Download presentation
Presentation is loading. Please wait.
Published byRosanna Austin Modified over 8 years ago
1
Cosmology, 2010 1 1 Cosmology I & II Fall 2010
2
Cosmology, 20102 Cosmology I & II Cosmology I: 7.9.-22.10. Cosmology II: 1.11.-17.12. http://theory.physics.helsinki.fi/~cosmology http://theory.physics.helsinki.fi/ Lectures in A315, Mon & Tue 14.15-16.00 Syksy Räsänen, C326, syksy.rasanen@iki.fi Exercises in D112, Fri 14.15-16.00 (starting 17.9.) Stanislav Rusak, A314, stanislav.rusak@helsinki.fi Exercises form 20% of the score, the exam 80% Exercises are handed out on Monday, and returned by following Monday. Exception: next week they are due on Wednesday. Cosmology I: 7.9.-22.10. Cosmology II: 1.11.-17.12. http://theory.physics.helsinki.fi/~cosmology http://theory.physics.helsinki.fi/ Lectures in A315, Mon & Tue 14.15-16.00 Syksy Räsänen, C326, syksy.rasanen@iki.fi Exercises in D112, Fri 14.15-16.00 (starting 17.9.) Stanislav Rusak, A314, stanislav.rusak@helsinki.fi Exercises form 20% of the score, the exam 80% Exercises are handed out on Monday, and returned by following Monday. Exception: next week they are due on Wednesday.
3
Cosmology, 20103 Cosmology I Introduction Basics of general relativity Friedmann-Robertson-Walker (FRW) models Thermal history of the universe Big Bang nucleosynthesis (BBN) Dark matter Introduction Basics of general relativity Friedmann-Robertson-Walker (FRW) models Thermal history of the universe Big Bang nucleosynthesis (BBN) Dark matter
4
Cosmology, 20104 Cosmology II Quantum field theory (QFT) for children Inflation Structure formation Brief introduction to perturbation theory Cosmic microwave background (CMB) anisotropy Quantum field theory (QFT) for children Inflation Structure formation Brief introduction to perturbation theory Cosmic microwave background (CMB) anisotropy
5
Cosmology, 20105 Observations: basics Electromagnetic radiation Radio waves Microwaves IR Visible light UV X-Rays Gamma rays Massive particles Cosmic rays (protons, antiprotons, heavy ions, electrons, antielectrons) Neutrinos Gravity waves? Composition of the solar system Electromagnetic radiation Radio waves Microwaves IR Visible light UV X-Rays Gamma rays Massive particles Cosmic rays (protons, antiprotons, heavy ions, electrons, antielectrons) Neutrinos Gravity waves? Composition of the solar system
6
Cosmology, 20106 Observations in practice Motion of galaxies Distribution of galaxies (large scale structure) Abundances of light elements Cosmic microwave background Luminosities of distant supernovae Number counts of galaxy clusters Deformation of galaxy images (cosmic shear) ... Motion of galaxies Distribution of galaxies (large scale structure) Abundances of light elements Cosmic microwave background Luminosities of distant supernovae Number counts of galaxy clusters Deformation of galaxy images (cosmic shear) ...
7
Cosmology, 20107 Laws of physics General relativity Quantum quantum field theory Atomic physics, nuclear physics, the Standard Model of particle physics Statistical physics and thermodynamics General relativity Quantum quantum field theory Atomic physics, nuclear physics, the Standard Model of particle physics Statistical physics and thermodynamics
8
Cosmology, 20108 Homogeneity and isotropy: observations http://map.gsfc.nasa.gov/media/101080/index.html
9
Cosmology, 20109 Homogeneity and isotropy: observations http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=47333
10
Cosmology, 201010 Homogeneity and isotropy: observations arXiv:astro-ph/0604561, Nature 440:1137.2006
11
Cosmology, 201011 Homogeneity and isotropy: observations
12
Cosmology, 201012 Homogeneity and isotropy: theory The observed statistical homogeneity and isotropy motivates theory with exact H&I The Friedmann-Robertson-Walker models The expansion of the universe is described by the scale factor a(t) Extrapolating the known laws of physics we find that 14 billion years ago a → 0, ρ → ∞, T → ∞ The observed statistical homogeneity and isotropy motivates theory with exact H&I The Friedmann-Robertson-Walker models The expansion of the universe is described by the scale factor a(t) Extrapolating the known laws of physics we find that 14 billion years ago a → 0, ρ → ∞, T → ∞
13
Cosmology, 201013 The Big Bang The early universe was Hot Dense Rapidly expanding H&I and thermal equilibrium ⇒ easy to calculate High T ⇒ high energy ⇒ quantum field theory The early universe was Hot Dense Rapidly expanding H&I and thermal equilibrium ⇒ easy to calculate High T ⇒ high energy ⇒ quantum field theory
14
Cosmology, 201014 Timeline of the universe 10 -12 s 10 -6 s 1 s 1 h TeV GeV MeV Electroweak (EW) transition Fermions, W +,W -,Z 0 become massive g massless Baryogenesis? QCD phase transition: quarks p, n ν decoupling e + e - annihilation n/p ≈ 1/6 Big bang nucleosynthesis (BBN) 2 H, 3 He, 4 He, 7 Li
15
Cosmology, 201015 Short history of the universe 1 yr 10 6 yr 10 10 yr Now keV eV meV Decoupling of light and baryons => atoms The universe becomes transparent Cosmic Microwave background (CMB) Structure formation Formation of galaxies, first stars Dark ages
16
Cosmology, 201016 Short history of the universe 10 -42 s 10 19 GeV Planck time GUT era? Baryogenesis? Topological defects formed? (monopoles, cosmic strings, domain walls) Supersymmetry breaks? 10 -36 s 10 -30 s 10 -12 s 10 -24 s 10 -18 s 10 15 10 12 10 9 10 18 10 6 10 3 GeV Inflation? SU(3) SU(2) U(1)
17
Cosmology, 201017 Structure formation CMB shows the initial conditions The early universe is exactly homogeneous up to small perturbations of 10 -5 to 10 -3 Seeds of structure Gravity is attractive ⇒ fluctuations grow into galaxies, clusters of galaxies, filaments, walls and voids, which form the large-scale structure of the universe CMB shows the initial conditions The early universe is exactly homogeneous up to small perturbations of 10 -5 to 10 -3 Seeds of structure Gravity is attractive ⇒ fluctuations grow into galaxies, clusters of galaxies, filaments, walls and voids, which form the large-scale structure of the universe
18
Cosmology, 201018
19
Cosmology, 201019
20
Cosmology, 201020
21
Cosmology, 201021 Structure formation Origin of fluctuations: inflation A period of acceleration in the early universe Quantum fluctuations are stretched by the fast expansion and frozen in place Growth of fluctuations Due to ordinary gravity Depends on the initial state plus the matter composition Baryonic matter is too smoothly distributed at last scattering Origin of fluctuations: inflation A period of acceleration in the early universe Quantum fluctuations are stretched by the fast expansion and frozen in place Growth of fluctuations Due to ordinary gravity Depends on the initial state plus the matter composition Baryonic matter is too smoothly distributed at last scattering
22
Cosmology, 201022 Dark matter Luminous matter: stars, gas (plasma), dust Large-scale structure, CMB anisotropies, motions of stars in galaxies, galaxies and gas in clusters, gravitational lensing, BBN,... ⇒ there is invisible matter Baryonic matter: cold and hot gas, brown dwarfs However, the majority of matter (about 80%) is non-baryonic, either cold dark matter (CDM) or warm dark matter (WDM, m > 10 keV) Neutralinos, technicolor dark matter, right- handed neutrinos,... Luminous matter: stars, gas (plasma), dust Large-scale structure, CMB anisotropies, motions of stars in galaxies, galaxies and gas in clusters, gravitational lensing, BBN,... ⇒ there is invisible matter Baryonic matter: cold and hot gas, brown dwarfs However, the majority of matter (about 80%) is non-baryonic, either cold dark matter (CDM) or warm dark matter (WDM, m > 10 keV) Neutralinos, technicolor dark matter, right- handed neutrinos,...
23
Cosmology, 201023 Dark energy Exactly homogeneous and isotropic models with baryonic and dark matter don’t quite agree with the observations Measured distances are longer by a factor of 1.4-1.7 and the expansion is faster than predicted by a factor of 1.5-2 Three possibilities: 1) There is matter with negative pressure which makes the universe expand faster (dark energy) 2) General relativity does not hold (modified gravity) 3) The homogeneous and isotropic approximation is not good enough Exactly homogeneous and isotropic models with baryonic and dark matter don’t quite agree with the observations Measured distances are longer by a factor of 1.4-1.7 and the expansion is faster than predicted by a factor of 1.5-2 Three possibilities: 1) There is matter with negative pressure which makes the universe expand faster (dark energy) 2) General relativity does not hold (modified gravity) 3) The homogeneous and isotropic approximation is not good enough
24
Cosmology, 201024 Dark energy Dark energy is the preferred option Dark energy has large negative pressure is smoothly distributed has an energy density about three times that of baryonic plus dark matter The most natural candidate is vacuum energy “The greatest mystery in physics.” Dark energy is the preferred option Dark energy has large negative pressure is smoothly distributed has an energy density about three times that of baryonic plus dark matter The most natural candidate is vacuum energy “The greatest mystery in physics.”
Similar presentations
© 2024 SlidePlayer.com Inc.
All rights reserved.