Cosmology Christian Stegmann University of Erlangen-Nuremberg - PowerPoint PPT Presentation

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Cosmology Christian Stegmann University of Erlangen-Nuremberg
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Cosmology Christian Stegmann University of Erlangen-Nuremberg

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  1. CosmologyChristian StegmannUniversity of Erlangen-Nuremberg Big Bang today

  2. The Earth … Heute

  3. … one of eight planets today

  4. Stars today

  5. The Milky Way ... today

  6. ... full of stars today

  7. and nebulae today

  8. Our Milky Way today

  9. The Universe is full of galaxies today

  10. Galaxy cluster today

  11. Edwin Hubbles Discovery today • Galaxies travel away from us • the further away, the faster

  12. Galaxies are moving today

  13. Do we understand that? today • We are the centre of the Universe! • The Universe is expanding • Space between galaxies is getting larger Scientifically more attractive!

  14. today

  15. today some time later

  16. How do we measure this? today • Measurement of the velocity • velocity-meter? • Distance • Ruler?

  17. Measurement of the velocity via the red-shift today

  18. Cosmological red shift today Space is expanding

  19. Galaxy-spektroscopy today Star-spektrum Sodium Magnesium Galaxy-spektrum Calcium vGalaxy~ 12000 km/s

  20. Distance measurement today R apparent brightness ~ true brightness . 1/R2

  21. today measured brightness measured brightness known distance measured distance brightness One point and all is determined distance, R

  22. We need lamps! today

  23. Star explosions today • Supernova Typ Ia • Exploding white dwarfs • nuclear bomb of the size of the Earth! • Bright as a whole galaxy • Light up and disappear after a few weeks Supernova 1994D

  24. Where is the supernova? today

  25. Here! today

  26. „Standard candles“ today

  27. The Hubble-Diagram Heute Distance red shift (velocity)‏

  28. today • The Universe is expanding (acclerating)! • The Universe was smaller at earlier times • The Universe was created in a hot phase The Big Bang

  29. World models today

  30. General relativity today • Einstein 1916 • Describes all gravitationally bound systems • planets • black holes • the Universe • Mass produces curvature of the space • Curvature tells masses how to move → gravitation

  31. Space curvature today

  32. Solution Heute Homogeneous but not isotrop Isotrop but not homogeneous • Cosmological principle • We see what every other sees • Isotrop and homogeneous Universe • Friedmann Universe (1922) • World models depend only on • Expansion • Gravitational attraction Isotrop AND homogeneous

  33. Distribution of galaxies today

  34. The accelerated Universe • Einsteins cosmological constant • cosmological constant acts like an anti-gravitation

  35. A travel through the time

  36. First there was … 0

  37. From Big Bang until today 0

  38. A time travel 10-42 s • Age = 10-42 s • The beginning of physics • Age = 10-36 s, T = 1027 K • Strong and electroweak force decouple

  39. The inflation 10-36s • Age = 10-36 s, T = 1021 K • Sudden expansion of the Universe by a factor 1020 – 1030 • The Universe gets flat!

  40. The battle 10-6 s • Age = 10-6 s, T = 1012 Kelvin • Matter and antimatter annihilate • Matter-antimatter-ratio 100000001 : 10000000 • Matter-photon-ratio 1 : 100000000

  41. Nukleosynthesis 1 min • Age = 1 min, T = 109 K • Generation of light elements • Hydrogen, Deuterium, Helium, Lithium

  42. Nuclear fusion 1 min • Fusion in collisions • Fusion requries high temperatures and large densities Strong electo-static repulsion at intermediate distances Forvce particle distance Strong nuclear attraction at smal distances

  43. Primordiale Nukleosynthesis 1 min • Explains the abundances of light elements • 74% Hydrogen • 25% Helium • 1% other • Baryonic density • 3,5∙10-31 g/cm3 or • 0,2 Hydrogen atoms/m3

  44. Generation of atoms 370000 years • Age = 370000 Jahre, T = 3000 Kelvin • First atoms generated • The Universe becomes transparent

  45. Can we see the Big Bang? 370000 years

  46. Back into the past 370000 years 4 light years

  47. 370000 years 2 million light years

  48. Back into the past some billions of light years Each view into the Universe is a view back into the past

  49. The Big Bang fills the sky 370000 Jahre

  50. The Big Bang past - now 370000 years Past: Light 3000 K today: Mikrowaves 3 K