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Astronomy 101 The Solar System Tuesday, Thursday 2:30-3:45 pm Hasbrouck 20 Tom Burbine tomburbine@astro.umass.edu. Course. Course Website: http://blogs.umass.edu/astron101-tburbine/ Textbook: Pathways to Astronomy (2nd Edition) by Stephen Schneider and Thomas Arny .

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  1. Astronomy 101The Solar SystemTuesday, Thursday2:30-3:45 pmHasbrouck 20Tom Burbinetomburbine@astro.umass.edu

  2. Course • Course Website: • http://blogs.umass.edu/astron101-tburbine/ • Textbook: • Pathways to Astronomy (2nd Edition) by Stephen Schneider and Thomas Arny. • You also will need a calculator.

  3. Office Hours • Mine • Tuesday, Thursday - 1:15-2:15pm • Lederle Graduate Research Tower C 632 • Neil • Tuesday, Thursday - 11 am-noon • Lederle Graduate Research Tower B 619-O

  4. Homework • We will use Spark • https://spark.oit.umass.edu/webct/logonDisplay.dowebct • Homework will be due approximately twice a week

  5. Class Averages • For people who took all 4 tests: • Class average is 81 • Grades range from a 98.5 to a 55.4 • Scores will go up when the lowest exam grade is dropped after the final

  6. A (92.50 – 100) • A- (89.50 – 92.49) • B+ (87.50 – 89.49) • B (82.50 – 87.49) • B- (79.50 – 82.49) • C+ (77.50 – 79.49) • C (72.50 – 77.49) • C- (69.50 – 72.49) • D (59.50 – 69.49) • F (below 59.49)

  7. Final • Cumulative • Monday - 12/14 • 4:00 pm • Hasbrouck 20 • Review Session • Sunday -12/13 • 3:00 pm • Hasbrouck 134

  8. Formulas you may need to know • p2 = a3 • F = GMm/r2 • F = ma • a = GM/r2 • Escape velocity = sqrt(2GM/r) • T (K) = T (oC) + 273.15 • c = f* • E = h*f • KE = 1/2mv2 • E = mc2 • Density = mass/volume • Volume = 4/3r3

  9. More Formulas • Power emitted per unit surface area = σT4 • λmax (nm) = (2,900,000 nm*K)/T • Apparent brightness = Luminosity 4 x (distance)2

  10. Intelligent Life • Intelligent life that we can detect is usually defined as life that can build a radio telescope

  11. Radio • Transmitting information over radio waves is very cheap • uses equipment that is easy to build • has the information-carrying capacity necessary for the task • The information also travels at the speed of light.

  12. Fermi’s Paradox • Where are they?

  13. Fermi’s Paradox • Why have we not observed alien civilizations even though simple arguments would suggest that some of these civilizations ought to have spread throughout the galaxy by now?

  14. Reason for question • Straightforward calculations show that a technological race capable of interstellar travel at (a modest) one tenth the speed of light ought to be able to colonize the entire Galaxy within a period of one to 10 million years.

  15. Explanation • Interested in us but do not want us (yet) to be aware of their presence (sentinel hypothesis or zoo hypothesis)

  16. Explanation • Not interested in us because they are by nature xenophobic or not curious

  17. Explanation • Not interested in us because they are so much further ahead of us

  18. Explanation • Prone to annihilation before they achieve a significant level of interstellar colonization, because:     (a) they self-destruct     (b) are destroyed by external effects, such as:         (i) the collision of an asteroid or comet with their home world         (ii) a galaxy-wide sterilization phenomenon (e.g. a gamma-ray burster       (iii) cultural or technological stagnation

  19. Explanation • Capable of only interplanetary or limited interstellar travel because of fundamental physical, biological, or economic restraints

  20. Fermi’s paradox • The Fermi paradox is the apparent contradiction between high estimates of the probability of the existence of extraterrestrial civilizations and the lack of evidence for, or contact with, such civilizations. • http://en.wikipedia.org/wiki/Fermi_paradox

  21. Jupiter • Largest planet • Mass - 1.899×1027 kg (317.8 Earths) • Jupiter is 2.5 times more massive than all the other planets combined • Mean density - 1.326 g/cm3 • Equatorial diameter - 142,984 km (11.209 Earths)

  22. Probes to Jupiter • Pioneer 10 – 1973 • Pioneer 11 - 1974 • Voyager 1 – 1979 • Voyager 2 - 1979 • Ulysses - 1992 • Galileo – 1995 - Orbiter • Cassini - 2000

  23. Jupiter • Jupiter's atmosphere is composed of ~81% hydrogen and ~18% helium. • Jupiter probably has a core of rocky material amounting to something like 10 to 15 Earth-masses. • Above the core lies the main bulk of the planet in the form of liquid metallic hydrogen. This exotic form of the most common of elements is possible only at pressures exceeding 4 million bars • 1 bar ≈ standard atmospheric pressure at sea level on Earth.

  24. Jupiter is composed • relatively small rocky core • surrounded by metallic hydrogen • surrounded by liquid hydrogen • surrounded by gaseous hydrogen.

  25. Clouds • clouds of ammonia (NH3), methane (CH4), ammonia hydrosulfide (NH4HS)

  26. zone for the light stripes • belt for the dark stripes • http://en.wikipedia.org/wiki/Cloud_pattern_on_Jupiter • The differences in colors are caused by slight differences in chemical composition and temperature • http://zebu.uoregon.edu/~imamura/121/lecture-13/vjupitr2.mov

  27. Galileo Probe

  28. Great Red Spot • A particularly violent storm, about three times Earth's diameter, is known as the Great Red Spot, and has persisted through more than three centuries of human observation. • The spot rotates counterclockwise, once every 7 days.

  29. Jupiter’s Rings • Jupiter has a faint planetary ring system composed of smoke-like dust particles knocked from its moons by meteor impacts.

  30. Jupiter has four rings

  31. Voyager 1 and 2 • Voyager 2 launched first (1977) • Then Voyager 1 (1977)

  32. Grand Tour • Planetary Grand Tour was an ambitious plan to send unmanned probes to the outermost planets of the solar system. Conceived by Gary Flandro of the Jet Propulsion Laboratory, the Grand Tour would have exploited the alignment of Jupiter, Saturn, Uranus, Neptune and Pluto

  33. Voyager 2 • Went to Jupiter, Saturn, Uranus, and Neptune

  34. Voyager 1 • Went to Jupiter and Saturn

  35. Voyager Golden Record

  36. Pioneer 10 and 11 Plaques (1972)

  37. Saturn

  38. Saturn • Known since prehistoric times • Galileo was the first to observe it with a telescope in 1610 • In 1659, Christian Huygens correctly inferred the geometry of the rings • Saturn is the least dense of the planets; its density (0.7 g/cc) is less than that of water.

  39. Rings • Very thin • 250,000 km or more in diameter they are less than one kilometer thick • The ring particles seem to be composed primarily of water ice, but they may also include rocky particles with icy coatings.

  40. Roche Limit • Rings are either a satellite torn apart by tidal forces or material that was never allowed to condense into moons because of the tidal forces

  41. http://csep10.phys.utk.edu/astr161/lect/saturn/rings.html

  42. Cassini-Huygens • Visited Saturn and Titan

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