Transcript Document

Kepler’s Laws
2/18/1996
…lots and lots and lots of math.
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Goal
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Is astrology a science?
Why should we care?
Kepler: Astrologer turned Astronomer.
Kepler’s Laws.
Proof of Kepler’s Laws.
Planets around other stars.
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Recap
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Science is about making theories.
Scientific theories:
– Explain what is already seen
– Predict what can be seen in the future.
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Predictions can be falsified.
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Astrology
• The date, time, (and place) of birth affect:
– Your personality
– Your actions
– Events that will affect your life
• Horoscopes appear in most papers.
• Millions of people read them daily.
http://www.azcentral.com/ent/horoscopes/astrology101.html
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Astrology
• Is it a science?
– Explain what is seen?
– Make predictions?
• Does it work?
• What test would falsify astrology?
• Does it matter?
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Astrology and the President
(TIME, May
16, 1988)
-- Chief of Staff, Donald] Regan and
“[Former
White
House
“The First
Lady
dabbled in astrology
as far
others
make
a compelling
case that
inback
1986 and 1987
as 1967. In 1981
[Joan] Quigley
made Nancy
a
astrological
influence
dramatically
reduced
the
believer …. And from then on, no presidential
presidency's
effectiveness, at least partly, by keeping
public appearance was slated without the
Ronald
wraps
forFriend
much of the time.
Friend's Reagan
say-so. Tounder
this day,
Nancy's
Nancy's
scheduling
process, Regan said
continuesintrusions
to influencein
thethe
President's
schedule.
Reagan-Gorbachev
Washington
summit,
inFor
anthe
interview
with TIME
last week,
‘began to interfere
she cast
charts conduct
of both men
with
thethe
normal
ofand
thedetermined
presidency.’”
that 2 p.m. on Dec. 8, 1987, was the most propitious moment for
(TIME,
Maythe16,
1988)
them to sign
intermediate-range
nuclear forces treaty. At
Nancy's behest, the entire summit was built around that hour. For
the upcoming Moscow summit, Gorbachev's chart (he is a Pisces)
has been recast alongside Reagan's (Aquarius).”
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It Works
Courtesy NASA/JPL/Cornell
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Mars
Courtesy NASA/JPL/Cornell
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Orbital Mechanics
Courtesy David Crisp and WFPC2 Science Team
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Kepler’s Laws
1. Orbits are always
ellipses.
2. Sweep out equal areas
in equal times.
3. The period of orbit is
related to average
separation.
Period  Separation
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Astrology to Astronomy
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Kepler was an astrologer.
Looked for Perfect Solids
Wants did not match with Observations (tests).
Followed the facts where they led.
The result works.
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Class Structure
Investigate 4 Key Topics this semester:
1. Extrasolar Planets
2. Black Holes
3. The Big Bang
4. SETI
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Class Structure
• During each topic:
– Pieces in a puzzle.
– Many pieces in several topics
• At the end of each topic:
–
–
–
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See how pieces fit.
See how the scientific method is applied
What is the evidence
Have a test.
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Homework #3
• For Lab this week:
• Read Bennett chapter 1.1 – 1.2
– (B1.1 – 1.2 on Physics 103 lecture web page)
• For Thursday 1/22:
• Read Ty7, Ty8, B6.1 – 6.3
• Do B6: Problems 1, 2, 3, 7, 15
– (PHYS 170: replace problem 15 with 20a,b)
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