Planets, Stars, Galaxies, and the Universe

Course Structure


The learning environment

ASTRO 801 will be conducted entirely on the World Wide Web. There are no set class meeting times, but you will be required to complete weekly assignments. Registered students in this course will need to navigate between several environments in the World Wide Web. These include:

  • This site - The instructional materials in this site include 12 lessons, plus this course introduction and orientation. Each lesson contains interactive exercises, links, animations, movies, and novel explanations of the basic scientific principles related to the objects in the Universe and their environments.
  • Canvas - Canvas is Penn State's secure course management system. In Canvas, registered students consult course calendars, communicate with instructors and fellow students, submit assignments, receive feedback from the instructor, take online quizzes and surveys, and check assignment scores and course grades. 

New to ASTRO 801?

Only students who are registered for this course will have access to the Canvas space for this course. Students who register for this Penn State course gain access to assignments and instructor feedback, and earn academic credit. Information about this course and the online Masters of Education in Earth Sciences is available at the M.Ed. in Earth Sciences website.

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Not registered? Students who register for this Penn State course gain access to assignments and instructor feedback and earn academic credit. Read more about Penn State's Online Geospatial Education programs.

Topics of study

Observations by modern ground-based and space-based observatories have fueled significant changes in our understanding of the Universe. The Solar System contains only 8 planets but has many thousands of Kuiper Belt Objects, including Pluto. Large area sky surveys have taken inventory of the stars in the Milky Way Galaxy and galaxies in the Universe and determined that only 4% of the mass of the universe is found in luminous objects. Besides the mysterious “dark matter,” we now know that the energy budget of the universe is dominated by “dark energy,” which is causing the expansion of the Universe to accelerate. ASTRO 801: Planets, Stars, Galaxies, and the Universe will provide science educators with a strong foundation in astronomy, allowing them to critically evaluate the evidence for the most recent advances in our understanding of the Solar System, our Galaxy, and the Universe.

Photo from the Hubble telescope showing an edge-on galaxy
NASA's Hubble Space Telescope has imaged an unusual edge-on galaxy, revealing remarkable details of its warped dusty disc and showing how colliding galaxies trigger the birth of new stars.
Image courtesy of JPL NASA Jet Propulsion Laboratory. Image source: Earth Science World Image Bank

Astronomers use observations of the light from distant sources to discover the nature of these objects and their environment. ASTRO 801 will lead you to an understanding of light and the instruments for its detection. You will see how careful analysis of these observational data and theoretical models are used to solve the mysteries of the Universe.

ASTRO 801 will combine digital video, audio, simulation models, and the wealth of astronomical imagery from NASA’s Hubble, Chandra, and Spitzer Great Observatories. You will use highly detailed planetarium software and simulated observing experiences to directly explore the night sky to make the same observations that research astronomers perform in their work. You will be granted licenses to use the courseware developed for this course in your own secondary classroom.


Lesson 1: Motions in the Sky and the 3D Geometry of the Sun, Earth, Moon System

  • Introduction
  • Day and Night
  • The Path of the Sun in the Sky
  • The Height of the Sun in the Sky
  • The Phases of the Moon
  • Eclipses

Lesson 2: Orbits and the Laws of Kepler and Newton

  • Introduction
  • Naked Eye Observations of the Solar System
  • The Geocentric Model of the Solar System
  • The Heliocentric Model of the Solar System
  • Kepler’s Three Laws
  • Newtonian Gravitation

Lesson 3: Electromagnetic radiation and Astronomical Observations

  • Introduction
  • The Wave Properties of Light
  • Spectra
  • Radio Waves to Gamma-rays
  • Blackbody Radiation
  • Kirchoff’s Laws and Spectroscopy of Astronomical Objects
  • Telescopes
  • The Effect of the Earth’s Atmosphere on Astronomical Observations

Lesson 4: The Properties of Stars and Stellar Classification

  • Introduction
  • Colors, Temperatures, and Spectral Types of Stars
  • The Distances to Nearby Stars
  • The Luminosity and Apparent Brightness of Stars
  • The Hertzsprung-Russell Diagram
  • Stellar Velocities

Lesson 5: The Early Stages of Stellar Evolution

  • Introduction
  • Nebulae and the Interstellar Medium
  • The Process of Star Formation
  • Nuclear Fusion
  • Stellar Evolutionary Tracks in H-R Diagrams
  • Brown Dwarfs - Failed Stars
  • Binary Stars
  • Variable Stars

Lesson 6: The Late Stages of Stellar Evolution

  • Introduction
  • The Transition to the Red Giant Phase
  • The Final Stages of Life for Sun-Like Stars
  • White Dwarfs, the Chandrasekhar Limit, and Novae
  • The Final Stages of Life for Massive Stars
  • Supernova Nucleosynthesis and Supernova Remnants

Lesson 7: Star Clusters

  • Introduction
  • Examples of Star Clusters
  • Open Clusters vs. Globular Clusters
  • Estimating the Age of a Star Cluster 3
  • The Distances of Star Clusters
  • Using Star Clusters as Tracers of the Milky Way

Lesson 8: The Milky Way Galaxy

  • Introduction
  • The Appearance of the Milky Way in the Night Sky
  • The True 3D Shape of the Milky Way
  • The Multiwavelength Milky Way
  • Sgr A* – The Black Hole at the Core of the Galaxy
  • The Local Group

Lesson 9: Galaxies in the Universe

  • Introduction
  • The Spiral Nebulae and the Great Debate
  • Hubble’s Tuning Fork and Galaxy Classification
  • Galaxy Formation and Evolution
  • Exotic galaxies
  • The Large Scale Structure of the Universe

Lesson 10: Cosmology

  • Introduction
  • Olber’s Paradox
  • Hubble’s Law
  • The Expanding Universe
  • The Age of the Universe
  • Dark Matter and Dark Energy

Lesson 11: The Solar System

  • Introduction
  • The Terrestrial Planets
  • The Jovian Planets
  • Asteroids, Comets, and Meteors
  • The Kuiper Belt
  • Why Pluto was Demoted
  • Solar System Formation

Lesson 12: Life in the Universe

  • Introduction
  • The Search for Planets around other Stars
  • The Prospects for Life in the Solar System
  • The Prospects for Life in the Milky Way
  • The Search for Extraterrestrial Intelligence

Course assignments

ASTRO 801 will rely upon a variety of methods to assess and evaluate student learning, including

  • automated online quizzes to keep track of student performance in individual lessons and to help instructors to ensure that students complete required assignments on schedule. Quizzes will include multiple-choice, matching, and short answer questions. For example, students might be presented with an HR Diagram plotting the colors and magnitudes for a population of stars. They would then be asked to identify the region of the diagram that includes all of the helium burning stars by clicking on the plot. Whether they answer correctly or incorrectly, students will immediately receive textual and sometimes graphic feedback.
  • required participation in online discussion groups to provide opportunities for instructors to gauge students’ progress. Instructors will pose weekly problems and ask students to debate likely solutions. Subsequent small group discussions will reveal students' abilities to effectively articulate key concepts.
  • laboratory exercises using software simulations: students will investigate several different concepts by taking data, analyzing the data, and reporting their results.
  • a capstone project that will be used to evaluate students’ knowledge and skills through the production of a learning module that they, in turn, will be able to use to teach course concepts to their own secondary school students.