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Democritus (460 BCE - 370 BCE)
He is attributed with the atomic theory of the universe, which was developed by a Greek philosopher names Leucippus. This theory explained that the world is composed of indivisible particles of matter throughout the empty space. Atoms had not only shape but mass and motion as well. Lastly, he believed cosmos form from spinning vortexes of atoms. -
Aristotle (384 BCE - 322 BCE)
He believed the universe was spherical and completely finite. He used observations of lunar eclipses to support his theories of earth and the universe. Aristotle also believed in a fifth element called “aether” which was to be considered the make up of celestial bodies. He influenced medieval scholars as well as others in his hierarchical model of the universe. -
Eratosthenes (276 BCE - 196 BCE)
He was a Greek astronomer as well as a mathematician, poet, and georgrapher. Today, he can also be credited with measuring Earth's circumferance and creating a calender including leap years. -
Hipparchus (190 BCE - 120 BCE)
Not only was he known for being an esteemed astronomer but an important mathematician too. He calculated the length of the year and created a star chart with 850 stars included. His most influential discovery was of the precession, which is caused by the slow change in direction of the axis rotation of the Earth. -
Abd Al-Rahman Al Sufi (903 - 986)
He was a Persian astronomer who documented the Andromeda galaxy and called it the “little cloud”. This can be considered the first record of a star system outside Earth’s own galaxy. He also wrote a book called Kitah al Kawaatib. -
Copernicus (1473 - 1543)
Copernicus was a Polish astronomer who proposed that the Earth not only orbited the Sun annually but turns daily on its own axis as well. He considered this to be called the precession of the equinoxes. This representation of the heavens can be called heliocentric. -
Galileo (1564 - 1642)
Galileo was an Italian astronomer and physicist. In 1609, Galileo used math and the new invention of the spyglass to create a telescope. In the very same year he became the first person to look at the moon through a telescope; he identified the moon was not at all smooth but instead pitted and mountainous. He also discovered moons around Jupiter as well as other things. -
Sir Isaac Newton (1643-1727)
He has been considered one of the greatest scientific genius of all time. in 1684, Netwon visited Edmond Halley and discussed the problem of orbital motion. His most significant acomplishment was his work in physics and celestial mechanics which resulted in the theory of universal gravitation along with the three laws of motion. -
- Edmond Halley (1656-1742)
He was an English astronomer, which was credited in the discovery of the proper motion of stars and the periodicity of comets. He also observed a transit of Mercury and catalogued 350 Southern Hemisphere stars’ positions. -
Sir William Herschel (1738-1822)
Sir William Herschel was an English astronomer who built high magnification telescopes to observe the heavans in great detail. While working on an extension of his double star catalogue, he saw an area around the star H Geminorum where there had no evidence proir of stars. He later discovered it was the planet Uranus. -
Williamina Fleming (1857-1911)
She was the first to discover white dwarf stars as well as develop a system of classifiying stars according to their spectra. With this system, she was able to catagorize ten thousand stars. -
Albert Einstein (1879-1955)
In 1905, Einstein began developing the Theory of Relativivity. After completing this theory ten years later, a solar eclipse in 1919 proved it was true. He won a Nobel Prize in physics in 1921. -
Robert H. Goddard (1882-1945)
Goddard was an American known for being one of the founding fathers of modern rocket propulsion. in 1926, he desigined, built, and launched the word's first liquid fueled rocket. -
Clyde Tombaugh (1906-1997)
Clyde Tombaugh was an American astronomer who discovered the planet Pluto. He was hired as a junior astronomer to locate Planet X in 1929 and on March 30, 1930 his discovery was confirmed. -
Stephen Hawking (1942-)
Hawkings was diagnosed with Lou Gehrigs disease in 1962. However, upon completion of his doctorate in 1966, he was awarded a fellowship at Gonville and Caius College, Cambridge. Hawking has held the Lucasian professorship in mathematics since 1979; which was held by Sir Isaac Netwon three hundred years prior.
