He discovered Uranus while surveying the stars in the night sky by using a telescope he built himself.
He argued that the observed frequency of an electromagnetic save or sound wave depends on the relative speed of the source and the observer.
The theory of relativity explains the law of gravitation and its relation to other forces of nature.
At the time of discovery, Pluto was considered a planet but was later reclassified as a dwarf planet in 2006.
This was the U.S satellite to orbit earth.
Apollo 11 was the spaceflight that first landed humans on the Moon. ... Armstrong and Aldrin
On the seventh anniversary of the Apollo 11 lunar landing, the Viking 1 lander, an unmanned U.S. planetary probe, becomes the first spacecraft to successfully land on the surface of Mars.
Galileo was the first spacecraft to examine Jupiter and its moons for an extended period.