11

F.D.G.s # 4 & 5F.D.G.s # 4 & 5

(Famous Dead Guys # 4 & 5)(Famous Dead Guys # 4 & 5)

Copernicus and GalileoCopernicus and Galileo

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Nicholas Copernicus Nicholas Copernicus (Feb. 19, 1473- May 24, 1543)(Feb. 19, 1473- May 24, 1543)

Became unhappy with Ptolemy’stheory for the motions of the planets

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Copernicus’ heliocentric Solar Copernicus’ heliocentric Solar SystemSystem

All of the planets goaround the sun, althoughthe moon does go aroundthe earth

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Heliocentric ModelHeliocentric Model

Heliocentric Heliocentric model = Sun model = Sun centered centered UniverseUniverse

55

Retrograde motion in an easy to Retrograde motion in an easy to assemble package!assemble package!

Copernicus’ Copernicus’ model could more model could more easily explain the easily explain the motion of the motion of the planets than could planets than could Ptolemy, with Ptolemy, with less complexity.less complexity.

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We don’t need no stinkin’ wheels!We don’t need no stinkin’ wheels!

Copernicus’ model didn’t require complex Copernicus’ model didn’t require complex epicycles like Ptolemy’s did.epicycles like Ptolemy’s did.

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Time to publish…Time to publish…

De revolutionibus De revolutionibus orbium coelestiumorbium coelestium– ““On the revolutions of On the revolutions of

the celestial the celestial (Heavenly) spheres”(Heavenly) spheres”

88

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Copernicus’ ModelCopernicus’ Model

Figured the length of Figured the length of time the planets take time the planets take to orbit the sun from to orbit the sun from observations of how observations of how long they take to re-long they take to re-appear at the same appear at the same place in the night skyplace in the night sky– Also figured out the Also figured out the

distances to the distances to the planetsplanets

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Copernicus’ Model cont…Copernicus’ Model cont…

The Earth’s center is not the center of the The Earth’s center is not the center of the UniverseUniverse– Religion?Religion?

The center of the Universe is near the SunThe center of the Universe is near the Sun

The rotation of the Earth accounts for the The rotation of the Earth accounts for the apparent daily rotation of the starsapparent daily rotation of the stars

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Copernicus’ Model cont…Copernicus’ Model cont…

The annual The annual movements of the movements of the Sun are caused by Sun are caused by the Earth revolving the Earth revolving around it, not the Sun around it, not the Sun moving around the moving around the Earth.Earth.

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Copernicus’ Model cont…Copernicus’ Model cont…

Retrograde motion of Retrograde motion of the planets is caused the planets is caused by the motion of the by the motion of the Earth, from which we Earth, from which we (on the Earth) (on the Earth) observe itobserve it

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How good was Copernicus’s model?How good was Copernicus’s model?

He could not really predict the motions of He could not really predict the motions of the planets in the sky more accurately the planets in the sky more accurately than Ptolemy because he stuck with the than Ptolemy because he stuck with the idea of uniform circular motionidea of uniform circular motion– Needed Kepler’s helpNeeded Kepler’s help

Thus he couldn’t entirely get rid of Thus he couldn’t entirely get rid of epicyclesepicycles

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F.D.G – Galileo Galilei (1564 – F.D.G – Galileo Galilei (1564 – 1642)1642)

Father of modern observational astronomyFather of modern observational astronomy

1515

Galileo GalileiGalileo Galilei

First to use a telescope First to use a telescope for observational for observational astronomyastronomy– C.S.M. He C.S.M. He DID NOTDID NOT invent invent

the telescope, rather he the telescope, rather he was the first to use it was the first to use it extensively for extensively for astronomical observations.astronomical observations.

1616

Galileo GalileiGalileo Galilei

Published his Published his acceptance of acceptance of Copernicus’ theory of Copernicus’ theory of the Universethe Universe

Described views of Described views of the moon with the moon with mountains, craters mountains, craters and dark lunar “seas”and dark lunar “seas”

1717

Galileo GalileiGalileo Galilei

Discovered moons of Discovered moons of JupiterJupiter– Proved not all objects Proved not all objects

revolve around the revolve around the EarthEarth

1818

Galilean MoonsGalilean Moons– (In order of distance from (In order of distance from

Jupiter: Io (the most Jupiter: Io (the most volcanically active body in volcanically active body in the solar system), Europa the solar system), Europa (suspected to contain a (suspected to contain a liquid ocean under its liquid ocean under its frozen surface), Ganymede frozen surface), Ganymede (the largest satellite in the (the largest satellite in the solar system), and Callisto. solar system), and Callisto. Both Ganymede and Both Ganymede and Callisto are larger than Callisto are larger than Pluto and Mercury. )Pluto and Mercury. )

1919

Galileo and VenusGalileo and Venus

Discovered that Venus has phases, just Discovered that Venus has phases, just like our own moonlike our own moon

2020

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Galileo as an AuthorGalileo as an Author

Published Published Dialogue Dialogue on the Two Great on the Two Great World SystemsWorld Systems as a as a dialogue between two dialogue between two philosophers philosophers supporting supporting Copernicus, and a Copernicus, and a layman supporting layman supporting PtolemyPtolemy

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Busted!!!Busted!!!

Called before Inquisition in 1632, where Called before Inquisition in 1632, where the book was condemmedthe book was condemmed

Galileo sentenced to house arrest for the Galileo sentenced to house arrest for the rest of his liferest of his life

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R.I.P.R.I.P.

Died in 1642Died in 1642

Buried in Florence, Buried in Florence, ItalyItaly

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Geo vs. HelioGeo vs. Helio

Geo Helio