Astronomy 103 Main Ideas to be covered: Lecturer: Prof. Alex Lazarian Office Location: 6289 Chamberlin Hall Email: lazarian@astro.wisc.edu Website: http://www.astro.wisc.edu/~lazarian/ast103_2014/ Office Hours: Mon. 11am-1pm, Wed. 11am-1pm. Meetings at a different time can also be arranged. Course Reading: Pathways to Astronomy Schneider & Arny 4nd edition Exams: 0th training exam -- 0% (Oct. 6) 1st exam – 25% (Oct. 15) 2nd exam—25% (Nov. 10) final exam—30% (Dec. 15) total for homework, quizzes, presentations -- 20% Main Ideas to be covered: *Subject of astronomy (Units 1--4) *Observations of planets and stars (Units 5--12) *Laws of gravity, dark matter (Units 14-20) *Light, atoms, spectra (Units 21--30) *Stars: Sun as an example (Units 49--50) *Learning about stars (Units 52--55) *Birth and evolution of stars (Units 56—63, 69) *When the fuel begins to run out (Units 64--66) *Supernova, neutron stars and black holes (Units 67--68) *Galaxies and quasars (Units 74--77) *Our galaxy- Milky Way (Units 70--73) *The expanding Universe (Units 78--82) *Life in the Universe (Units 83--84) *Review of the course

My PhD is from Cambridge University Prof. V. Ginzburg Martin Rees V. Ginzburg My PhD is from Cambridge University

Why do I study Astronomy? “Education is kindling of a flame, not the filling of a vessel” Socrates

My goals for the course: Share my excitement with Astrophysics Provide a survey of most of Astronomy Show that Astronomy is a quest for our origins Show how science is done Look at my personal web page to know more about my research http://www.astro.wisc.edu/~lazarian/

The Earth The Earth is a planet, a body in orbit around a star (The Sun) Radius: 6371 km (3909 miles) Mass: around 6 billion trillion tons Actual value: 5,970,000,000,000,000,000,000,000 kg Too many zeros! Use 5.97  1027 kg, instead! Metric System Easier to use (everything is a factor of 10!)

The Moon is a satellite, a body orbiting a planet Rocky world, littered with craters Bombarded by meteors Where are the Earth’s craters? Smaller than the Earth Less than 1/80 the mass ¼ the diameter of Earth Small, so cooled quickly! Cold, airless and lifeless

Wide variety of planets in the Solar System The Planets Why are they so different? How did they get this way? Wide variety of planets in the Solar System Rocky, hot and airless worlds Gas giants and ringed wonders Cold planets of blue methane Tiny icy bodies

The Sun The Sun is a star, a huge ball of gas held together by gravity and generating light through thermonuclear reactions Source of all energy in the Solar System 100x wider than the Earth, and 300,000x as massive! Young, yet old 4 billion years old Will last another 5 or 6 billion years

The Solar System Planets, asteroids, comets and dust all held together by the Sun’s gravity Everything goes around the Sun on elliptical paths called orbits All orbits lie in the same plane, like peas rolling around on a dinner plate Too big to describe using meters – we need something more convenient

A convenient measure – the Astronomical Unit It is convenient to measure planetary distances using the Astronomical Unit, or AU 1 AU = average distance between the Earth and the Sun 1 AU ~ 150 million km Some planetary distances: Mercury: 0.4 AU Mars: 1.5 AU Saturn: 10 AU Pluto: 40 AU