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270
Aristarchus creates the first known Heliocentric model of our Solar System
Aristarchus believed that our Solar System was heliocentric, or sun-centered. However, he was widely disbelieved. Therefore, geocentric models of the Solar System were more popular. This was in 270 BCE -
Period: 270 to
Space Exploration Time Span
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350
Aristotle Creates a geocentric model of our Solar System
Aristotle creates a geocentric model of our Solar System. His main competitor was Aristarchus with his heliocentric model. Aristotle's model, however, was believed to be correct. This occured in about 350 BCE -
526
Ptolemy made mathematical models proving geocentricity
In 180-200 CE, an astronomer and mathematician named Ptolemy made mathematical models confirming Aristotle's geocentric theory. These models stood for nearly 1400 years. -
Apr 1, 1525
Copernicus revives heliocentricity theory
The polish astronomer and mathematician Nicolaus Copernicus revives Aristarchus' heliocentricity theory with math to back it. -
Galileo
One of the most famous astronomers of all time, Galileo confirmed our Solar System's heliocentricity, in addition to discovering gravity. -
First rocket capable of entering space
During WWII, Nazi scienctists created the V-2 airborne liquid fuelled rocket. It was the first one that was able to enter space. The Nazi scientists later helped the U.S. build the Apollo and other space rockets. -
Sputnik 1 is launched
Sputnik 1 is the first artificial satellite to be launche dinto an orbit. It was only about the size of a beachball, and took 98 minutes to orbit Earth. -
Yuri Gagarin enters space
Russian cosmonaut Yuri Gagarin was the first man in space. He was sent into an elliptical orbit inside Vostok 1, a small Soviet space craft. He later died in an accident at an airfield. This was the first example of an orbital mission, one of many following in the space race between Russia and the U.S. -
Neil Armstrong lands on the Moon
Neil Armstrong became the frist man to land on the moon. This was the first of 6 moon landings soon to follow. -
First mars robotic explorer is launched
The first mars lander, named Sojourner, was landed on July 4th, 1997. It was originally designed to demonstrate that you could send a lander there at a relatively low cost. -
Demotion of Pluto
Pluto, one of the outer planets and (at least, it used to be) the farthest from our Sun. But, it got demoted to being a dwarf planet.
