Welcome Astronomy 201 Cosmology

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Welcome! Astronomy 201 --- Cosmology

• Lecture 1 Introduction
• Aug 21, 2007

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At your service

• Instructor
• Prof. Xiaohui Fan
• Office Steward 310
• Office hour Thursday 2-330pm, or by
  appointment
• Emailfan_at_as.arizona.edu, Tel [phone]
• Teaching Assistant
• Mr. Jared Gabor
• Office Steward N305
• Office hour Monday 3-4pm, or by
  appointment
• Emailjgabor_at_as.arizona.edu, Tel [phone]
• Websitehttp//sancerre.as.arizona.edu/fan/ast201
  

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Lectures

• Lecture format
• 75 min lecture
• Activity somewhere in the middle of each lecture
• Quiz
• Video
• Cosmology News of the Week
• Stories
• Your request here
• Powerpoint file will be available online
• Attendance
• You will NOT be graded for attendance
• But be smart, come to the lecture (and maybe it
  is fun!)

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Grading Policy

• Homework 20 (six times during semester)
• Pop Quiz 20 (six times during semester)
• Online Project Report 20
• Using real astronomical data to discovery one of
  three important aspects of modern extragalactic
  astronomy and cosmology
• Galaxy classification
• Expansion of the universe
• Quasars
• Details will be announced in early Oct.
• Reports due Dec 1
• Midterm 20 (close book, in class, Oct 16)
• Final 20 (close book, Dec 13)

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Other Policies

• Make-up Exams
• Only in rare circumstances, and it will be oral
  exam (30 min Q/A session in front of a
  black/white broad)
• Academic Honesty
• We take it seriously!
• Collaboration on online project allowed, but you
  have to write your own report
• Friendly discussion on homework a good idea,
  collaborations on homework answers strongly
  discouraged
• Code of Academic Integrity strictly enforced for
  midterm and final exams

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Textbook

• Stars, Galaxies and Cosmology, by Bennett,
  Donahue, Schneider and Voit
• Online study material at masteringastronomy.com
• http//www.masteringastronomy.com
• Voyager Skygazer software
• Other References
• One Universe At Home in the Cosmos
• New Perspectives in Astrophysical Cosmology
• A Brief History of Time
• Foundation of Modern Cosmology
• Lonely Heart of the Cosmos The Story of the
  Scientific Quest for the Secret of the Universe

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What is Cosmology

• According to Webster Dictionary
• 1. A branch of metaphysics that deals with the
  nature of the universe
• 2. A theory or doctrine describing the natural
  order of the universe
• 3. A branch of astronomy that deals with the
  origin, structure and space-time relationships of
  the universe
• So cosmology is.
• Theology
• Philosophy
• And most recently, a science.
• In this class, we are treating cosmology as an
  empirical science

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What I expect you to take away from this course?

• Learn Cosmology as a science
• What are the basic components of the universe
• What are the basic physical laws that govern the
  universe
• What is the size and age of the universe
• Whats the current theory on origin and evolution
  of the universe (big bang!), and what are the
  evidences that support that theory
• What is the nature of space/time/matter/energy
• What about the dark side of the universe black
  holes, cosmic dark ages, dark matter, dark energy
  etc.
• Learn Cosmology in the context of human society
• What is the scientific method (or, is there a
  scientific method)
• How does human society, in particular religion
  and philosophy affect the advancement of
  cosmology
• How does modern technology affect cosmology
• How does the personality of individual
  scientists, and the culture of the scientist
  community affect cosmology

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But, Most Importantly

• Be curious, ask questions!
• Be open-minded, explore new ideas!
• Be critical, make your own judgment based on
  scientific evidences!
• And have fun!

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Topic Covered

• Part 1 Introduction, Basic concepts (Ch 1 7)
• Part 2 Matter, Energy, Spacetime and Black Hole
  (Ch S1, S2, S3, 18)
• Concepts of relativity
• Gravity and space time
• Building blocks of the universe
• Black holes
• Part 3 Galaxies (Ch 19, 20)
• Milky Way
• Types of Galaxies
• Expansion of the Universe

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Topics Covered

• Part 4 The Evolution of the Universe (Ch 21, 22)
• Galaxy Evolution
• Quasars
• Structures in the Universe
• Dark matter
• Fate of the Universe, dark energy
• Part 5 Early Universe (Ch 23, 24)
• Cosmological Principles
• Cosmic History
• Hot Big Bang
• Inflation
• Theory of Everything???

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From Big Bang to the Galaxy movie
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Chapter 1Our Place in the Universe
Hubble Ultra Deep Field
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1. A Modern View of the Universe
Our goals for learning

• What is our physical place in the Universe?
• Describe our cosmic origins and why we say that
  we are star stuff.
• Why does looking into space mean looking back
  in time?
• What is the scale of the Universe?

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Address Earth

• How would the Universal post office find us?

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What is our place in the universe?
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Star

• A large, glowing ball of gas that generates heat
  and light through nuclear fusion

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Solar (Star) System

• A star and all the material which orbits it,
  including its planets and moons

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Galaxy

• A great island of stars in space, all held
  together by gravity and orbiting a common center

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Universe

• The sum total of all matter and energy that is,
  everything within and between all galaxies

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Where do we come from?

• The first (and simplest) atoms were created
  during the Big Bang.
• More complex atoms were created in stars.
• When the star dies, they are expelled into
  space. to form new stars and planets!

Most of the atoms in our bodies were created in
the core of a star!
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How can we know what the universe was like in the
past?

• Light travels at a finite speed (300,000 km/s).
• Thus, we see objects as they were in the past
• The farther away we look in distance, the
  further back we look in time.

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Example

• We see the Orion Nebula as it looked 1,500 years
  ago.

M31, The Great Galaxy in Andromeda
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Light-year

• The distance light can travel in one year.
• About 10 trillion km (6 trillion miles).

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At great distances, we see objects as they
were when the universe was much younger.

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Sun, 8 light minutes
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Mars, 12 light minutes
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Jupiter, 40 lt min.
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Pluto and Charon, 300 lt min
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A star with planets forming 50 lt year
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Andromeda, a Galaxy like ours, 2 million lt yrs
100 billion Stars 100,000 lt yrs across
You are here!
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Virgo cluster, 60 million lt yrs 1000 galaxies, 6
million lt yrs across
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Coma Cluster, 360 million lt yrs, 1000
galaxies 6 million lt yrs across
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Hubble Deep Field, 10 billion lt yrs
A cluster 4 billion lt yrs 1000 galaxies, 6
million lt yrs across
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Cosmic Background, 13.7 billion lt yrs ? Baby
picture of the universe, 300,000 years after the
big bang
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Can we see the entire universe?
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How do our lifetimes compare to the age of the
Universe?

• The Cosmic Calendar a scale on which we compress
  the history of the universe into 1 year.

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How do our lifetimes compare to the age of the
Universe?

• The Cosmic Calendar a scale on which we compress
  the history of the universe into 1 year.