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150
ptolemy
Roman citizen living in Egypt Came up with system of Earth as center = ptolemaic system -
Feb 12, 1543
Copernicus published around...
wrote in lating = not for the masses
Heliocentric system Challenged aristotle! Learned astronomy himself thansk to printing press!!!! -
Feb 12, 1572
Tyco Brahe's stella nova
-Bright enough to be seen during the day
-"New star" = challenge to Aristotle's unchanging skies. -
Feb 12, 1577
Tyco Brahe spots a comet - no parallax!
So comet very close - would have smashed through crystalline spheres -
William Gilbert (1544 - 1603) qualitative experiments on electricity
Inspired Galileo -
Kepler's laws of planetary motion
- orbits are ellipses
- Planets speed up as they approach the sun and slow down as they move away
- Orbital speed drops as the orbital length increases
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Thomas Harriot uses telescope to look at ngiht sky BUT silent!
he doesn't tell anyone = no credit! no impact! Did so MONTHS before Galileo -
Galileo's Starry Messenger
In january of 1610, turns telescope to the sky ! -
"letter to the Grand duchess Chistina" by Galileo
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Copernicus placed on index of banned books
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Period: to
Cooling off period for Galileo and the Church
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Galileo writes "dialogue concerning the two chief world systems
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Royal Society of London created
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Newton "discovers" gravity, invents calculus and theory of light
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Paris Academy of Sciences created
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Royal Soc of London elects Newton as Fellow bc of mirror telescope
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William Hershel Discovers Uranus
New planets! Expanded the size of the solar system Also discoveres its moons -
1840s first photographs of the moon
Could be linked with spectroscopy -
Helium discovered by Lockyer and Janssen
lines not seen in the spectrum of any element tested = new elements in the Sun! -
Joseph von Fraunhofer observes spectral absorption in solar spectrum
coudl determine what was in the sun Spectroscopy as a way to classify stars bsed on what elements they contain. -
henrietta Leavitt's Cepheids - standard candle
She discovered 4 new stars AND variable stars = Cepheids! (standard candle = relationshi bw brightness and period, If you move candle away - less bright! so you can figure out how far away the star is) -
Hubble announces that universe is a lot bigger than we thought.
Using Cepheids he identified in spiral nebulae- universe is expanding = 1931
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Big bang idea proposed by George Lemaitre
evidence only foundn in 1964 bc of cosmic radiation -
Dark matter by Fritz "missing mass"
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Dark Energy as reason for universe expansion speeding up