Outline of the Course TABLE OF CONTENTS Part I—Developing Perspective 1.Our Place in the Universe 2.Discovering the Universe for Yourself 3.The Science of Astronomy Part II—Key Concepts for Astronomy 4.Making Sense of the Universe: Understanding Motion, Energy, and Gravity 5.Light: The Cosmic Messenger Part III—Learning from Other Worlds 6.Our Solar System and its Origin 7.Earth and the Terrestrial Worlds 8.Jovian Planet Systems 9.Remnants of Rock and Ice: Asteroids, Comets, and Pluto Part IV—Stars 10.Our Star 11.Surveying the Stars 12.Star Stuff 13.The Bizarre Stellar Graveyard Part V—Galaxies and Beyond 14.Our Galaxy 15.A Universe of Galaxies 16.Dark Matter, Dark Energy, and the Fate of the Universe 17.The Beginning of Time Part VI—Life on Earth and Beyond 18.Life in the Universe

What You Should Learn From This Class ‘Facts’ about our Universe How we come to accept these facts—the scientific methods The objective of this course is to help you develop a basic knowledge of the universe we live in. However, learning the ‘facts’ should not be the sole purpose of this course. The scientific methods we employed to develop our vision of the universe is also an important subject. It is important to keep in mind that the ‘facts’ that we will be presenting in this course are really our interpretations of the natural phenomena we experienced and observed. Other interpretations may exist for the same phenomena, and that even commonly accepted interpretations today might be revised, or even be proven incorrect in the future. Nevertheless, we have confidence in these ‘facts’ because our interpretations are derived from vigorous and self-consistent reasoning processes, and most of the time, verified by independent experiments and observations. So, in addition to learning the facts that are presented, please also pay attention to the reasoning processes that led us to our interpretations.

The Scientific Methods Define the problem Make Observation Make Hypothesis And Predictions Experiment to test the predictions Theory! YES! Experimental results consistent with predictions? NO

Our Place in the Universe Where are we? Who are we? What is around us? Where did we come from? Where are we going? Hubble Deep Field…most of the features seen in this picture are galaxies. Can you identify the stars?

The ‘spiders’ that holds the secondary mirror of telescopes produces the ‘crosses’ seen around bright stars. Gemini Telescop e on Mauna Kea.

Where Are We? Earth, Solar System, Milky Way Galaxy, The Local Group, The Local Supercluster, The Universe

Who Are We? How did life start? –How did water get here? –How do we build life from lifeless atoms? Are we alone in the universe? –What’s the chance that other life forms exist? –How do we find them if they are out there?

Where are we? Who are we? What is around us? Where did we come from? Where are we going?

What is Around Us in our Universe? Stars Planets Moons (satellites) Asteroids Comets Star systems Star clusters Interstellar medium Galaxies Galaxy clusters Superclusters

What are Stars? Also the objects that are in the process of becoming stars, for example, the protostars. The objects that are the remains of stars that have ‘died’, for example, the neutron stars, or the white dwarfs. A star is ‘dead’ after it had stopped generating energy through nuclear fusion. Nuclear Fusion: The process of combining two lighter elements to make a heavier element, and simultaneously convert some (just a little bit!) of the masses into energy. The total mass of the new element is slightly less than the original total mass. => Four hydrogen atoms can combine to make a Helium atom. Stars are large, glowing ball of gas that generate energy through nuclear fusion in its core.

Planets Maybe made out of rocks, Maybe made out of gas, Maybe both rocky and icy, Much smaller in size than a star, Pretty large compared with other objects in a star system. A planet is an object that orbits a star, and shines primarily by reflecting the light from the star.

Is Pluto a Planet? Pluto (1,160 km) is smaller than our moon (1,738 km) It is not like the rocky inner planets (Mercury, Venus, Earth, and Mas), or the gaseous outer planets (Jupiter, Saturn, Uranus, and Neptune) It is icy, and more like a comet. Hubble Space Telescope image of Pluto and its satellite Charon … Current Event: International Astronomical Union is currently meeting in Prague. One of the issues that’s been debated now (and many times before) is what qualify as a planet…See what you can find on the web about this issue…What is the proposed criteria for planet?

Discovery of Neptune and Pluto The discovery of Neptune and Pluto are good examples of the scientific method… –Both Neptune and Pluto’s existence were predicted based on the small discrepancy between the observed and calculated orbits of known planets. –Their discovery at the predicted positions further enhance the validity of the theory of gravity. Links to the history of Pluto’s discovery The discovery of Pluto Discovering new planets