Period: 1546 to
Tycho Brahe
He made very accurate observations of stars and planets without a telescope. -
Period: 1571 to
Johannes Kepler
He discovered that planets move in elliptical orbits around the Sun. -
Galileo Galilei recreates the telescope
In 1609, Galileo Galilei improved the design of the telescope, increasing its magnification up to 30 times, and used it to make groundbreaking astronomical discoveries, such as observing mountains and craters on the Moon, discovering four moons orbiting Jupiter, identifying countless stars in the Milky Way, and providing strong evidence for the heliocentric model of the solar system, which proposed that the Earth and other planets revolve around the Sun. -
Galilea discovers Jupiter’s biggest moons
In 1610, using a telescope he had improved himself, Galileo Galilei discovered the four largest moons of Jupiter—Io, Europa, Ganymede, and Callisto—by observing tiny points of light that appeared to move around the planet night after night, leading him to realize they were orbiting Jupiter, not Earth. -
Isaac newton discovers calculus
In the late 1660 Isaac newton discovers calculus. -
Issac newton discovers gravity
Isaac Newton discovered the concept of gravity after observing an apple fall from a tree, which led him to wonder why objects always fall straight down, inspiring him to theorize that a universal force, which he later called gravity, pulls all objects toward one another, and that this same force governs the motion of planets and moons in space. -
Period: to
William Herschel
He discovered Uranus and built powerful telescopes. -
Period: to
Edwin Hubble
He showed that the universe is expanding as galaxies move away from us. -
Albert Einstein creates e=mc^2