Astronomy 305/Frontiers in Astronomy

1. Astronomy 305/Frontiers in Astronomy Professor Lynn Cominsky Department of Physics and Astronomy Office: Darwin 329A and NASA E/PO (707) 664-2655 Best way to reach me: lynnc@charmian.sonoma.edu Prof. Lynn Cominsky

2. Astronomy 305/Frontiers in Astronomy • Book:On the Cosmic Horizon by Jeffrey Bennett (Ten Great Mysteries for Third Millenium Astronomy) • Course Organization: • 10 Mysteries + three more that I have added • And an introduction, and a review • Interactive lectures – lots of activities! Prof. Lynn Cominsky

3. Astronomy 305/Frontiers in Astronomy • Grades • 15% - attendance as evidenced by classroom worksheets (1% per week) • 20% - long, research style paper. Topicdue 11/11/03, paper due 12/9/03 • 15% for in-class small group presentation • 15% x 2 for “book reports” on your choice of books from class list, due 9/30/03 and 10/28/03 • 20% for short answer final exam, 12/16/03 Prof. Lynn Cominsky

4. Astronomy 305/ Book List • Black Holes and Time Warps by Kip Thorne  • Black Holes and the Universe by Igor Novikov • Accelerating Universe by Mario Livio • Runaway Universe by Donald Goldsmith  • Einstein’s Unfinished Symphony by Marcia Bartusiak  • The Hole in the Universe by K. C. Cole • The Extravagant Universe by Robert Kirshner Prof. Lynn Cominsky

5. Astronomy 305/Book List (continued) • Flash! The Hunt for the Biggest Explosions in the Universe by Govert Schilling  • How the Universe Got Its Spots by Janna Levin • Wrinkles in Time by George Smoot • Unveiling the Edge of Time by John Gribbin • Before the Beginning by Martin Rees • The Inflationary Universe by Alan Guth • Strange Matters by Tom Siegfried • Cosmic Bullets byRoger Clay and Bruce Dawson Prof. Lynn Cominsky

6. Astronomy 305/Book Report grading • Present a succinct, yet thorough overview of the book that encompasses the key elements of the book’s content. The goal here is to convince me that you have read the entire book. • Connect the book’s main topic to the material presented during one or more of the classroom sessions (or chapters of the Jeff Bennett book). Your goal here is to convince me that you have learned something about at least one of the subjects we are discussing in class. • Book report must be well written, and free of grammatical and spelling errors. Prof. Lynn Cominsky

7. Astronomy 305/Book Report grading • Book report must not contain any plagiarized material – use quotes and refer to page numbers!! •  Book reports are expected to be approximately 5 pages. Your grade will be lowered if your report is either too short or too long. Use 12 point type, double spaced, and standard margins from Word or other program. • Make sure to put your name on the report. No fancy covers please. Prof. Lynn Cominsky

8. Other information of interest: • Class web page: http://glast.sonoma.edu/~lynnc/courses/a305/ • Prof. J. Tenn’s A305 course information http://www.phys-astro.sonoma.edu/people/faculty/tenn/A350/ • Prof. G. Spear’s A305 course information http://www.phys-astro.sonoma.edu/people/faculty/spear/courses/A305.html • My group’s home page: http://epo.sonoma.edu • Imagine the Universe! http://imagine.gsfc.nasa.gov Prof. Lynn Cominsky

9. Astronomy 305/Course Outline Prof. Lynn Cominsky

10. Astronomy 305/Course Outline Prof. Lynn Cominsky

11. Early View of the Universe What do you know about the Universe? Prof. Lynn Cominsky

12. Introductory Activities • Project group selection • Assessment Quiz • Do this as individuals • Cosmic Survey • Do this in small groups • You are given pictures of different astronomical objects • Put them in order of size • Put them in order of distance • Put them in order of age Prof. Lynn Cominsky

13. Powers of Ten • Scientific Notation • 10n means 10 x 10 x 10 x 10 … [n times] • 10-n means 1/(10 x 10 x 10 ….) [n times] • 10n > 1  it is a 1 followed by n zeroes (102 = 100) • 10-n < 1  it is decimal point, (n-1) zeroes, then 1 (10-2 = 0.01) • There are 1010 –1011 stars in our galaxy, and a similar number of galaxies in the Universe Prof. Lynn Cominsky

14. Sizes and Magnitudes • There are 1010 –1011 stars in our galaxy, and a similar number of galaxies in the Universe • Each star weighs ~1030 kg and contains more than 1057 atoms • The radius of a typical star is ~108 m • Each atom weighs ~10-27 kg and has a radius of about 10-10 m • 1 light year is 9.5 x 1015 m Prof. Lynn Cominsky

15. Powers of Ten Video • Produced by Charles and Ray Eames • Describes the journey into Outer Space and then into Inner Space • Each step is a factor of ten in distance Prof. Lynn Cominsky

16. Let There Be Light! • c = 3 x 108 m/s • E = energy • = wavelength • n = frequency • h = Planck’s constant • = 4 x 10-15 eV sec • It’s not just a good idea, it’s the law! E = h c / l n = c / l Prof. Lynn Cominsky

17. Prof. Lynn Cominsky

18. VLA COBEIRASEUVEChandraGLAST HST/Keck Seeing the Light Prof. Lynn Cominsky

19. What emits EM radiation? • Everything does! • Often called thermal or blackbody radiation • the hotter the object, the shorter the wavelength of the peak • the hotter the object, the more intense the radiation Prof. Lynn Cominsky

20. What’s a good blackbody? • Stars • The Universe! Prof. Lynn Cominsky

21. Radio • Cool objects (0 to a few 10s Kelvin) • Synchrotron radiation: electrons spiralling • around magnetic fields • Bremsstrahlung: collisionally • accelerated electrons • Cold molecular clouds • Planets • pulsars • Radio galaxies • Intergalactic matter Prof. Lynn Cominsky

22. Microwave • a bit warmer objects (10s to 100K) • microwave generator • warm molecular clouds • Planets • water masers • Galaxies • The Universe! Prof. Lynn Cominsky

23. Infrared • warm objects (100s to about 2000 K) • Nebulae • Planets • “Normal” stars • Enshrouded protostars • Galaxies Video from SIRTF Prof. Lynn Cominsky

24. Visible • hot objects (2000 to about 10000 Kelvin) • “Hot” speaker for next week! • Nebulae • Planets • “Normal” stars, sun-like • and hotter • Galaxies Prof. Lynn Cominsky

25. Ultraviolet • hotter objects (10,000 to about 100,000 Kelvin) • Nebulae • Planets with magnetic fields • (aurorae) • O-F stars • Pulsars • Galaxies Prof. Lynn Cominsky

26. X-rays • very hot objects (100,000 to a few 106 Kelvin) • Synchrotron radiation • Inverse Compton scattering • Bremsstrahlung • Planets • O star winds • solar corona • White dwarfs • Pulsars • Black holes • Galaxy clusters • Dark matter, indirectly Prof. Lynn Cominsky

27. Gamma Rays • Extremely energetic objects • Radioactive decay (Co56, Ti44) • Fusion • Cosmic ray/gas interaction • matter/antimatter annihilation • magnetic fields • supernovae • Diffuse Galactic emission • Active galaxies • (some) Pulsars • black holes • Gamma Ray Bursts Prof. Lynn Cominsky

28. Gamma Rays • Extremely energetic objects • Radioactive decay (Co56, Ti44) • Fusion • Cosmic ray/gas interaction • matter/antimatter annihilation • magnetic fields • supernovae • Diffuse Galactic emission • Active galaxies • (some) Pulsars • black holes • Gamma Ray Bursts Prof. Lynn Cominsky

29. Other uses for Gamma Rays New Hulk movie uses LBNL’s Gamma-sphere But it really detects gamma-rays, rather than emitting them. Prof. Lynn Cominsky

30. Different Views from the Inside Prof. Lynn Cominsky

31. Invisible Universe GEMS Activity • Different stations have different types of light sources and detectors • All stations have same set of materials • Try each of the 5 stations • For each material: Predict whether or not it will block the light, then test your prediction • Write your predictions and results down on the worksheets that are provided • Hand in worksheets before leaving class Prof. Lynn Cominsky