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
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
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
Based on observations NOT authority!
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
Copernicus placed on index of banned books
Cooling off period for Galileo and the Church
Galileo writes "dialogue concerning the two chief world systems
Royal Society of London created
Newton "discovers" gravity, invents calculus and theory of light
Paris Academy of Sciences created
Royal Soc of London elects Newton as Fellow bc of mirror telescope
William Hershel Discovers Uranus
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
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
Big bang idea proposed by George Lemaitre
evidence only foundn in 1964 bc of cosmic radiation
Dark matter by Fritz "missing mass"
Dark Energy as reason for universe expansion speeding up