The Origin of the Universe

1. The Origin of the Universe Massimiliano Galeazzi MALS 601 Miami, 20 November 2002

2. Summary • The Scientific method • The view of the Universe before 1900: • The Greeks • The Heliocentric system • The view of the Universe after 1900: • Einstein Theory of relativity • Beyond the solar system • Hubble law • The Big Bang theory

3. Philosophy The Scientific Method Observations Theory Predictions Experimental verification

4. Observations Theory Predictions Experimental verification • Sun Observations

5. Observations Theory Predictions Experimental verification Observations • Sun • Moon

6. Observations Theory Predictions Experimental verification Observations • Sun • Moon • Stars

7. Observations Theory Predictions Experimental verification Observations • Sun • Moon • Stars

8. Observations Theory Predictions Experimental verification Philosophy Theory 2 Theory Theory 1

9. Observations Theory Predictions Experimental verification Philosophy Geocentric theory • Movement is not so simple • The movement is not perfectly periodic • There are monthly, annual, and longer term changes

10. Observations Theory Predictions Experimental verification Philosophy Mars Geocentric theory • Movement is no so simple • Planets

11. Observations Theory Predictions Experimental verification Philosophy Geocentric theory • Movement is no so simple • Planets • Distance to the objects

12. Observations Theory Predictions Experimental verification Philosophy Geocentric theory Ptolemy, The Almagest, A.D. c.100-c.178

13. Observations Theory Predictions Experimental verification Philosophy Geocentric theory

14. Observations Theory Predictions Experimental verification Philosophy Geocentric theory SUN Venus EARTH Mercury

15. Observations Theory Predictions Experimental verification Philosophy Simplicity Geocentric theory SUN Venus EARTH Mercury

16. Observations Theory Predictions Experimental verification “Simpler” theories Heliocentric system: the planets (including Earth) rotate around the Sun, and the Earth is also spinning around its axisPythagoreans, Aristarchus of Samos, Plato (?), Copernicus “Hybrid” geocentric system: the Earth is not moving, the planets rotate around the Sun that rotates around the EarthHeraclides of Pontus, Tycho Brahe

17. Observations Theory Predictions Experimental verification Heliocentric theory Nicolaus Copernicus,On the Revolutions of the Heavenly Spheres, 1473-1543 Johannes Kepler, Epitome of Copernican Astronomy, The Harmonies of the World, 1571-1630 Galileo Galilei, Sidereus Nuncius, 1564-1642

18. Observations Theory Predictions Experimental verification Heliocentric theory

19. Observations Theory Predictions Experimental verification The phase of Venus

20. Observations Theory Predictions Experimental verification The phase of Venus Galileo Galilei, c1610

21. Observations Theory Predictions Experimental verification Parallax

22. Observations Theory Predictions Experimental verification Parallax winter

23. Observations Theory Predictions Experimental verification Parallax summer

24. Observations Theory Predictions Experimental verification Parallax summer 1832 Alpha Centauri (nearest star), Henderson Vega, Friedrich von Struve 61 Cygni, Friedrich Bessel

25. 1) High concentration of stars along the milky way  The stars are distributed more in a disk than in as sphere Beyond the solar system

26. Beyond the solar system 2) The star distribution in the milky way is asymmetric, with respect to the Earth, but is rather symmetric with respect to a point in the constellation of Sagittarius (Shapley, 1915)  The Sun is not at the center of the Galaxy

27. Beyond the solar system 3) There are other galaxies in the Universe in addition to ours (Hubble)

28. Beyond the solar system 4) There are billions of galaxies in the Universe  Solar System  Galaxy  Universe  COSMOLOGY

29. Doppler effect

30. Doppler effect

31. Movement Fast toward us Slow toward us Not moving Slow away from us Fast away from us Doppler Effect in Galaxies Earth

32. Observations Theory Predictions Experimental verification  Speed = H · distance (H = Hubble constant) Hubble law (redshift) ALL DISTANT GALAXIES ARE RECEDING FROM US Edwin Hubble 1929

33. Consequences of Hubble Law If all the galaxies move away from us, does it mean that we are at the center of the Universe? What happens if we rewind the tape of the Universe? How old is the Universe?

34. Raisin Cake Balloon Expansion of the Universe If all the galaxies move away from us, does it mean that we are at the center of the Universe?

35. REWIND Expansion of the Universe What happens if we rewind the tape of the Universe?

36. Age of the Universe  speed = H · distance AGE OF THE UNIVERSE IS APRROXIMATELY THE INVERSE OF THE HUBBLE CONSTANT: T ~ 1/H T ~2 1010 years = 20,000,000,000 years

37. Observations Theory Predictions Experimental verification Evolution of the Universe What happened at the beginning? What will happen in the future? • COLD BIG BANG • HOT BIG BANG

38. Observations Theory Predictions Experimental verification The Big Bang Theory

39. Observations Theory Predictions Experimental verification The Big Bang Theory

40. Observations Theory Predictions Experimental verification YES!!! Speed of light: 300,000 Km/s ~ 675,000,000 Miles/h distance = 20,000,000,000 light years ~100,000,000,000,000,000,000,000 Miles The Big Bang Theory Can we try to “see” the explosion?

41. Observations Theory Predictions Experimental verification The cosmic microwave background Arno Penzias and Robert Wilson, 1965 (Nobel Prize in 1978)

42. What will happed in the future?

43. Philosophy What happened before the Big Bang? ?