1. 现代宇宙学概论 郭宗宽 武汉大学物理科学与技术学院 2013.11.22

2. 内容 一．什么是宇宙 二．宇宙学进展 三．宇宙的组成物质 四．宇宙的演化 五．现代宇宙学中存在的问题

3. 一. 什么是宇宙 宗教与宇宙观 Aristotle (384~322 BC) 尸子：四方上下谓之宇，古往今来谓之宙 老子：道生一、一生二、二生三、三生万物 易传：太极生两仪，两仪生四象，四象生八卦 基督教，伊斯兰教， … The earth was a stable object around which the Sun, Moon and other planets revolved.

4. Claudius Ptolemy (90~168 AD) Nicolaus Copernicus (1473~1543) Johannes Kepler (1571~1630) Each planet moved in a circle called an epicycle, whose center was in turn carried around the earth in a second circular orbit called a deferent. The planets revolve around the sun and that the Sun, not the Earth, was the center of our Universe. The planets revolved around the sun in elliptical, as opposed to circular orbits and gave us the means for calculating their individual distance from the Sun.

5. Galileo Galilei (1564~1642) Sir Isaac Newton (1642~1727) He developed a series of telescopes, observed the Milky Way, and found it to be a multitude of tiny stars. He formulated the law of universal gravitation. Universal gravitation states that all objects are effected by a force, gravity, and that the strength of this force varies in accordance to the mass and distance between the objects.

6. Edwin Powell Hubble (1889~1953) He proved that many formerly known "nebulae" were actually galaxies beyond the Milky Way and determined that these other galaxies were moving away from us and each other. Hubble’s law:

7. 太阳大，地球小，地球绕着太阳跑。 地球大，月亮小，月亮绕着地球跑。

8. ObjectMass (M ⊙ )Size stars1 star clusters100 pc galaxies 1  50 kpc galaxy groups1 Mpc galaxy clusters3 Mpc superclusters10 Mpc LSS 10  100 Mpc voidsuncertain 10  100 Mpc observable Universe4 Gpc Cosmological Ladders

9. 玉夫座 银河系 室女座 大熊座狮子座 天炉座 牧夫座 长蛇座 蛇夫座 半人马座 啥普利座 后发座 矩尺座 天鸽座 猎户座 金牛座 阿贝尔座 武仙座 北冕座 英仙座双鱼座 鲸鱼座 孔雀座印第安座 时钟座

10. The Andromeda Galaxy (M31): 10^10 stars, 2*10^6 ly away from our galaxy

11. Triangulum Galaxy (M33): 10^11 stars, 3*10^6 ly away from our galaxy

12. Orion Molecular cloud

13. Apr 273 UGC1 810 UGC1 813 This Hubble image is a composite of data taken with three separatefilters on WFC3 that allow a broad range of wavelengths coveringthe ultraviolet, blue, and red portions of the spectrum.

14. 天体质量半径表面引力 太阳 11 白矮星 < 1.4 中子星 1~3 黑洞 > 31 引力塌缩和致密星

15. X-rayultravioletoptical infrared The composite image of Arp 147: Chandra X-ray data (pink), Hubble optical data (red, green and blue), ultraviolet GALEX data (green) and infrared Spitzer data (red). http://chandra.harvard.edu/photo/2011/arp147/more.html composite

16. X-rayultravioletoptical infrared The composite image of the Cartwheel Galaxy: Chandra X-ray data (purple), ultraviolet GALEX data (blue), Hubble optical data (green) and infrared Spitzer data (red). http://chandra.harvard.edu/photo/2006/cartwheel/more.html composite

17. 宇宙学观测 — 电磁波 波段观测实验未来项目 RadioVLA, SKA, FAST, LOFAR CMBCOBE, WMAP, Planck InfraredWISE, SpitzerWFIRST (mid-2020s) OpticalHubble, 2dFGRS, SDSS, CSTAREuclid, LSST UltravioletGALEX X-rayChandra, XMM-Newton Gamma-rayFermi LAT, H.E.S.S.

18. 宇宙学观测 — 其他窗口 窗口观测实验未来项目 Cosmic rayPAMELA, Fermi, AMS-02 Gravitational waveLIGO, Virgo, AIGOLISA Cosmic neutrino

19. 二. 宇宙学进展 Cosmological principle: The Universe is homogeneous and isotropic on large scales.

20. The geometry of the Universe Euclidean geometry (k = 0, a flat Universe): the angles of a triangle add up to 180º, the circumference of a circle of radius r is 2  r, parallel line never meet spherical geometry (k > 0, a closed Universe): a finite size but no boundary hyperbolic geometry (k < 0, a open Universe)

21. 1. 热大爆炸模型（ 1920s  1970s ） – 宇宙在膨胀（ 1929 ） –BBN 的预言与观测一致（ 1998 ） –CMB 的黑体谱（ 1994 ） 2. 标准宇宙学模型（ 1980s  2000s ） – 暴胀 +Λ+ 冷暗物质 + 重子 + 中微子 3. 精确宇宙学时代（ 2000s  now ） –CMB, LSS(BAO, GC, WL), SNIa – 宇宙学不再是个传说

22. 1. 热大爆炸模型（ 1920s  1970s ）

23. 1915, general relativity established by Albert Einstein

24. 1922, Alexander Friedmann found solutions for an expanding Universe. 1929, Edwin Powell Hubble discovered the expansion of the Universe. 1940s, Hot Big Bang (George Gamow)

25. 1940s-1960s, BBN, the origin of the light elements, was completed.

27. 1965, CMB radiation was discovered by Arno Penzias and Robert Wilson. Nobel Prize in Physics 1978

28. Four pieces of evidence for Hot Big Bang ① the expansion of galaxies ② the existence of the CMB radiation ③ the abundances of light elements predicted by BBN ④ the age of the oldest stars (  13 Gyr )

29. 2. 标准宇宙学模型（ 1980s  2000s ）

30. 1981, inflation proposed by Alan Guth Problems with the Hot Big Bang ① the flatness problem ② the horizon problem ③ relic particle abundances V (φ) φ inflation reheating

32. 1989-1993, Cosmic Background Explorer (COBE), NASA J.C. Mather G.F. Smoot (DMR) Hot big bangisotropy Nobel Prize in Physics 2006

33. 1997-2002, the Two-degree-Field Galaxy Redshift Survey (2dFGRS)

34. 1998, the discovery of the accelerating expansion of the Universe The Nobel Prize in Physics 2011 was divided, one half awarded to Saul Perlmutter (leader of SCP), the other half jointly to Brian P. Schmidt (leader of High-Z) and Adam G. Riess (High-Z) "for the discovery of the accelerating expansion of the Universe through observations of distant supernovae". A.G. Riess et al., Astron. J. 116 (1998) 1009 [arXiv:astro-ph/9805201] S. Perlmutter et al., Astrophys. J. 517 (1999) 565 [arXiv:astro-ph/9812133] Saul PerlmutterAdam G. RiessBrian P. Schmidt Nobel Prize in Physics 2011

35. Type Ia supernovae are thought to result when a white dwarf star in a binary system accumulates enough matter from its larger companion. When the white dwarf reaches the critical Chandrasekhar mass, about 1.4 times the mass of our sun, high internal density and temperature ignite a thermonuclear explosion. Because the masses of Type Ia supernovae are similar, their brightnesses are similar.

36. other evidences for cosmic acceleration BAO CMB

37.  The simplest model: cosmological constant ① Fine-tuning problem ② Coincidence problem  Dynamical models: quintessence, cosmic axion, tracker fields, spintessence, k- essence, ghost condensate, coupled dark energy, phantom dark energy, …  Modified gravity: scalar-tensor theory, f(R) gravity, Chameleon model, DGP, massive gravity, …  Parameterizations: constant w, CPL, Chaplygin gas, …  Inhomogeneous model: LTB model, backreaction of perturbations  Anthropic principle: landscape

38. Six-parameter standard cosmological model ① Baryon density today ② Cold dark matter density today ③ Cosmological constant density ④ Optical depth to reionization ⑤ Scalar spectral index ⑥ Amplitude of the primordial curvature perturbations

39. 3. 精确宇宙学时代（ 2000s  now ）

40. 2000-now, The Sloan Digital Sky Survey (SDSS)  2000-2005, SDSS-I  2005-2008, SDSS-II  2008-2014, SDSS-III

41. 2001-2010, Wilkinson Microwave Anisotropy Probe (WMAP), NASA 141°

42. free-free emission: electron-ion scattering synchrotron emission: the acceleration of cosmic ray electrons in magnetic fields thermal emission from dust 23 GHz 33 GHz 41 GHz 61 GHz 94 GHz

43. angular power spectrum of CMB foreground mask

44. a)2003, WMAP1, 14 papers, cited by 6873 records b)2007, WMAP3, 5 papers, cited by 5289 records c)2009, WMAP5, 8 papers, cited by 3527 records d)2011, WMAP7, 6 papers, cited by 3803 records e)2012, WMAP9, 2 papers, cited by 303 records WMAP science team publications We have entered a new era of precision cosmology.

45. 2009, 30 months, Planck, ESA LFI: 30,44,70 GHz HFI : 100,143,217,353,545,857 GHz high sensitivity wide frequency full-sky coverage high resolution ~7º,15′,5′

47. the TT spectrum cosmological parameters 20 March 2013, 29 papers

48. Precision Cosmology

49. 三. 宇宙的组成物质  dark energy  dark matter  baryon  photon  neutrinos  gravitational wave

50. Observational evidences for dark matter bullet clusters rotation curve N-body simulation CMB anisotropies gravitational lensingType Ia supernovae

51. LISA LIGO Livingston LIGO Hanford Virgo Pulsar timing CMB AIGO Gravitational wave detector

52. 四. 宇宙的演化  initial singularity  inflation  baryogenesis  phase transition  nucleosynthesis  radiation-matter eq.  matter-dominated  recombination  structure formation  current acceleration

53. 五. 现代宇宙学中存在的问题 1. 宇宙暴胀的本质 2. 重子不对称的起源 3. 宇宙暗物质的本质 4. 宇宙目前的加速膨胀 5. 宇宙的奇点（量子引力） 6. 中微子的质量 7. 引力波的探测

54. 谢谢！