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322 BCE
Aristotle
Aristotle. He is sometimes called the grandfather of science. He studied under the great philosopher Plato and later started his own school, the Lyceum at Athens. He, too, believed in a geocentric Universe and that the planets and stars were perfect spheres though Earth itself was not -
168
Ptolemy
Ptolemy was an astronomer and mathematician. He believed that the Earth was the center of the Universe. The word for earth in Greek is geo, so we call this idea a "geocentric" theory. -
1543
Copernicus
Copernicus was a Polish astronomer who put forth the theory that the Sun is at rest near the center of the Universe, and that the Earth, spinning on its axis once daily, revolves annually around the Sun. This is called the heliocentric, or Sun-centered, system. -
Tycho Brahe
Tycho Brahe (1546-1601) was a Danish nobleman and astronomer, and he was one of the individuals whose work helped overturn that belief in favor of a heliocentric model of the universe, with the sun at the center. -
Hans Lippershey
Hans is commonly associated with the invention of the telescope, because he was the first one who tried to obtain a patent for it. -
Johannes Kepler
German astronomer who discovered three major laws of planetary motion, conventionally designated as follows: 1. the planets move in elliptical orbits with the Sun at one focus. 2. the time necessary to -
Galileo
Galileo used his newly invented telescope to discover four of the moons circling Jupiter, to study Saturn, to observe the phases of Venus, and to study sunspots on the Sun. Galileo's observations strengthened his belief in Copernicus' theory that Earth and all other planets revolve around the Sun. -
Giovanni Cassini
Giovanni was the first to observe the shadows of Jupiter's satellites as they passed between that planet and the Sun. -
Sir Issac Newton
Newton invented calculus and provided a clear understanding of optics. But his most significant work had to do with forces, and specifically with the development of a universal law of gravity. -
William Herschel
William found the planet Uranus and its two moons, and formulated a theory of stellar evolution. -
Percival Lowell
Lowell was an American astronomer who predicted the existence of a planet beyond the orbit of Neptune and initiated the search that ended in the discovery of Pluto. -
Karl Jansky
Jansky created a development of the new study of radio astronomy -
Edwin Hubble
Hubble proved that the clouds of light astronomers saw in the night sky were actually other galaxies beyond our Milky Way. He also discovered the relationship between a galaxy's distance and the speed with which it is moving. -
Albert Einstein
As a physicist, Einstein had many discoveries, but he is best known for his theory of relativity and the equation E=MC2, which foreshadowed the development of atomic power and the atomic bomb. -
Sputnik
History changed on October 4, 1957, when the Soviet Union successfully launched Sputnik I. The world's first artificial satellite was about the size of a beach ball , and took about 98 minutes to orbit the Earth on its elliptical path. -
Yuri Gagarin
Yuri became the first human to journey into outer space when his Vostok spacecraft completed one orbit of the Earth -
John Glenn
Glenn was the first American to orbit the Earth, circling it three times. -
Ejnar Hertzprung
Danish astronomer who classified types of stars by relating their colour to their absolute brightness. -
Neil Armstrong
Neil Alden Armstrong was an American astronaut and aeronautical engineer who was the first person to walk on the Moon. -
The Apollo Program
the Apollo program, also known as Project Apollo, was the 3rd United States human spaceflight program, which succeeded in landing the first humans on the Moon from 1969 to 1972. -
First Space Shuttle Flight
The first space shuttle flight was April 12 1981. iSTS-1 was the first orbital flight of NASA's Space Shuttle, launched on 12 April 1981, and returning to Earth 14 April. The shuttle was in space for 54 hours and orbited Earth 37 times. -
Mars Pathfinder Expedition
Mars Pathfinder is an American robotic spacecraft that landed a base station with a roving probe on Mars in 1997. a lightweight wheeled robotic Mars rover named Sojourner, which became the first rover to operate outside the Earth–Moon system. -
Cassini Oribter
The Cassini orbiter mission, commonly called Cassini, was a collaboration between NASA, the European Space Agency, and the Italian Space Agency. It was sent study the planet Saturn and its system, including its rings and natural satellites. -
Difference between refracting and reflecting telescopes
A reflector telescope uses two mirrors instead of two lenses. Refraction telescopes use two mirrors. with reflecting telescopes you can see rainbow on some of them.
