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Warm up

Warm up. The sun is 4.6 billion years old – how can it continue to produce so much heat and light?. Nuclear reactions. Create new atoms – different elements Fission – splitting or decay Fusion – merging, combines. H fusion.

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Warm up

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  1. Warm up • The sun is 4.6 billion years old – how can it continue to produce so much heat and light?

  2. Nuclear reactions • Create new atoms – different elements • Fission – splitting or decay • Fusion – merging, combines

  3. H fusion • 4 H nuclei collide in a series of steps resulting in 1 He nuclei and ENERGY!!!

  4. Energy transfer • Conduction – energy by direct contact • Convection –heat transfer due to density differences • Radiation – floats away from the source

  5. Energy gets from the sun by radiation • So do radio waves, UV, infrared, etc

  6. Structure of the Sun

  7. Solar flare – a bright temporary outburst of light and energy associated with sunspots • Solar prominence – a large gaseouseruption from the chromosphere

  8. Warm up • If there are so many stars producing light, why is the night sky so dark?

  9. Light • See the source - the flame, the light bulb, the sun • See the reflection • Earth’s atmosphere has lots of stuff to bounce off of • Space doesn’t

  10. Electromagnetic spectrum • Radio waves, microwaves, infrared waves, visible light, X-rays, and gamma rays are all part of the electromagnetic spectrum. • Help us know elements in stars • Provide more information about stellar activity

  11. Composition • Each element has a unique emission spectrum • Matching game

  12. What objects can you see during the day, night or both • Moon • Sun • Stars • Planets • Which of these do you see every night/day, every year, only once

  13. Warm up • What ways do stars differ from each other? • How is the Sun like other stars? • How is the Sun unique?

  14. How did the solar system start • Like any other star, from a nebula etc

  15. Stellar Evolution (The series of changes matter goes through in a star’s formation, life & death.) First random, spread out matter Then a supernova explosion starts things moving/compressing Gravity will keep pulling things together, generating heat & light

  16. Nebula • Places where stars form • Protostars – hot, glowing points of light, gravity is still compressing, rotation • (Planetary systems may start forming) • Forces include gravity (compression), rotation, magnetism, pressure pulling apart • Heat trapped inside • 10 x 106 K Hydrogen FUSION BEGINS

  17. Nebula

  18. Main Sequence • H fusion continues at a steady rate • On the H-R diagram • As H runs out, He fusion begins, leaves main sequence

  19. sun • 4.5 billion years old (life as a main sequence star) • Middle aged • 4.5 billion years left in the current form

  20. Red giant • Core collapsing, He fusion, He consumed, gravity pulling tighter, Carbon, etc • Shell expanding, heat from new nuclear reaction driving shell away, shell goes further, cooling • The elements that form are dependent on the original mass of the star • The rate that fusion occurs is dependent on the original mass of the star • The internal & external temperatures are dependent on the original mass of the star • What happens next is dependent on the original mass of the star

  21. Sun Size • Shell keeps expanding until gravity can’t hold on any longer • Core keeps collapsing, fusion stops, still is hot & glowing • Core has become White Dwarf • Continues to cool and dim

  22. Planetary Nebula • Note the remnant core (white dwarf) surrounded by the expanding shell.

  23. More massive • Red Giant swells to supergiant • If swells & contracts fast enough – supernova explosion • Remnant white dwarf will keep collapsing, if there’s enough mass. • Collapses to a Neutron Star • Keeps collapsing if there’s enough mass • Collapses to a Black Hole

  24. Doppler Effect • Shift away – Red shift • Shift towards – blue shift • Edwin Hubble – discovered most galaxies are moving away from us. • Universe is expanding, it must have been much smaller

  25. Big Bang Theory • A superpowerful explosion of energy and matter 15 billion years ago • Just prior to BB all matter and energy was concentrated into an infinitesimally small ball • After Big Bang, energy and matter began to cool, gravity pulls matter into particles, stars, galaxies begin to form • (H eventually formed)

  26. Planet –solar system – Milky Way – Local Group - Universe

  27. Galaxies • Spiral • Andromeda

  28. Ellipitcal

  29. Irregular

  30. Motion • Rotation of Earth on Axis • Earth orbits Sun • Sun orbits center of Milky Way - • Galaxies are also moving

  31. Test format • Multiple choice • Short answer • Long answer • paragraph

  32. Diagram High vs low mass stars • Neb – proto-MS-RG- PN - WD-BD • Neb- proto-MS-RG-SG-SN-WD-NS –BH • May stop at WD or NS or BH, depending on the mass of the remnant core

  33. Diagram High vs low mass stars • How far and what is the closest star (Sun and other) • Stellar evolution • Compare life span of High and low mass star • What is a star • Difference between a star and a planet – stars produce light/planets reflect light

  34. In a star, what is needed to create a neutron star? • How do scientists use spectrums? • What are absorption/ emission spectrum? • What do we need to start a star forming? • Dust, gas (matter) & energy (shock wave)

  35. Warm up • Why is it so hard to find Black Holes?

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