• 200

# Aristotle

(384 BC - 322 BC) -Argued that universe was spherical because it was the most perfect shape, and finite because it had a center (the earth). -Believed the earth was a sphere and was at rest. Information: http://library.thinkquest.org/18775/aristotle/bioar.htm
http://perseus.mpiwg-berlin.mpg.de/GreekScience/Students/Tom/AristotleAstro.html
Picture: http://mrsvesseymathematicians.wikispaces.com/Aristotle
• 200

# Aristarchus of Samos

(310 BC - 230 BC) -Believed the sun was the center of the universe (this idea was not well recieved) -Calculated the the diameter of the sun to be 7 times the diameter of the earth (actual diamter is 300 times the diameter of earth). -Calculated the volume of the sun to be 300 times the volume of earth (actual volume is 1,300,00 times the volume of earth) Information: http://www.varchive.org/ce/orbit/arisam.htm
Picture: http://learn.tsinghua.edu.cn:8080/2005012177/topic.html
• 200

# Eratosthenes

(276 BC - 194 BC) -Made a surprisingly accurate measurement of the Earth's circumference by comparing noon time shadows in diferent locations. -Calculated the distances to the moon and the sun, and calculated the tilt of earth's axis. Information & Picture: http://www-groups.dcs.st-and.ac.uk/~history/Biographies/Eratosthenes.html
• 200

# Hipparchus

(190 - 120) -Measured the distance to the moon during a solar eclipes by comparing how much of the sun was seen in another location and using that angle to determine the distance to the moon. -Created the 1st accurate star map and catalogued over 850 stars and with their relative brightness. Information: http://www.astro.cornell.edu/academics/courses/astro201/hipparchus.htm
Information & Picture: http://www.windows2universe.org/people/ancient_epoch/hipparchus.html
• 200

# Pythagoras

(569 BC - 475 BC) -Recognised that the orbit of the Moon was inclined to the equator of the Earth. -Realised that the evening star Venus was the same planet as the morning star Venus. -Believed the earth was a sphere because it was the most perfect shape. Information: http://www-history.mcs.st-and.ac.uk/HistTopics/Greek_astronomy.html
Picture: http://www.stenudd.com/myth/greek/pythagoras.htm
• 200

# Ancient Greek Astronomy

(700 BC - 300 AD) -Involved more math than physics and therefore was concidered a branch of mathematics. -Astronomy was about time keeping. Events, such as the day would make a natural period of time and likewise the periodic phases of the moon made the next natural time span. -Many times philosophers came up with ideas about the universe which were not based on the scientific method. Information: http://www-history.mcs.st-and.ac.uk/HistTopics/Greek_astronomy.html
• Jan 1, 1473

# Copernicus

(1473 - 1543) -Supported the idea of a heliocentric (sun centered) universe, thought the universe was much larger than previously believed. -Believed the earth was orbited by the moon and nothing else, and that the apparent motion of the sun and other heavenly bodies was created by the motion of earth. Information: http://plato.stanford.edu/entries/copernicus/
Picture: http://www.oceanparkoes.org/study/?p=88
• Dec 14, 1546

# Tycho Brahe

(1546 - 1601) -Constructed a quadrant which was very accurate but was so big it required many servants to align, so only one observation could be made each night. -Made observations of a new star in the costellation Casiopeia. The star is now usually known as 'Tycho's supernova'. Information & Picture: http://www-history.mcs.st-and.ac.uk/Biographies/Brahe.html
• Feb 15, 1564

# Galileo Galilei

(1564 - 1642) -Discovered the moons of Jupiter, and the phases of Venus. -Constructed a telescope superior to many othes at that time. -Due to observation made with his new telescope he supported Copernicus' theory of a helicentric universe. Information & Picture: http://www.lucidcafe.com/library/96feb/galileo.html
• Dec 27, 1571

# Johannes Kepler

(1571 - 1630) -Theorized that the orbit of the planets could determined by using an equilateral triangle to find the fixed ratio between different circles. -Devised three planetary laws concerning the orbits of planets. -Studied the harmonic proporties of planetary motion. Information: http://www.johanneskepler.com/johannes_kepler_bio_003.htm
Picture: http://www.thocp.net/biographies/kepler_johannes.htm
• # Isaac Newton

(1642 - 1727) -Calculated the force needed to hold the moon in its orbit, compared with a force pulling an object towards the ground. -Identified gravitation as the fundamental force that controlled the movement of planets in space. He also alculated the relative masses of planets from their gravitational forces. -Explained that the tides and the equinoxes were from the forces exerted by the sun and moon. Information & Picture: http://www.newton.ac.uk/newtlife.html
• # Annie Jump Cannon

(1863 - 1941) -Measured and cataloged the optical spectra of stars. -Derived a simplified classification system for star spectra. Information: http://www.sdsc.edu/ScienceWomen/cannon.html
Picture: http://en.wikipedia.org/wiki/Annie_Jump_Cannon
• # George Hale

(1868 - 1938) -Founder of Mt. Wilson Observatory. -Helped build a 200 inch telescope which was named the Hale telescope in honor of him. -Invented the spectroheliograph which was used to photograph the sun. Information & Picture: http://www.mwoa.org/hale.html
Information: http://scienceworld.wolfram.com/biography/Hale.html
• # Henrietta Swan Leavitt

(1868 -1921) -Came up with a system to determine the magnitude of stars by using “the north polar sequence” as a gage of brightness. It was adopted by the International Committee on Photographic Magnitudes -Discovered over 1,200 variable stars. -Determined the absolute magnitudes of stars, which in turn led to the ability to determine distances of stars. Information: http://www.womanastronomer.com/hleavitt.htm
Picture: http://www.famousscientists.org/henrietta-swan-leavitt/
• # Albert Einstein

(1879 - 1955) -Developed quantum theory and the theory of relativity. -Investigated the thermal properties of light with a low radiation density which lead to the foundation of the photon theory of light. Information: http://nobelprize.org/nobel_prizes/physics/laureates/1921/einstein-bio.html
Picture: http://www.myanmars.net/myanmar-history/albert-einstein-quote.htm
• # Edwin Hubble

(1889 - 1953) -Determined the existence of several galaxies such as our own milky way. -Formulated Hubble's Law which helped astronomers determine the age of the universe, and proved that the universe was expanding. -He was instrumental in the design of the Hale Telescope -Hubble Telescope was named after him because of his important discoveries. Information: http://hubblesite.org/the_telescope/hubble_essentials/edwin_hub
Information & Picture: http://www.edwinhubble.com/hubble_bio_001.htm
• # Gerard Kuiper

(1905 - 1973) -Considered the father of modern planitary science. -Discovered the Kuiper Belt which is a disk-shaped region of minor planets outside the orbit of Neptune that is a source of short-period comets. -Was the chief scientist for the Ranger lunar probe program, and was responsible for choosing landing crash sites on the moon by analysing of Ranger photographs. -He helped identify landing sites for the Surveyor and Apollo Programs. Information & Picture: http://www.nnp.org/nni/Pub
• # Bengt Georg Daniel Stromgren

(1908 - 1987) -Hipothesized about Stromgren Spheres. zones of ionized hydrogen gas surrounding hot stars embedded in gas clouds (key to our understanding of the structure of interstellar material). -Proposed that the light from luminous nebulae was caused by hot stars within obscuring layers of gas. Information: http://encyclopedia.farlex.com/StrÃ¶mgren,+Bengt+Georg+Daniel
Picture: http://pl.wikipedia.org/wiki/Portal:Astronomia/Sylwetka_10_2009

(1910 - 1995) -Studied stellar structures, including the theory of white dwarfs. -Showed that a star with a mass greater than 1.4 times that of the Sun (now known as the Chandrasekhar's limit) had to end by collapsing into an object of enormous density unlike any object known at that time. -Researched the mathematical theory of black holes. Information & Picture: http://www-groups.dcs.st-and.ac.uk/~history/Biographies/Chandrasekhar.html
• # Grote Reber

(1911 - 2002) -Built a radio telescope in his backyard. -Used telescope to detect radio emissions from the Milky Way Galaxy. -Used this information to produce contour maps of the Milky Way. Information & Picture: http://www.nrao.edu/whatisra/hist_reber.shtml
• # James Van Allen

(1914 - 2006) -Discovered the radiation belt around Earth which is now called the Van Allen Belt. -Helped develop a small, efficient rocket, which could be launched from a high altitude balloon. It became known as the “Rockoon”. Information & Picture: http://www.nnp.org/nni/Publications/Dutch-American/vanallenj.html
• # Sir Fred Hoyle

(1915 - 2001) -Rejected 'big bang' theory because he thought it could not have taken place unless space and time already existed. He propose a 'steady-state' universe in which matter is continually generated by some unknown mechanism. -Established the Institute of Theoretical Astronomy at Cambridge University. Information & Picture: http://physicsworld.com/cws/article/news/2615
• # E. Margaret Burbidge

(1919 - present) -Studied the spectra of galaxies and nuclear reactions at the center of stars -Improved the explanation of how elements are formed by nuclear reactions inside stars. -Developed intsrumentation for the Hubble Telescope. Information & Picture: http://www.nndb.com/people/692/000168188/
• # Eugene Shoemaker

(1928 - 1997) -Conducted research on the mechanics of meteorite impacts. -Had a leading role in the study of "astrogeology". -Organized the geological activities planned for the lunar landings. Information: http://www2.jpl.nasa.gov/sl9/news81.html
Picture: http://www.scienceclarified.com/scitech/Comets-and-Asteroids/When-Comets-and-Asteroids-Strike-Earth.html
• # Thomas Mutch

(1931 - 1980) -Led the Lander Imaging Team for the Viking Mission to Mars. -Is the author of "The Geology of the Moon: Startigraphic View", and the co-author of "The Geology of Mars." -Taught planetary geology at Brown University. Information & Picture: http://www.brown.edu/Departments/Geology/colloquia/mutch.html