Astronomy Timeline

Aristotle

322 BCE

Aristotle- They believed that Earth is spherical, and the center of the universe and sun, moon and stars traveled in separate spheres.

Hipparchus

122 BCE

Hipparchus- Discovered the precession of the equinoxes. He was also the founder of trigonometry. He also calculated the length of the year and the distance between Earth and the moon.

Ptolemy

170

Ptolemy- the geocentric model he created is the superseded description of the universe with Earth in the center. This supported that the Earth is the center of the universe. Geo means Earth and centric means the earth centered, he also named his theory Ptolemaic is named after himself.

Copernicus

1543

Copernicus- He created a diagram that shows the Sun is near the center of the universe, with Earth and other planets orbiting around it in circular paths. Also at uniform speeds. The heliocentric model was named after the prefix helio which means the sun.

Tycho Brahe

1601

Tycho Brahe- He was known for his accurate observations, he had enough data to prove that stars are in fixed positions and planets to within 1 arc minute.

Refracting Telescope

1608

Refracting Telescope- a telescope that uses a converging lens to collect the light. A reflecting telescope uses a mirror to bounce off the light and focus to a smaller area while the refracting uses lenses to gain light to the other end.

Hans Lippershey

1619

Lippershey- He invented the telescope, his telescope was 3x. He even sometimes credited to the compound microscope.

Johannes Kepler

1630

Kepler- Worked with Tycho Brahe, and he believed that the orbits are in ovals and also discovered the laws of planetary motion. He was the founder of ellipse.

Galileo

1642

Galileo- He was born in Italy and Galileo discovered Jupiter's 4 largest moons which were called. From his telescope, the moons are known as the Galilean moons named after him. He was also known for the first telescope, discovered sunspots, stars not fixed to celestial sphere and Venus goes through phases similar to moon.

Reflecting Telescope

1668

Reflecting Telescope- This telescope uses a single or combination of curved mirrors that reflect light and form an image. Reflecting telescopes are more useful than refracting telescopes, because chromatic aberration is not an issue, and they have a significantly larger range than refractors.

Giovanni Cassini

1712

Cassini- He was an Italian mathematician who was first to observe the rings of Saturn and the four moons of Saturn. Cassini also discovered the rotation periods for mars and Jupiter.

Sir Isaac Newton

1727

Newton- He was an English mathematician and physicist. He developed a reflecting telescope and the 3 laws of motion. He worked with Copernicus and Kepler using math.

William Herschel

1822

Herschel- Discovered the planet Uranus and its moons. He determined the temperature of colors with prisms. He realized the red color was even higher than light in visible spectrum.

Percival Lowell

1916

Lowell- An American astronomer who predicted the existence of a planet beyond the orbit of Neptune called Pluto. He studied the “canals” on mars. The observatory is in Flagstaff AZ.

Karl Jansky

1950

Jansky- Karl Guthe Jansky was an American physicist and radio engineer who first discovered radio waves emanating from the Milky Way. He found the radio astronomy.

Edwin Hubble

1953

Hubble- Edwin Powell Hubble was an American astronomer who used the color of the stars to discover that the universe is expanding. His idea is the basis of the big bang theory of how the universe begin.

Albert Einstein

1955

Albert Einstein- Developed the theory of relativity, which is one of the two pillars in modern physics. His work helped for it influence on the philosophy of science.

Sputnik

1957

Sputnik- The sputnik is the first artificial Earth satellite. Which also got launched to a elliptical low Earth orbit. The launch of Sputnik served to increase the arms race and raise Cold War tensions. Science and space travel became a huge priority to the US because Russia was successful with their first spacecraft, putting them better in the lead, but the creation of NASA was born to move on.

Yuri Gagarin

1961

Gagarin- Russian cosmonaut Yuri Gagarin became the first person to travel into space. He was launched on the onto the Vostok 3KA-3 spacecraft in 108 minutes.

John Glenn

1962

Glenn- He became the first American to orbit the earth, circling it 3 times.

Ejnar Hertzsprung

1967

Hertzsprung- He was a Danish chemist who worked with Henry Norris Russell and was one of the inventors of the Russell diagram. The diagram showed the correlation and brightness of the stars.

Neil Armstrong

1969

Neil Armstrong- ) He was the first American to walk on the moon. Apollo 11 was the spaceflight that landed the first two humans on the moon. Neil Armstrong and Buzz Aldrin, both American landed the lunar module eagle on July 20, 1969.

Apollo Missions

1975

Apollo Missions- This was the third US human spaceflight program carried out by the National Aeronautics and Space Administration, which succeeded in landing humans on moon and bringing them back.

First space shuttle flight

1981

First space shuttle flight- the first space shuttle was called space shuttle Columbia, which was the first reusable spacecraft. It launched like a rocket and lands like a plane.

Mars Pathfinder Expedition

1997

Mars Pathfinder Expedition- A American robotic spacecraft that landed a base station with a roving probe on mars.

SpaceX Falcon Heavy

2012

SpaceX Falcon Heavy- Falcon Heavy is a reusable heavy-lift launch vehicle designed and manufactured by SpaceX. The first flight was in 2010, the second was in 2012 and the third was in 2012 along with the fourth one.

Cassini Orbiter

2017

Cassini Orbiter-It's called the Cassini because it was a collaboration between NASA and Italian space agency. This was a probe to study Saturn and its system. This means including its rings and natural satellites.