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384 BCE
Aristotle
Aristotle was born in Stagira, Greece in 384 B.C. He was a Greek philosopher/ astronomer. He wrote about and taught many subjects like history, philosophy, drama, poetry, and ethics. He understood the geocentric model and the movements in space. Aristotle realized that one sphere model couldn't explain why the stars were in different positions, the sun couldn't follow the same path year round, etc, so he repositioned the model. That's when Aristotle believed that the Earth was at the center. -
100
Ptolemy
Ptolemy was born in Alexandria, Egypt in 100 A.D. He was a philosopher/astronomer who believed that in Earth was the center of our Solar System, this meant all the planets (including the sun) would revolve around the Earth. He also believed that the planets and stars were perfect spheres, thats why he thought the Earth was at the center of our Solar System. Many people believed him at the time because there was no technology developed yet. Ptolemy's theory was called the Geocentric Model. -
1473
Copernicus
Copernicus was born in Toruń, Poland in 1473. Copernicus was the astronomer who put the sun in the middle of our Solar System. After a lot of research, looking to see the errors in Ptolemy's Geocentric Model, Copernicus saw 2 things were wrong his model. First, the planets and stars did not orbit in a perfect sphere, they moved in complicated patterns. And Second, the Earth was not in the center of our Solar System, the sun was. But sadly not very much people believed in his Heliocentric Model. -
1546
Tycho Brahe
Tycho Brahe was the astronomer that made consistent observations which supported the Heliocentric theory proposed earlier by Copernicus, and lead to new discoveries and other observations. The observations about Copernicus´ theory/ Heliocentric Model were used using a compass and a sextant. Brahe discovered over 1000 stars in our universe. He also proved that comets were not just pieces of Earth´s atmosphere, but real objects traveling in space. -
1564
Galileo
Galileo was a Italian astronomer that invented something to help us discover more thing in space or far away from us. In 1609, Galileo heard about the invention of the spyglass, a device which made objects far away appear closer. Galileo wanted to improve the spyglass and make it better, so he used his mathematics, knowledge, and technical skills to build a telescope. Later that same year. he became the first person to look at the moon through a telescope and make his first astronomy discovery. -
1570
Hans Lippershey
Hans Lippershey was a Dutch inventor that was the spectacle maker for the telescope with Galileo Project. He was the first person who tried to get the telescope patented. However, it is uncertain if he got it patented successfully. -
1571
Jonhannes Kepler
Johannes Kepler was the astronomer/ philosopher who created the three Major Laws of Planetary Motion. The first planetary law was the planets move in elliptical orbits with the Sun at one focus. The second planetary law was the time necessary to traverse any arc of a planetary orbit is proportional to the area of the sector between the central body and the arc. And the third and final planetary law was there is an exact relationship between the squares of the planets' periodic times. -
Giovanni Cassini
Giovanni Cassini was the Italian astronomer that discovered the Cassini Division, the dark gap between the rings A and B of Saturn. He also discovered four of Saturn´s moons. Giovanni Cassini earlier studies were mostly about the sun, but after he got his hands on one of the best inventions for astronomy, the telescope, he turned his attention to the planets. -
Sir Isaac Newton
Sir Isaac Newton was the astronomer who show us motion in the Earth. He wanted to be a Famous Astronomer. After a lot of scientific studies, he made a lot of scientific discoveries and inventions. He came up with The 3 Laws of Motion. 1) That an object at rest tends to stay at rest, and an object in motion tends to stays in motion. 2) That the acceleration of an object made by a applied force is directly related to magnitude. 3) That for every action there is an equal and opposite reaction. -
William Herschel
Sir William was a German astronomer who is widely credited as the founder of Uranus and its two moons, Titania and Oberon, and the of the stellar evolution. Also in 1816 he was the first astronomer to suggest that the nebulae are composed of stars. -
Percival Lowell
Percival Lowell was an American astronomer who predicted the existence of a planet beyond the orbit of Neptune and initiated the search that ended the discovery of Pluto. -
Enjar Hertzsprung
Enjar Hertzsprung was a Danish astronomer who classified types of stars by relating their colour to their absolute brightness an accomplishment of fundamental importance to modern astronomy. The Hertzsprung-Russell diagram of stellar types was named after him. -
Albert Einstein
Albert Einstein was a German astronomer who came up with the field equations of gravitation. The theory described how gravity is the result of the distortion of space, and how when objects travel close to the speed of light, their lengths contract and the time slows down. His theory also predicted the existence of gravitational waves, which were actually only officially observed very recently, even though he predicted them 100 years ago. -
Edwin Humble
Edwin Humble is an American astronomer/ man who discovered cosmos in our Earth. Cosmology is the science of the origin and development of our universe. -
Karl Jansky
Karl Jansky was an American astronomer that discovered the radio astronomy, a new science that from an extraterrestrial source, and did the first systematic survey of radio waves from sky. He also discovered found the direction of the constellation Sagittarius. -
John Glenn
On February 20, 1962. John Glenn became the first American to orbit the Earth on this date. In 4 hours and 56 minutes, he circled the globe three times in his space capsule Friendship 7. -
Neil Armstrong
Neil Armstrong was an American astronaut that was the first person to be on the moon. He had the first experience on knowing how to walk or how to be on the moon. -
Yuri Gagarin
Yuri Gagarin joined the Russian Air Force in 1955 and graduated with honors from the Soviet Air Force Academy in 1957. Soon afterward, he became a military fighter pilot, but by 1959 he had been selected for cosmonaut. Gagarin flew only space mission, and became the first human to orbit Earth. -
Sputnik
History changed on October 4, 1957, when the Soviet Union successfully launched the Sputnik, the world's first artificial satellite. The Launch ushered in political, military, technological, and scientific developments. -
The Apollo Program
The Apollo Program started in 1961 and ended 1972. The Apollo program was designed to land humans on the moon and bring them safely back to Earth. 6 out of 17 missions were accomplished. -
First Space Shuttle Flight
The first space shuttle flight was on April 12 1981. Columbia was the first shuttle to reach space, in 1981. The Columbia carried dozens of astronauts into space. But ever since then, society has been making more improvements and adjustments. -
Mars Pathfinder Expedition
The Mars Pathfinder Expedition was launched on December 4, 1996 and landed on Mar's Ares Vallis on July 4, 1997. It was designed as a technology demonstration of a new way to deliver an instrumental lander and the first-ever robotic rover to the surface of the red planet. It also means this was when they first came to Mars and explored it. -
Cassini Orbiter
The spacecraft was capable of taking accurate measurements and detailed images. -
Difference between refracting and reflecting telescopes
A reflector telescope uses two mirrors instead of two lenses, and a refractor telescope uses two lenses. -
Pluto at Solar Conjuction
Pluto will pass very close to the Sun in the sky as its orbit carries t around the far side of the solar system from the Earth. At the closest approach, Pluto will appear at separation of only 7 degrees from the sun, making it totally unobservable for serval weeks while it is lost in the Sun's glare.
