Transcript Copernicus and Galileo

F.D.G.s # 4 & 5
(Famous Dead Guys # 4 & 5)
Copernicus and Galileo
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Nicholas Copernicus
(Feb. 19, 1473- May 24, 1543)
Became unhappy with Ptolemy’s
theory for the motions of the planets
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Copernicus’ heliocentric Solar
System
All of the planets go
around the sun, although
the moon does go around
the earth
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Heliocentric Model
Heliocentric
model = Sun
centered
Universe
4
Retrograde motion in an easy to
assemble package!
Copernicus’ model
could more easily
explain the motion
of the planets than
could Ptolemy,
with less
complexity.
5
We don’t need no stinkin’ wheels!
Copernicus’ model didn’t require complex
epicycles like Ptolemy’s did.
6
Time to publish…
De revolutionibus
orbium coelestium
– “On the revolutions of
the celestial
(Heavenly) spheres”
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Copernicus’ Model
Figured the length of
time the planets take
to orbit the sun from
observations of how
long they take to reappear at the same
place in the night sky
– Also figured out the
distances to the
planets
9
Copernicus’ Model cont…
The Earth’s center is not the center of the
Universe
– Religion?
The center of the Universe is near the Sun
The rotation of the Earth accounts for the
apparent daily rotation of the stars
10
Copernicus’ Model cont…
The annual
movements of the
Sun are caused by
the Earth revolving
around it, not the Sun
moving around the
Earth.
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Copernicus’ Model cont…
Retrograde motion of
the planets is caused
by the motion of the
Earth, from which we
(on the Earth)
observe it
12
How good was Copernicus’s model?
He could not really predict the motions of
the planets in the sky more accurately
than Ptolemy because he stuck with the
idea of uniform circular motion
– Needed Kepler’s help
Thus he couldn’t entirely get rid of
epicycles
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F.D.G – Galileo Galilei (1564 –
1642)
Father of modern observational astronomy
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Galileo Galilei
First to use a telescope
for observational
astronomy
– C.S.M. He DID NOT invent
the telescope, rather he
was the first to use it
extensively for
astronomical observations.
15
Galileo Galilei
Published his
acceptance of
Copernicus’ theory of
the Universe
Described views of
the moon with
mountains, craters
and dark lunar “seas”
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Galileo Galilei
Discovered moons of
Jupiter
– Proved not all objects
revolve around the
Earth
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Galilean Moons
– (In order of distance from
Jupiter: Io (the most
volcanically active body in
the solar system), Europa
(suspected to contain a
liquid ocean under its
frozen surface), Ganymede
(the largest satellite in the
solar system), and Callisto.
Both Ganymede and
Callisto are larger than
Pluto and Mercury. )
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Galileo and Venus
Discovered that Venus has phases, just
like our own moon
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Galileo as an Author
Published Dialogue
on the Two Great
World Systems as a
dialogue between two
philosophers
supporting
Copernicus, and a
layman supporting
Ptolemy
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Busted!!!
Called before Inquisition in 1632, where
the book was condemmed
Galileo sentenced to house arrest for the
rest of his life
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R.I.P.
Died in 1642
Buried in Florence,
Italy
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Geo vs. Helio
Geo
Helio
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