1. IAS April 9, 2008 Lawrence Rudnick, University of Minnesota in collaboration with Shea Brown & Liliya Williams A Universe Full of NOTHING

2. EVERYWHERE, EMPTINESS air, atoms, stars, universe WHAT WE DONT SEE THE CURIOUS VACUUM FINDING the BIGGEST NOTHING

3. EVERYWHERE EMPTINESS

4. AIR

5. INTO THE ATOM

6. Lord Ernest Rutherford 1911 Gold Foil Experiment

7. PLANETS & STARS

8. The 3-D Universe: TIME & SPACE 0.0001 sec 100s years 5 min 1000s years

9. Looking back – time and space

10. Structures in the Universe

11. Words of Wisdom The Universe is almost empty, from sub-atomic to cosmic scales

12. WHAT WE DONT SEE

13. DARK Matter Behind the scenes…

14. DARK Energy Behind the scenes…

15. Behind the scenes...

16. Words of Wisdom The Universe is almost empty, from sub-atomic to cosmic scales The most important stuff is what we DONT see (dark matter & energy)

17. THE CURIOUS VACUUM That gravity should be innate, inherent and essential to matter, so that one body may act upon another at a distance through a vacuum, without the mediation of anything else, by and through which their action and force may be conveyed from one to another, is to me so great an absurdity, that I believe no competent faculty of thinking, can ever fall into it. Gravity must be caused by an agent acting constantly according to certain laws; but whether this agent be material or immaterial, I have left to the consideration of my readers. I. Newton, 25 Feb, 1693

18. Making a vacuum The luminiferous aether what medium carries light? Whats left in the vacuum? THE CURIOUS VACUUM

19. Evangelista Torricelli 1640s

20. Von Guericke – the Magdeburg spheres (1654)

21. WHAT CARRIED THE LIGHT?

22. Michelson-Morley 1881, 7

23. Is the vacuum empty? The vacuum is that which is left in a vessel after we have removed everything from it that we can remove from it. James Clerk Maxwell 1892

24. Vacuum Waves Casimir effect: 1948

25. Vacuum Waves Casimir effect

26. Radioactive Decay 210 Po 206 Pb + 4 He

27. E* t > h/ 2 Radioactive Decay energy from the vacuum

28. Have we reached the ultimate vacuum?

29. Words of Wisdom The Universe is almost empty, from sub-atomic to cosmic scales The most important stuff is what we DONT see (dark matter & energy) Even the vacuum is teeming with forces (dark energy) that dominate the dynamics of the Universe

30. FINDING THE BIGGEST NOTHING

31. Early Universe – first look

32. +0.0001 -0.0001 Early Universe +1 +0.1 -0.1 +0.01 -0.01 +0.001 -0.001 2.73K

33. Early Universe – a fine look Wilkinson Microwave Anisotropy Probe

34. Isolating the CMB Cold Spot Early Universe

36. Hole in the NVSS

37. Early Universe Local Universe

38. Late Integrated Sachs-Wolfe (ISW) Effect Energy A CMB photon will change energy as it traverses a potential well -- if the well evolves during the transit. Peebles & Ratra 2003

40. Void Statistics Very unlikely given the current void statistics, such large scales have not been investigated either in observations or simulations Hoyle & Vogeley 2004 Average: δ = -0.94±0.02; R=(15.61±2.84) h -1 Mpc

45. I love talking about nothing. Its the only thing I know anything about. (OW)

47. Olbers paradox

48. LOCAL UNIVERSE

49. How Large of a Void is Needed? We can do an order of magnitude calculation to find the size of the void need to create the cold spot If we assume δ = -1 and z = 0.5-1.0, we calculate that a ~280 Mpc void is need. Void statistics done so far find that the probability of finding a 280 Mpc void is ~5x10 -10 Second order effects could change the size of the void(s) needed Inoue & Silk 2006, 2007

50. What weve learned... CMB has tiny fluctuations from Early Universe, (at 46 billion light years away) plus mysterious cold spot There is a deficit of radio galaxies in the same direction as the cold spot (6-10 billion light years away) If the radio galaxy deficit is due to an empty void, 1 billion light years across, it could be responsible for the WMAP cold spot.