Mikołaj Kopernik
Galieo was the first astronomer to view Jupiter's moons through a telescope and proved the heliocentric model.
It proved that curvatures of light around black holes existed.
The popular answer to this question would be Galileo. However, contrary to popular belief Galileo did not invent the telescope. He built his own telescope about a year after their initial creation and later made significant improvements.
Konstantin Tsiolkovsky proved scientifically that rockets could reach outer space.
Isaac Newton
Copernicus.
Copernicus proved that the earth is flat and that we are NOT the center of all the universe. He also proved that planets rotate around the sun. He was also a well respected astronomer.
In the Dark Age of Science, it was believed that Earth was in the center of Solar System and all the planets including sun, revolve round the sun. This is called Geocentric Theory.Nicolas Copernicus, A Polish*Astronomer, proved that earth and other planets revolved round the sun. This is Heliocentric Theory.(Copernicus proposed the Heliocentric Theory in 1543, 64 years before the invention of telescope. I was all the work of his Mathematics.)_________________________________________________________________* Polish Astronomer is an Astronomer from Poland
Michael carter jr.
Tych Brahe
Ben Obando
Johannes Kepler
The astronomer's observations proved that cephid variable stars would pulsate in a regular cycle
william herschel
Galieo was the first astronomer to view Jupiter's moons through a telescope and proved the heliocentric model.
You may be thinking of William Harvey, who was the first to describe the circulatory system in some detail.
Galileo