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Lecture

Astronomy 1021 Lecture Notes - Copernican Revolution, Pseudoscience, Scientific Method


Department
Astronomy
Course Code
ASTR 1021
Professor
Jan Cami

Page:
of 3
ASTRONOMY 1021 October 19th, 2010
Astronomy Lecture 6
What is Science? Kepler’s Laws, Motion, Energy and Gravity…
Setup & Instructions for Starry Night are provided.
Horoscope = 1%
Motions in the Sky = 2%
(pretty much ignored slides for a long while. Download them all)
Revolution in Science…
o Copernican revolution completely changed our ideas
Discussion…
o What is a science mind?
o What do you find difficult about science?
o What is crucial in the Copernican revolution?
o Do you find it important to be able to distinguish science from pseudo-science?
o Why should you care about science?
What is science?...
o Somehow related to scientia (knowledge), includes understanding
o Includes scientific method basic level of scientific thinking
Scientific method…
o Something we know from everyday experience
o Idealized conceptual methodologymany scientific discoveries happen by accident
o Important: feedback mechanism that updates hypothesis when tests fail
(Missed more slides…la la la)
How to recognize pseudo-science…
o Supernatural involved
o Claims that can’t be tested
o Excuses for failed tests
o Anything that makes no sense whatsoever
o Conspiracy required?
ASTRONOMY 1021 October 19th, 2010
Astrology…
o Claim #1 apparent positions of the Sun, Moon and planets among the stars influence
events on earth
o Claim #2 only astrologers have the required powers to “See” and “Feel” this influence
o Claimed #3 Astrological predictions have been tested
o If this is true, very powerful and should be used to our advantage
o We can have a look at the claims to see whether they exhibit the hallmarks of science.
Do they make sense?
o Claim #1 IF planets have influence, it must be through a mechanism we don’t
know yet. It’s related to “astrologically” defined artificial constellations, not the
ones that we see in the night sky. Influence should not depend on distance, and
influence does not exist for Uranus or Neptune, asteroids…and should not be
influenced by the precession of the equinoxes.
o Claim #2 if only they have the power, how can it affect other people? Does not
make much sense… Astrological predictions are rather some vague guidance on
how to live lifenot well testable, never say buy a lottery ticket at 3:27 pm in
the shop on Richmond and you’ll win 327,192$.
o Claim #3 and I missed it…
From tests to theory…
o When test fails update hypothesis
o Successful test: come up with more, different tests.
o Ultimately: hypothesis has been tested in so many different, specific ways (all testable)
that hypothesis is supported by large body of evidence
Scientific theories…
o Quite diff from general meaning of the word “theory” which indicates speculation or
hypothesis
o Can only be replaced by other theories if new theories offer better predictions or have a
large applicability
o Theory means: simple physical principles that can predict and explain many observations
and experiments, and that are supported by large, compelling body of examples.
Motion, Energy & Gravity…
Motivation…
o We can describe many phenomena in the Universefrom small to very large scalesby
using only a few simple laws:
ASTRONOMY 1021 October 19th, 2010
o Newton’s laws of motion
o Conservation laws
o Universal law of gravity
Motion…
o Speed: distance traveled in a certain amount of time
o Velocity: speed and direction
o Acceleration: change of velocity
o Can be change of speed and/or change of direction
o Can be deceleration
o Can be up/down
Acceleration…
o Something you can feel, whereas you don’t feel speed when traveling at constant
velocity (think train or plane)
o Can be measured: a car accelerates from o to 100 km/h in 4 seconds
o Change in velocity over time
o For aficionados: units = (km/h)/s or (m/s)/s = m/s^2
(missed a bunch of slides AGAIIIIN)