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Astronomers. Claudius Ptolemy. about 85 - about 165 One of the most influential Greek astronomers and geographers of his time Discovered that there were 365 ¼ days in a year Observed and wrote about solstices and equinoxes defining the lengths of seasons . Nicolaus Copernicus.
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Claudius Ptolemy • about 85 - about 165 • One of the most influential Greek astronomers and geographers of his time • Discovered that there were 365 ¼ days in a year • Observed and wrote about solstices and equinoxes defining the lengths of seasons
Nicolaus Copernicus • February 1473-1543 • Polish astronomer and mathematician • First noticed that the Earth spins on an axis and that the Earth revolves around the Sun. • This hypothesis was rejected church.
Tycho Brahe • 1546 - 1601 • Danish astronomer • His theory of the solar system is based on a stationary Earth round which the Moon and Sun revolve. • The other planets, according to Tycho's theory, revolve round the Sun. • Hypothesized that the scale of the universe was unbelievably large
Galileo Galilei • 1564 – 1642 • Italian scientist who formulated the basic law of falling bodies • Italian scientist who constructed a telescope with which he studied lunar craters, and discovered four moons revolving around Jupiter • First observed Saturn, Neptune and sun spots
Johannes Kepler • 1571 - 1630 • German mathematician and astronomer who discovered that the Earth and planets travel about the sun in elliptical orbits • Discovered Supernova 1604
EjnarHertzsprung • 1873 – 1967 • Danish chemist and astronomer • His greatest contribution to astronomy was the development of a classification system for stars to divide them by spectral type, stage in their development, and luminosity called "Hertzsprung–Russell Diagram“.
Edwin Powell Hubble • 1889 - 1953 • American astronomer who first detected that the universe is expanding. • He showed that galaxies are moving away from us with a speed proportional to their distance. • In 1924 Hubble measured the distance to the Andromeda nebula and discovered that it had to be a separate galaxy, comparable in size our own Milky Way but much further away.
Gerard P. Kuiper • 1905 – 1973 • Netherlands-born American Scientists • Discovered twonatural satellitesofplanets in the solar system, namely Uranus's satellite Miranda and Neptune's satellite Nereid. • Astronomers refer to a region of small planets beyond Neptune as the "Kuiper belt", since Kuiper had suggested that such small planets or comets may have formed there.
Stephen Hawking • 1942 - • an Englishtheoretical physicist and cosmologist • Created the framework ofgeneral relativity and the theoretical prediction thatblack holes emit radiation, now known as Hawking Radiation.