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322 BCE
Aristotle
384-322 BC. Aristotle was a Greek philosopher. The Sun, Moon, stars, and planets all orbited Earth. The geocentric model served as the predominant description of the cosmos in many ancient civilizations, such as those of Aristotle. Observations supported the idea that Earth was the center of the Universe. -
168
Ptolemy
100-168 AD. Ptolemy was Roman mathematician, astronomer, geographer, and astrologer. Ptolemy postulating that the apparently irregular movements were a combination of several regular circular motions seen in perspective from a stationary Earth. -
1543
Copernicus
1473-1543. Copernicus was a German-Polish astronomer who helped found the discipline of astronomy when he said that the earth was a moving planet. He believed that the sun and not the earth, was the center of the universe. -
Tycho Brahe
1546-1601. Tycho Brahe was a Danish nobleman, astronomer, and writer known for his astronomical and planetary observations. He observed the night sky before the invention of the telescope -
Hans Lippershey
1570-1619. Hans Lippershey, was a German-Dutch spectacle-maker. Many people associate him with the invention of the telescope, because he was the first one who tried to get a patent for it. But it is unclear if he was the first one to build it. -
Johannes Kepler
1571-1630. Johannes Kepler was a German astronomer and mathematician. He discovered the laws of planetary motion. His success was also because of his inventions that allowed him and others to make new discoveries. -
Galileo
1564-1642. Galileo was an Italian astronomer, physicist and engineer, also described as a polymath. Galileo discovered that the Moon was far from being smooth, and unlike Earth, had mountains and craters. -
Difference between refracting and reflecting telescopes
The difference between a refracting and a reflecting telescope is their optical construction. The refracting telescope uses a system of lenses to refract light rays, but a reflecting telescope uses a system of mirrors to reflect light rays. -
Giovanni Cassini
1625-1712. Giovanni Cassini was an Italian mathematician, astronomer and engineer.Cassini is known for his work in astronomy and engineering. Cassini discovered four satellites of the planet Saturn and also noted the division of the rings of Saturn. The Cassini Division was named after him. -
Sir Isaac Newton
1643-1724. Sir Isaac Newton was an English mathematician, physicist, astronomer, theologian, and author who is recognized as one of the most influential scientists of all time. Newton explained gravity as the force that holds up all the planets and the sun. -
William Herschel
1738-1822. William Herschel was a German-born British astronomer and composer. He is widely known as the founder of sidereal astronomy for observing the heavenly bodies. -
Percival Lowell
1855-1916. Percival Lowell was an American businessman, author, mathematician, and astronomer. He fueled speculation that there were canals on Mars. He studied Mars thoroughly and published three books on his views. -
Karl Jansky
1905-1950. Karl Jansky was an American physicist and radio engineer. He is known for discovering radio waves emanating from the Milky Way. He received radio waves from the Milky Way in 1929. -
Edwin Hubble
1889-1953. Edwin Hubble was an American astronomer. He played an important role in establishing the fields of extragalactic astronomy and observational cosmology.He is known as one of the most important astronomers of all time. -
Albert Einstein
1879-1955. Albert Einstein was a German-born theoretical physicist who developed the theory of relativity. His work is also known for its influence on the philosophy of science. Many people best known him for his mass–energy equivalence formula E = mc² -
Sputnik
- Sputnik is the name given to a series of scientific research satellites launched during the period from 1957 to 1961. The satellites. Sputnik one was the first artificial earth satellite. Its radio signal was very easy to find.
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Ejnar Hertzsprung
1873-1967. Ejnar Hertzsprung was a Danish chemist and astronomer. He classified types of stars by relating their color to their absolute brightness. He was an accomplishment of fundamental importance to modern astronomy. -
Yuri Gagarin
1934-1968. Yuri Gagarin was a Russian Soviet pilot and cosmonaut. He became the first human to go into outer space when his spacecraft completed one orbit of the Earth on April 12th 1961. His flight lasted 2 hours. -
The Apollo Program
1963-1972. The Apollo program, or known as Project Apollo was the third United States human spaceflight program. This was carried out by the National Aeronautics and Space Administration. This succeeded landing the first people on the moon. -
1981 First Space Shuttle Flight
- The first launch of the Space Shuttle occurred on 12 April 1981. The Space Shuttle was a partially reusable low Earth orbital spacecraft system operated by (NASA), as part of the Space Shuttle program.
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1996 Mars Pathfinder Expedition
- The Mars Pathfinder is an American robotic spacecraft that landed a base station with a roving probe on Mars in 1997. It consisted of a lander, and a lightweight wheeled robotic Mars rover, which became the first rover to operate outside the Earth–Moon system.
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1997 Cassini Orbiter
- Cassini-Huygens was a three-axis stabilized spacecraft. On Oct. 15 1997, a seven-year journey to the ringed planet Saturn began with the liftoff of the Cassini Orbiter.
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Neil Armstrong
1930-2012. Neil Alden Armstrong was an American astronaut, aeronautical engineer, naval aviator, test pilot, and university professor. He is known for being the first person to walk on moon. -
John Glenn 1962
1921-2016. John Glenn was a U.S Marine Corps aviator, engineer, astronaut, businessman, and politician. Many people know him because he was the first American to orbit the Earth. He circled 3 times.
