4th Century B.C. The Geocentric theory was thought up by Plato and his apprentice Aristotle.
Galileo made the first telescope in 1610 and presented it on 1611.
390 B.C. The Heliocentric theory went through many astronomers but made an entry through many scholars by Galileo Galilei. Pythagoreans (the cult of Pythagoras) and mostly Philolaus (a Pythagorean) were thought to have made some sort of infrastructure. The first person to propose the idea of Heliocentrism was Aristarchus of Samos and a cult grew called the followers of Aristarchus. Indian philosopher Aryabhata, the man that discovered that pi was irrational, had some theory of Heliocentrism as well. Galileo Galilei is the most famous for his work for Heliocentrism.
October 4, 1957, The unmanned spacecraft Sputnik 1 was launched successfully into space. It was the first Earth satellite. It was from the USSR.
November 3, 1957, Laika was a space dog which was in the spacecraft Sputnik 2. She died from overheating but was the first living thing from Earth in space. Laika was also the first animal to orbit the Earth which paved the way for human space flight.
On February 17, 1959, The first photograph was taken of the earth by a US naval satellite called the Vanguard 2.
April 12, 1961, Yuri Gagarin becomes the first man in space. He was carried in the Vostok 1. He was from the Soviet Union. He died in 1968 from a jet crash.
From the Mercury expedition, John Glenn became the first US man to reach space.
The first woman of USSR decent is sent of to space.
The ship Voskhod 2 had the first man Alexey Leonov walk. This ship also was USSR.
Apollo 11 was launched by the US and the first man on the moon was Neil Armstrong.
The Soyuz/Apollo missions from then on were coop with are new found companion the Russians.
The whole crew died.
The whole crew died in the explosion.
The SpaceShipOne was the first private space plane that was designed by Burt Rutan.