1. Observational Cosmology Jonathan P. Gardner NASA’s Goddard Space Flight Center

2. Wilkinson Microwave Anisotropy Probe Gary Hinshaw, WMAP Co-I University of Edinburgh, September 3, 2004

3. Hubble Space Telescope

4. James Webb Space Telescope

5. Astronomical Search For Origins Big Bang First Galaxies Galaxies Evolve Stars Planets Life

6. Beginnings are Important … (Origins)... So Are Changes (Evolution) David Jonathan Gardner, June 16, 1998 David Jonathan Gardner, June 16, 2005

7. The First 13.7 Billion Years Big Bang Particle Physics Now Atoms & Radiation: CMB First Galaxies Galaxies Evolve Planets, Life & Intelligence 380,000 years 3 minutes 1 billion years 13.7 billion years 400 million years Dark Matter/ Dark Energy 7 billion years

8. Edwin P. Hubble (the man, not the telescope) Edwin P. Hubble, 1889-1953 1.Classification of Galaxies 2.The “Spiral Nebulae” are “Island Universes” 3.The Universe is Expanding Which is further away? How can you tell?

9. The Hubble Sequence Hubble classified nearby (present-day) galaxies into Spirals and Ellipticals. The Hubble Space Telescope extends this to the distant past.

10. Measuring Distances Cepheid Variable Stars: known period-luminosity relation. Suitable for nearby galaxies Supernovae: known maximum luminosity. Suitable for distant galaxies. Astronomers can measure distances if they know the intrinsic luminosity.

11. Hubble Discovers the Universe Cepheids in the Andromeda galaxy showed it is 8 times further than the most distant star in our Galaxy.  Island Universes! “Planetary Nebula” are within our Galaxy. Hubble at Mount Wilson telescope

12. Doppler Shift

13. Hubble’s Law Velocity in Kilometers per Second

14. Distance + Light travel time = Seeing the past. Looking Backwards in Time Distance Time Here & Now 1 Million light years away, 1 Million years ago 1 Billion light years away 1 Billion years ago Far, Far Away means Long, Long Ago

15. The First Nano-Second

16. How much of the Universe can we see?

17. T 1 T 1 T 2 T 2 Why is the cosmic microwave background temperature so uniform on scales >2°? T 1 = T 2 + O (10 -5 )  >> 2 ° D >> c/H o MAP990008 The Horizon Problem

18. MAP990007 The Flatness Problem 0 5 10 t [Gyr] Density 1ns after BB Why is the universe anywhere close to  =1 now?  =1 is an unstable stationary point. 0 0 Scale Factor a(t) 447,225,917,218,507,401,284,015 gm/cc 447,225,917,218,507,401,284,016 gm/cc 447,225,917,218,507,401,284,017 gm/cc

19. Curved Space-Time 3D Figures by Stuart Levy of the University of Illinois, Urbana-Champaign and by Tamara Munzer of Stanford University for Scientific American. 2D Figures by Ned Wright, UCLA Flat, or Euclidean Space Positive Spherical Space Negative Hyperbolic Space

20. Inflation and a Flat Universe

21. Smooth 3K Cosmic microwave background radiation Clumpy distribution of galaxies - MAP990012 The Structure Problem how did this happen?

22. Inflation solves the problems Before Inflation causally connected quantum fluctuations. After Inflation, previously connected regions are outside the horizon. Later, the regions re- enter the horizon. Quantum fluctuations become galaxies Predictions: Universe is flat. Fluctuations are correlated on different scales.

23. The First Three Minutes

24. Synthesis of Light Elements Light elements, D, He, Li produced ~3 minutes “after Big Bang”. One free parameter in predicted abundances: baryon/photon ratio (note: baryons = atoms) Baryon/photon ratio now measured by CMB (discussed later). Predicted abundances may now be confronted with observed abundances (grey boxes). Some tensions.

25. The First 380,000 Years Wayne Hu and Martin White, Scientific American, February 2004

26. Why Bright Clumps? Remnants of Primordial Oscillations Gravity tries to make matter fall into potential wells Radiation pressure pushed back... Oscillations results… Imprint of event imparted on photons...

27. Sound Waves in the Plasma

28. Baby Picture of the Universe

29. WMAP shows the Universe is Flat Flatness Baryons Dark Matter

30. The First 400 Million Years Barkana & Loeb 2001, Physics Reports, 349, 125 Cooling with atoms Cooling with H 2 3σ3σ 2σ2σ 1σ1σ

31. The First Galaxies What did the first galaxies to form look like? –They are very distant, and very faint.

32. Infrared Light Light from the first galaxies is redshifted from the visible into the infrared. Infrared is heat radiation Most of the Sun’s energy is visible light

33. Deepest View(s) of the Universe 1995 Hubble Deep Field –10 days exposure, small area 1998 Hubble Deep Field South –Repeat in another field 2003 Great Observatories Origins Deep Survey –30x area –infrared with Spitzer, X-ray with Chandra 2004 Hubble Ultra-Deep Field –30 days exposure, more sensitive camera 1996-2006-… Follow-up observations Hubble Ultra Deep Field

35. Finding distant galaxies UV radiation shortward of Lyman limit at 912Å is absorbed by inter- galactic medium. This break is redshifted through successive filters Infrared Visible light technology (CCDs) ends at ~1 micron, so finding galaxies at z>6 requires infrared.

36. History of star-formation in the Universe Star-formation density Bouwens et al. 2005, astro-ph/0509641

37. Prospects for future study at high-z Hubble (2.4m diameter warm telescope): –Reaches to z~6, with claims to 7 or 8. –New camera to be installed in next servicing mission may reach to magnitudes of 28.5 (15 nJy) in the NIR. –No longer has sensitive spectroscopic capability in opt-NIR. Spitzer (0.85m diameter cold telescope): –Reaches to z~6 (same galaxies as HST). –Reaches magnitudes of 26.6 in near- to mid- IR. Ground-based observations (10m warm) –Limited by atmosphere

38. How to win at Astronomy 10 8 16001700180019002000 Galileo Sensitivity Improvement over the Eye Year of observations Telescopes alone Photographic & electronic detection 10 6 10 4 10 2 Huygens eyepiece Slow f ratios Short’s 21.5” Herschell’s 48” Rosse’s 72” Photography Mount Wilson 100”Mount Palomar 200”Soviet 6-m Adapted from Cosmic Discovery, M. Harwit 10 CCDs HST JWST Big Telescopes with Sensitive Detectors in Space 1610 1665 1796 1926

39. HST vs. JWST - temperature Room Temperature -225° Celsius, -370° Fahrenheit

40. HST vs. JWST - orbit 375 miles up Second Lagrange Point, 1,000,000 miles away How will JWST get there? Ariane 5

41. HST vs. JWST - size 2.4 meter diameter 6.5 meter diameter How do you put a 6.5 meter mirror in a 5 meter rocket?

42. The First 1 Billion Years

43. When was re-ionization? Fan et al. 2001, AJ, 122, 2833 Patchy Absorption Redshift Wavelength Lyman Forest Absorption Black Gunn- Peterson trough z<z i z~z i z>z i Neutral IGM. Kogut et al. 2003, ApJS, 148, 161 Fan et al. 2001, AJ, 122, 2833

44. The First 7 Billion Years M81 by Spitzer

45. Distant Galaxies are “Train Wrecks” Trace construction of Hubble sequence: How do “train wrecks” become spirals and ellipticals? By Merging!

46. Galaxy Mergers

47. The Last 7 Billion Years

49. The Next 20 Years What is the cause of inflation? What is the dark energy? How did the Universe begin? How will it end? In other words:

50. Can We Prove Inflation? Gravity waves propagating during inflation leave a mark on the polarization of the CMB. CMB Polarization mission –Currently being studied.

51. What is the Dark Energy? Hypothesized by Einstein, discovered in 1998, confirmed in 2003. 3 potential Nobel Prizes: –Cosmological Constant breaks standard model of particle physics –Quintessence means new physics –Modification of General Relativity NASA-DOE Joint Dark Energy Mission –Currently being studied.

52. Observational Cosmology Jonathan P. Gardner NASA’s Goddard Space Flight Center