Phy 3700 Cal State East Bay Fall 2008 Dr. Stephen Asztalos XIA,
LLC Big Bang and other Cosmologies Slide 2 2 Introduction
Instructor: Steve Asztalos Location: Concord Campus CCLB-232
Meeting times: Tues. 6:30-10:00 p.m. Cell Phone: 510-508-6548
Email: [email protected] Slide 3 3 Why cosmology and not something
else? Why should I study cosmology Cosmology has entered an new era
a so- called era of precision cosmology (Mike Turner University of
Chicago) Since the early '90s an explosion of startling
discoveries, such as We are bathed in photons from the Big Bang the
cosmic microwave background The geometry of the universe is flat
You and I make up only a tiny faction of al the matter in the
universe. Instead of stars and stuff, it is filled with Dark
matter, and is accelerating due to Dark energy Slide 4 4 Logisitics
Where do I get course information? Syllabus, course information,
homework and other tidbits
http://kelly.pernell.com/~phy3700http://kelly.pernell.com/~phy3700
Will be updated frequently and will serve as main means of
communication between classes What are the prerequisites?
Undergraduate physics, algebra and geometry I will gently
reacquaint you with concepts you probably knew at one point but
have since forgotten Nothing, however, can replace good ol'
thinking and asking good questions Slide 5 5 A Caveat Phy3700 is a
4-unit course crammed into 10 short weeks. Accordingly, the work
load (defined as work/time) will be high. I strongly encourage
attending all 10 classes, doing your homework and paying attention.
Slide 6 6 Cosmogony vs cosmology Our era is by no means the first
to formulate fundamental questions relating to our origin.
Essentially all cultures are driven to understand Have the heavens
and Earth existed forever? If not, how did it all begin? Will the
Universe come to an end? How did humans come about, and what is
their role in the Universe? Cosmogony = an explanation of the
origin and evolution of the Universe Cosmology =the scientific
study of the formation, structure, and evolution of the Universe
Slide 7 7 Cosmogony Attempts to explain how the Cosmos and humans
(and things important to their existence) came into being. Humans
play a central role in the story The story that is woven is
mythological in nature but each culture's cosmology contains
concepts that are central to their existence, e.g., mountains, snow
wolves, etc. Nonetheless, there is a good deal of similarity among
creation myths reflecting a common human experience of birth and
death. Most myths invoke catastrophes and supernatural occurrences
to give them impact. In any event, they attempt to bring order to
an often frightening and random world. Slide 8 8 Example cosmogony
An Inuit creation myth Slide 9 9 Cosmology Does not place humans at
the center of the quest to understand the universe Incorporates
Leucippus principle of causality: nothing happens at random;
everything happens out of reason and necessity. The universe was
not ruled by gods.
(http://en.wikipedia.org/wiki/Cosmology)Leucippuscausalitygods
Derives from data = objective (reproducible), quantitative
observations of the physical world. Models/theories are continually
re-evaluated based on the scientific method. To be scientific, a
theory must be falsifiable : whole or part may be rejected based on
new data. New data can support an existing theory, but cannot prove
it Prediction (deduction) General Theory The real world Observation
(+induction) Slide 10 10 The earliest cosmology It's not too
surprising that the Greeks the culture that gave rise to many 1 st
s - democracy, the objective historical narrative (on the
Peloponnesian war), etc. - was to introduce rational thought and
apply it to the sciences. The Greeks were champions of the logic
and appreciated deduction (read any of Plato's discourses) Rather
than attribute everything to the God's they assumed that things can
be known through cause and effect They were intoxicated with
mathematics and knew the importance of comparing theory with data,
though their appreciation of the pure forms caused them to elevate
theory above observation Slide 11 11 The Mathematical Earth Through
observation the Greeks had surmised that the Earth was spherical
Observations of the Earths shadow on the Moon during lunar eclipses
As one travels North to South the orientation of constellations
changes Observations of ships sailing over the horizon Slide 12 12
Greek science Eratosthenes and Aristarchus were emblematic of
Greecian intellectual pursuits Erastothenes accurately estimated
the circumference of the Earth Aristarchus estimated the distance
to the Sun
