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384 BCE
Aristotle
Aristotle was known for his belief in a geocentric universe. A geocentric universe is one that represents Earth in the middle and all the planets orbiting around Earth. He also believed that all the stars and planets were spheres except Earth. Aristotle was born in 384 and died in 322. In 335 Aristotle founded his own school in Athens where he spent most of his life studying, teaching, and writing. -
100
Ptolemy
Ptolemy is known for being a mathematician. A mathematician is a expert in mathematics. He was born in 100 and died in 168. The Ptolemaic system is a geocentric cosmology. A geocentric cosmology is one that represents Earth in the center and all the planets orbiting around Earth. -
1473
Copernicus
Copernicus was born in 1473 and died in 1543. In the early 1500s when everyone believed Earth was the center of the universe, Copernicus proposed that the planets revolved around the Sun. Copernicus's model of the universe was known as the heliocentric universe. -
1564
Tycho Brahe
Tycho was born in 1546 and died in 1601. He was known for turning around the belief of the people that we lived in a geocentric universe. He was a Danish nobleman and astronomer. His work involved developing astronomical instruments like the telescope. He also measured and fixed the positions of the stars for future discoveries. He created more than 777 fixed positions for stars. -
1564
Galileo
Galileo was born in 1564 and died in 1642. He was a Italian astronomer. Galileo invented another version of the telescope and was a supporter of the Copernican theory. The Copernican theory supports that the Sun is motionless in the center of the universe and all the other planets are orbiting around the Sun. -
1570
Hans Lippershey
Hans was born in 1570 and died in 1619. Hans invented the kijker. It was also known as the looker. The looker was an instrument that had two lenses held in place so that an observer could look through at distant objects. -
1571
Johannes Kepler
Johannes Kepler was born in 1571 and died in 1630. Johannes is best known for his laws of planetary motion. -
Giovanni Cassini
Giovanni was born in 1625 and died in 1712. He was a astronomer. -
Sir Isaac Newton
Newton was born in 1643 and died in 1724. Newton worked on universal gravitation also known as gravity. Newton also developed the three laws of motion. The first law states that an object will remain at rest until it is struck with a certain amount of force. -
William Herschel
William was born in 1738 and died in 1822. William was an astronomer that was widely known for being the founder of sidereal astronomy. Sidereal astronomy helps astronomers keep time and know where to point their telescopes without having to know where the Earth was in its orbit. -
Percival Lowell
Lowell was born in 1855 and died in 1916. Lowell is best known for his belief that there as life on Mars. He also founded the Lowell Observatory in Flagstaff. -
Ejnar Hertzsprung
Ejnar was born in 1873 and died in 1967. Ejnar became a chemical engineer. -
Albert Einstein
Albert was born in 1879 and died in 1955. In 1921 he won the nobel prize for physics for his explanation of the photoelectric effect. The photoelectric effect is -
Edwin Hubble
Edwin was born in 1889 and died in 1953. Edwin discovered cosmology. Cosmology is the science of the origin and development of the universe. -
Karl Jansky
Karl was born in 1905 and died 1950. Karl investigated the sources of static that might interfere with radio transmission. -
John Glenn
John was born in 1921 and died in 2016. John was chosen to be apart of the newly formed NASA program. John was the first American to fully orbit around the Earth. -
Neil Armstrong
Neil was born in 1930 and died in 2012. Neil was the first human to walk on the Moon. -
Yuri Gagarin
Yuri was the first person to fly in space. His flight lasted 108 minutes while he orbited around the Earth. -
Sputnik
The Sputnik was the first satellite launched into space man. The satellite fell back to Earth in 1958. -
The Apollo Program
The Apollo Program started in 1963 and ended in 1972. The program was designed to safely land and bring back humans from the Moon. 6 out of 17 of these missions were accomplished. -
The First Space Shuttle Flight
NASA launched the first space shuttle into orbit in 1981. -
Mars Pathfinder Expedition
The expedition was launched in 1996. It landed on Mars Ares Vallis in 1997. -
Cassini Orbiter
The spacecraft was capable of taking accurate measurements and detailed images. It was launched in 1997. -
The difference between refracting and reflecting telescopes
A refractor telescope uses two lenses where on the other hand a refletor telescope uses two mirrors. -
Voyager 1
The Voyager 1 was the first aircraft to reach interstellar space. Interstellar space is the place in space where the Sun's constant flow of material and magnetic field stops affecting its surroundings.
