-
240 BCE
Eratosthenes calculations
Eratosthenes is most famous for making the first accurate measurement of Earth's circumference. He knew that at noon on the summer solstice, the Sun was directly overhead town of Syene, because there was no shadow at the bottom of a well in the Egyptian town. He measured the length of the shadow of a tall tower in his home city of Alexandria during a solstice, and then determined the distance between Syene and Alexandria, he was able to calculate the circumference of the Earth. -
170 BCE
Claudius Ptolemy
He argued that Earth is a stationary sphere that sits inside a celestial sphere that spins around it. And that the sphere carried the stars and sun and planets and trace their rings into orbits. -
1543
Nicolaus Copernicus published book
Just two months before his death, Copernicus finally published his book. In it was his statement that the sun was the actual center of the solar system instead of the earth. It was extremely significant because it set the foundation for other astronomers to dive further into this theory and later prove it correct. However, the church shortly banned it after it was published due to it being “heretical”. -
Period: 1546 to
Tycho Brahe Heliocentric contribution
His life’s work and discoveries all supported the heliocentric theory stating that the sun is at the center of the universe. It was significant because everyone believed the earth was at the center during that time period. -
Johannes Kepler
The Martian problem was a confusing thing for all astronomers. No one could figure out why Mars appeared to travel backwards across the night sky. What Kepler thought he could figure out in 8 days took nearly 8 years. Kepler figured out that the planets travel in stretched circles, or ellipses. Earth’s orbit is very close to earth but Mars has one of the most eccentric orbits that is widely stretched. Kepler discovered the fact that planets travel on elliptical paths. -
Period: to
Sir Isaac Newton Laws of motion in the universe
He determined the three laws laws of motion in the universe. From those laws, Newton was able to figure out the law of gravity. All these law discoveries helped scientists understand more about the universe and the planets in our solar system, along with the moon around earth. -
Albert Einstein Theory of General Relativity
in 1905, Einstein concluded that the laws of physics are the same for all non-accelerating observers. Also the speed of light in a vacuum was independent of the motion of all observers. It proposed new concepts of space and time and provided a whole new frame work of physics.