PHYS 252 Introductory Astronomy

This is a one semester introduction to astronomy I started teaching in Bilkent University as of 2016-2017 Fall Semester. In this course we will discuss the celestial spheres, coordinate systems frequently used in astronomy, motions of the celestial bodies, the laws of physics describing these motions, the nature of light, optics and telescopes, the nature and the evolution of stars, our galaxy and other galaxies in the universe, the birth and evolution of the universe, and the search for extraterrestrial life. This course is intended for physical science and engineering majors. A student of this course should understand our place in the cosmos in terms of both our cosmic address and the evolutionary processes that have shaped the universe we live in. It is aimed to explain not only what we know about the universe and the celestial bodies, but also how we know what we know about them.

  • Week 1: Introduction

    • Introducing the course and the material     

    • What is expected from the student and the rules of “the game”

    • What does an astronomer do, how does (s)he work?

    • What astronomers have done and how our perception of the universe has changed

    • Some basic formulae, notation, and nomenclature

  • Week 2 : Celestial Sphere, Coordinate Systems, Motions, and Time

    • Naked eye sky & constellations

    • Coordinate Systems
      • Equatorial coordinate system
      • Observer-oriented coordinate systems (a, HA, z, h)
      • Ecliptic coordinate system
      • Galactic coordinate system
    • Diurnal & Annual Motion of Celestial Objects Across the Skies
      • Diurnal Motion of Celestial Objects
      • Annual Motion, seasons, equinoxes etc.
      • Precession & Nutation
    • Time & Eclipses
      • Solar & Lunar Eclipses, Planetary Transits 
      • Reference Systems
      • Julian Day (heliocentric, barycentric)
      • Sidereal Time
      • Local Time
      • Universal Time

    • Observation 1: Naked eye sky, Observations of Venus, Saturn, and the Moon

  • Week 3: Gravitation, Planetary Motion & The Laws Describing Them
    • A brief History of Universe Models
      • Geocentric Models (From Ancient Greek to Tycho Brahé)
      • Heilocentric Models (From Aristarchus to Copernicus and Galiei)
      • A few words about the modern model
    • Kepler Laws of Motion
    • Newton Laws of Gravity
    • Synodic & Sidereal Periods
    • Tidal forces & Motion

  • Week 4: The Nature of Light
    • Duality Principle & Wave Nature of Light
    • Light as an electromagnetic wave (fundamental definitions)
    • Scattering, reflection, refraction, diffraction
    • Kirchoff laws of radiation
    • Wien’s Law, Stefan – Boltzmann Law
    • Blackbody Radiation (Planck’s Law, Wien & Rayleigh-Jeans Approximations)
    • Spectral Line Formation
    • Doppler Effect

  • Week 5: Optics & Telescopes
    • Refractors vs. Reflectors
    • Light Gathering Power, Magnification, Angular Resolution
    • Blurring Effects of the Atmosphere
    • Light Detectors (From human eye to CCDs)
    • Spectrographs
    • Telescopes Operating at Nonnvisible Wavelengths
    • Space Telescopes
    • Observation 2: Finding an Object with a Telescope

  • Week 6: The Solar System
    • Terrestrial vs. Jovian Planets
    • Satellites of the Planets
    • Chemical Composition of the Planets
    • Asteroids, Trans-Neptunian Objects & Comets
    • Cratering & Impacts
    • Magnetic Fields & The Interiors of Planets

  • Week 7: Star & Planet Formation, Exoplanets
    • Chemical Abundance in Our Galaxy
    • Formation of a Protostar
    • Formation of a Protoplanetary Disk
    • Formation of Planets in the Protoplanetary Disk
    • Formation of the Solar System
    • Exoplanets: Discovery Techniques

  • Week 8: The Nature and Birth of Stars
    • Our Star: The Sun
    • Distances of Stars & How to Measure Them
    • Stellar Motion (Proper Motion)
    • Luminosity, Brightness (Apparent vs. Absolute), Magnitude Scale & Colors
    • Spectra & Spectral Sequence of Stars
    • Hertszprung-Russell Diagram of Stars
    • Stellar Masses, Radii & Chemical Composition
    • Interstellar Gas & Dust
    • Dark Nebulae & Protostars
    • Evolution from a Protostar to the Main Sequence
    • Mass Loss, Circumstellar Disks & Jets
    • Young Stellar (Open) Clusters
    • The Effect of Supernovae in Star Formation
    • Observation 3: Solar Observation

  • Week 9: Stellar Evolution After the Main Sequence
    • Evolution on the Main Sequence
    • End of the Core Hydrogen Burning
    • Helium Burning
    • Red Giant Phase of Evolution
    • Stellar Pulsation & Stellar Variability
    • Binary System Evolution (Differences From Single Star Evolution)
    • Star Populations
    • Post Main Sequence
      • Low Mass Stars
        • Evolution in the Horizontal Branch
        • Asymptotic Giant Branch (Dredge-Up Mechanisms)
        • Ejection of Outer Layers, Planetary Nebulae
        • White Dwarfs
      • High Mass Stars & Compact Objects
        • Supergiants
        • Supernovae
        • Neutron Stars & Black Holes
    • Observation 4: Observing with a Detector

  • Week 10: Our Galaxy & Other Galaxies In the Universe
    • Supermassive Blackholes
    • Location of our Solar System in the Galaxy
    • Observations of Our Own Galaxy
    • Differential Rotation
    • Spiral Arms & Star Forming Regions
    • The Rotation of Our Galaxy & Dark Matter
    • Galactic Nucleus
    • The Disc & The Halo
    • Galactic Formation

  • Week 11-12: Quasars, Active Galaxies, γ-Ray Bursters & Cosmology
    • Quazars, Blazars, Radio Galaxies
    • Active Galaxies & Their Nuclei
    • γ-Ray Bursters
    • Dark Ages of the Unvierse
    • The Big Bang
    • Cosmic Microwave Background Radiation (CMBR)
    • Plasma Stage
    • Dark Matter & Dark Energy
    • Future Evolution of the Universe
    • Towards A Unified Theory of Physics

  • Week 13: The Search for Extraterrestrial Life
    • Exoplanets & Discovery Methods
    • Extraterrestrial Life (in Our Own Solar System) & Astrobiology
    • Drake Equation
    • Search for Extraterrestrial Intelligence (SETI)

  • Textbook: Roger A. Freedman, Robert Geller, William J. Kaufmann III, “Universe: Stars & Galaxies”, W.H. Freeman & Company, New York, 5th ed., 2013; ISBN-10: 1-319-04240-6, ISBN-13: 978-1-319-04240-0
  • The material (presentations, observing runs, exam questions and discussions are uploaded regularly to the Bilkent University’s Moodle System and are only available to the registered students.