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Astronomy 101: The Solar System

Join us for an in-depth exploration of our solar system, covering topics such as the planets, asteroids, comets, and more. This course meets on Tuesdays and Thursdays from 2:30-3:45 pm in Hasbrouck 20.

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Astronomy 101: The Solar System

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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. HW #5 • Due today

  6. HW #6 • Due Tuesday

  7. http://www.post-gazette.com/pg/09271/1000779-369.stm

  8. Messenger just flew by Mercury http://www.msnbc.msn.com/id/33092470/ns/technology_and_science-space/

  9. Energy • Energy is the ability to generate motion

  10. Conservation of Energy • Energy is neither created or destroyed – it just changes forms • Conservation of Energy • The energy in a closed system may change form, but the total amount of energy does not change as a result of any process.

  11. Energy units • In English Units, we use calories to measure energy • In science (and in this class), we will use joules to measure energy • 1 Joule = 1 kg*m2/s2

  12. 3 basic categories of energy • Kinetic energy – energy of motion • Potential energy – energy being stored for possible conversion into kinetic energy • Radiative energy – energy carried by light

  13. Kinetic energy • Kinetic energy = ½ mv2 • m is mass in kg • v is velocity in meters/s • Remember: a joule has units of kg*m2/s2

  14. How much kinetic energy does a 2 kg rock have if it is thrown at 20 m/s? • Kinetic energy = ½ mv2 • A) 200 J • B) 400 J • C) 40 J • D) 800 J

  15. Answer • KE = ½ * 2 * (20) *(20) = 400 joules

  16. Thermal energy (kind of kinetic energy) • Temperature is a measure of the average kinetic energy of the particles • Higher temperature – more kinetic energy, particles moving faster • For examples, air molecules around you are moving at ~600 m/s http://eo.ucar.edu/webweather/molecules.html

  17. Temperature scales • In America, we use Fahrenheit • Water freezes at 32 degrees F • Water boils at 212 degrees F • Everywhere else, they use Celsius • Water freezes at 0 degrees C • Water boils at 100 degrees C

  18. In Science • Temperature is measured in Kelvin • Zero Kelvin is absolute zero – nothing moves • Add 273.15 to the Celsius temperature to get the Kelvin temperature • 273.15 Kelvin = 0 degrees Celsius

  19. Gravitational Potential Energy • Gravitational Potential Energy released as an object falls depends on its mass, the strength of gravity, and the distance it falls • For example, your gravitational potential energy increases as you go farther up in the air • This is because you hit the ground at a faster speed if you jump from a higher distance

  20. Gravitational Potential Energy • PE = -G m*M/r • G is the Gravitational constant • m is mass of one body • M is mass of second body • r is distance (people also use variable d)

  21. KE + PE = 0 • As kinetic energy increases, potential energy decreases

  22. Converting Mass to Energy • What is the most famous formula in the world?

  23. E = mc2 • m is mass in kilograms • c is speed of light in meters/s (3 x 108 m/s) • So E is in joules • very small amounts of mass may be converted into a very large amount of energy and

  24. Who came up with it?

  25. How much energy can be produced if you can convert 10 kg of material totally into energy? • E = mc2 • A) 3.0 x 108 J • B) 3.0 x 1016 J • C) 9.0 x 1017 J • D) 9.0 x 1010 J

  26. Answer • E = 10 kg * (3 x 108 m/s) * (3 x 108 m/s) • E = 10* (9 x 1016) J • E = 90 x 1016 J • E = 9.0 x 1017 J

  27. Mass-Energy • E=mc2 • So Mass is a form of potential energy • Where is one place where you see mass converted into energy?

  28. Light • Light is a form of energy

  29. Light • These are all forms of light • Gamma rays • X-rays • Ultraviolet light • Visible light • Infrared light • Radio waves

  30. Light • Can act as a particle • Can also act as a wave

  31. Particle aspect • Particles called photons stream from the Sun and can be blocked by your body

  32. Photons • Light is quantized • Comes in discrete packets called photons

  33. Wave aspect

  34. Thomas Young Experiment • http://micro.magnet.fsu.edu/primer/java/interference/doubleslit/

  35. Characteristics of waves • velocity = wavelength x frequency • Wavelength = distance • Frequency = cycles per second = hertz

  36. For light • c = wavelength x frequency • In vacuum, speed of light stays the same • So if wavelength goes up • Frequency does down • f = frequency • λ = wavelength • c = λ x f

  37. Calculations • c = λ x f • So if the wavelength is 1 x 10-12 m • 3 x 108 m/s = 1 x 10-12 m * f • f = 3 x 108 m/s/1 x 10-12 m • f = 3 x 1020 s-1 = 3 x 1020 Hz

  38. Calculations • c = λ x f • So if the frequency is 1 x 1015 Hz • 3 x 108 m/s = λ * 1 x 1015 Hz • λ = 3 x 108 m/s/1 x 1015 Hz • λ = 3 x 10-7 m

  39. Energy of light • Energy is directly proportional to the frequency • E = h * f • h = Planck’s constant = 6.626 x 10-34 J*s • since f = c/λ • Energy is inversely proportional to the wavelength • E = hc/λ

  40. VIBGYOR violet red Higher the frequency, Higher the energy of the photon Higher the wavelength, Lower the energy of the photon

  41. ROYGBIV • ROYGBIV • Red – long wavelength • Violet – short wavelength

  42. http://www.arpansa.gov.au/images/basics/emr.jpg

  43. Calculations • What is the energy of a radio wave with a frequency of 1 x 107 Hz? • E = h * f • h = Planck’s constant = 6.626 x 10-34 J/s • E = 6.626 x 10-34 J/s * 1 x 107 • E = 6.626 x 10-27 J

  44. Calculations • What is the energy of a gamma ray photon with wavelength of 1 x 10-15 m • E = hc/λ • h = Planck’s constant = 6.626 x 10-34 J/s • E = 6.626 x 10-34 J/s * 3 x 108 m/s / 1 x 10-15 m • E = 1.99 x 10-10 J

  45. So why are some types of radiation dangerous? • Higher the energy, the farther the photons can penetrate • So gamma and X-rays can pass much more easily into your the body • These high-energy photons can ionize atoms in cells • Ionization means removes electrons from an atom

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