The Milky Way, Schroedinger’s Cat, and You

1. The Milky Way, Schroedinger’s Cat,and You Galaxies, the Building Blocks of the Universe Raja Guha Thakurta (in collaboration with Sandra Faber) UCO/Lick Observatory University of California at Santa Cruz Thursday, September 23, 2004 Astronomy 2 (ASTR –002-02) Kresge Town Hall Overview of the Universe

2. You are here! Your Cosmic History(an astronomer’s perspective) You! Protein molecules: Basic building blocks of life Earth and Sun: Home of the C,N,O atoms from which these protein molecules were assimilated Sun’s ancestral stars: Their nuclear fusion reactions produced these C,N,O atoms Galaxy: Large family of stars

3. Relatives of the Milky Way Milky Way

4. Where did the Milky Way Come From? The Answer Will Take Us Back to the Earliest Moments of the Universe

5. The Cosmic Web of Galaxies

6. Formation of Cosmic Structures Under the Influence of Gravity + - A Computer Simulation

7. Points to Ponder • Our bio-chemical history links us to galaxies • The Milky Way and other galaxies • Galaxies like to live near one another • The formation of galaxies: The growth of primordial density fluctuations under the influence of gravity

8. But Where Did the “Seeds” of Cosmic Structure Come From?

9. Quantum Noise 0.5 1.0 0.9995 1.0000 Energy density of the Universe 0 0.99995 1.00000 0.995 1.000 Position in Space Number of radiactive decays per minute 020 40 Number of kernels popping per minute 020 40 0 10 20 30 Time

10. …or… R.I.P. ??? Schroedinger’s Cat(a “thought experiment” by Erwin Schroedinger)

11. A rapid and dramatic phase of expansion shortly after the Big Bang blows up these quantum fluctuations and “freezes” them into the fabric of the Universe. These are the seeds of cosmic structure. Inflation

12. Points to Ponder • The Universe is Nature’s ultimate example of Schroedinger’s cat • Inflation is a very, very brief period of extremely rapid expansion in the infancy of the Universe • We have quantum mechanics and gravity to thank for the existence of galaxies like our Milky Way and indeed for our own existence

13. Prediction #1Galaxy collisions should be common and easily visible

14. Computer Simulation of Colliding Galaxies

15. And This Is What We See…..

16. Prediction #2“Infant” galaxies should look different from mature galaxies

17. Zooming into Deep Space, Looking Back in Time

18. Zooming into Deep Space, Looking Back in Time

19. Distant Galaxies Are Small and Ragged Infant galaxy Young galaxy Mature galaxy

20. Deepest Image of Distant Galaxies

21. The Hubble Space Telescope is in orbit above the Earth’s atmosphere and so is able to take sharp pictures……but….. ….. it is prohibitively expensive to build telescopes that are based in space A new method called “Adaptive Optics” allows us to sharpen the vision of telescopes that are on the ground, by correcting for the blurring caused by the Earth’s atmosphere

22. Prediction #3The farthest things we see should be the early seeds of galaxies

23. Early Seeds: Fluctuations in the Microwave Background Radiation Maps

24. Points to Ponder • Galaxy cannibalism is a common phenomenon in which small serve as buildingblocks from which larger galaxies are assembled • Telescopes are time-machines that enable us to peer into the Universe’s distant past • The after-glow from the Big Bang and early hot phase of the Universe is visible today and indeed even the wrinkles on the face of the early Universe are visible

25. Infant galaxy Spiral galaxy like our own Sun’s stellar ancestors You! Our planet & star Protein molecule Completing the Cycle……