# Kai-Thomas_history of astronomy

• Period: 400 BCE to

• 384 BCE

# Aristotle

Aristotle, also known as the Grandfather of Science, was a Greek philosopher born 384 BC. Aristotle was taught by Plato, and later opened up his own school. Aristotle believed in a geocentric system that all celestial bodies were perfect spheres, except for earth.
• 100

# Ptolemy

Ptolemy was an astronomer and mathematician born in 100 AD and Died in 168. like Aristotle he believed in a Geocentric system, meaning earth was at the center of the solar system. Ptolemy used math to predict the movement of planets and stars.
• 1473

# Copernicus

Nicolas Copernicus was born 1473 and died in 1543. Copernicus believed in a heliocentric system meaning the sun was in the middle.
• 1546

# Tycho Brahe

Tycho Brahe was born in 1546 and died in 1601. Tycho Brahe constructed instruments used to measure star positions. His predictions were the most accurate before the telescope.
• 1564

# Galileo

Galileo was born in 1564 and died in 1630. Galileo Galilee created a version of the telescope which could magnify objects up to 20 times larger. he was able to prove the theory of a heliocentric solar system.
• 1571

# Johannes Kepler

Johannes Kepler was born in 1571 and died in 1630. Kepler discovered the laws of planetary motion. The first law was that the planets orbited the sun in an elliptical or oval motion. The second law was that the time it took to travel any arc of planetary orbit, is proportional the the are between that ark and the central body. the third and final law states "there is an exact relationship between the squares of the planets’ periodic times and the cubes of the radii of their orbits."
• # Difference between refracting and reflecting telescopes

The refracting telescope was invented in 1608. It gathers the light coming from a distant object, like a star, and bends it into a single point if focus. Another lens job is to enlarge that focused image for our eye, it acts as a magnifying glass. The reflecting telescope invented in 1668, gathers Light from an object and directs it into the telescope and it is reflected off a curved mirror at the end of the tube. A second, mirror in the middle of the tube reflects this image to the eyepiece.
• # Hans Lippershey

Hans Lippershey was born in 1570 and died in 1619. Lippershey is credited with inventing the telescope.
• # Giovanni Cassini

Giovanni Cassini was born was born in 1625 and died in 1712. Cassini discovered some of Saturn's moons such as Dione, Rhea, and Tethys. He also discovered the diurnal rotation of Venus.
• # Sir Issac Newton

Issac Newton was born in 1643 and died in 1724. Issac Newton discovered the laws of motion and gravity. In 1705 queen Anne knighted him gaining him the title of sir
• # Sir William Herschel

William Herschel was born in 1738 and died in 1822. Herschel founded sidereal astronomy and discovered Uranus. Sidereal astronomy measures earths rotation relative to the stars rather than the sun. He was knighted in 1816
• # Percival Lowell

Percival Lowell was born in 1855 and died in 1916. Lowell predicted that a planet was beyond Neptune, this led to the discovery of Pluto.
• # Ejnar Hertzsprung

Ejnar Hertzsprung was born in 1873 and died in 1967. Hertzsprung classified by their color and absolute brightness. he also invented the luminosity scale of Cepheid variable stars.
• # Albert Einstein

Albert Einstein was born in 1879 and died 1955. Einstein developed the theory's of relativity. the laws of physics are the same for all non-accelerating observers, and he showed that the speed of light within a vacuum is the same no matter the speed at which an observer travels. Energy Equals mass multiplied by the speed of light squared (e=mc2)
• # Edwin Hubble

Edwin Hubble was born in 1889 and died in 1953. Hubble observed that the universe is ever expanding and there are more galaxies beyond the milky way.
• # Karl Jansky

Karl Jansky was born in 1905 and died in 1950. Jansky discovered radio waves from an external source integrated the development of radio astronomy. this extended the capacity and reach of astronomical observation
• # Sputnik

Sputnik was the first satellite, it was launched by the soviet union in 1957. People were terrified that a nuclear bomb was on board because radios picked up a beeping noise being transmitted from it. The satellite circled the Earth in 96 minutes. Its speed was about 18,000 miles per hour. The satellite orbited the earth for 3 weeks before its batteries died.
• # Yuri Gagarin

Yuri Gagarin was born in 1934 and died in 1968. Gagarin was a Russian cosmonaut and was the first person in space. The flight lasted 108 minutes.
• # John Glenn

John Glenn was born in 1921 and died in 2016. Glenn was the first American in space, he orbited the Earth 3 times.
• # The Apollo Program

The Apollo program was a project conducted by the united states, from 1963 to 1972. President John F Kennedy challenged the nation to land on the moon by the end of the decade(1970). The Apollo 11 landed on the moon in 1969.
• # Neil Armstrong

Neil Armstrong was born in 1930 and died in 2012. Armstrong was the first man on the moon during the Apollo 11 expedition. his famous saying was " One small step for man, One giant leap for man kind."
• # First Shuttle Flight

The first space shuttle was originally called the space transportation system. The program started in 1981 and ended 2011. It It was composed of a reusable rocket and 2 thrusters that detached.
• # Mars Pathfinder Expedition

A probe was launched to mars to observe the planet and demonstrate a new way to land on a planets surface. Scientists were able to conclude from the data gathered by the probe that it was once much like earth.
• # Cassini orbiter

The Cassini orbiter was sent into space equipped with powerful instruments and cameras to take measurements and pictures of Saturn and its moons specifically Titan. In July 2004 the probe landed on Titan.
• # Saturn is losing its rings

Saturn is losing its rings by a phenomenon called ring rain. This process pulls the water vapor in Saturn's rings out into the planets atmosphere. scientist estimate the rings may be gone in the next 300 million years or even faster.