1. (A few) Basic Topical Concepts in Cosmology Emili Elizalde Institut de Ciències de l’Espai (ICE/CSIC) Institut d’Estudis Espacials de Catalunya (IEEC) Campus Universitat Autònoma de Barcelona (UAB) Bellaterra Lunch-Pizza Seminar, 16 March 2012

3. But... the Universe was static !! (…and very small) But... the Universe was static !! (…and very small) What is λ ? Non-physical What is λ ? Non-physical At that time: UNIVERSE = MILKY WAY (+ nebulae) At that time: UNIVERSE = MILKY WAY (+ nebulae) Ptolemy 150 DC, Almagest: mentions 5 nebulae Ptolemy 150 DC, Almagest: mentions 5 nebulae Persian, Arabic, Chinese astronomers: more nebulae Persian, Arabic, Chinese astronomers: more nebulae Edmund Halley 6 in 1715, Charles Messier 103 in 1781 Edmund Halley 6 in 1715, Charles Messier 103 in 1781 William and Caroline Herschel 3 catalogs, 1786-1802, a total of 2510 nebulae William and Caroline Herschel 3 catalogs, 1786-1802, a total of 2510 nebulae And then, Edwin Hubble, in 1922-1924, saw Andromeda nebulae (.8 Mly) was far beyond our Milky Way: nebulae were other galaxies! And then, Edwin Hubble, in 1922-1924, saw Andromeda nebulae (.8 Mly) was far beyond our Milky Way: nebulae were other galaxies! Henrietta S Leavitt (Ed Pickering’s Harvard Harem), ‘12 period-luminosity relationship of Cepheid variable stars (Eddington, He +,++ ) Hertzsprung-Russell Diagramm Henrietta S Leavitt (Ed Pickering’s Harvard Harem), ‘12 period-luminosity relationship of Cepheid variable stars (Eddington, He +,++ ) Hertzsprung-Russell Diagramm

4. Henrietta Leavitt Ed Pickering’s Harvard Harem … or Harvard Computers 1913 Mittag-Leffler NP proposal ‘26

8. Karl Schwarzschild: Black Hole solution (22 Dec 1915) Karl Schwarzschild: Black Hole solution (22 Dec 1915) Willem de Sitter: massless univer static sol (just cc,’17) Willem de Sitter: massless univer static sol (just cc,’17) Alexander Friedmann: expanding universe sol (1922) Alexander Friedmann: expanding universe sol (1922) Georges Lemaître: expanding universe (MIT 1925, AF solution); visited Vesto Slipher (Lowell Obs, Arizona, 1912 redshifts) and Edwin Hubble (Mount Wilson, Pasadena); Keeler-Slipher-Campbell, 1918 Georges Lemaître: expanding universe (MIT 1925, AF solution); visited Vesto Slipher (Lowell Obs, Arizona, 1912 redshifts) and Edwin Hubble (Mount Wilson, Pasadena); Keeler-Slipher-Campbell, 1918 Led to Big Bang theory (Fred Hoyle, BBC radio 3 rd Programme, 18:30 GMT, 28 March 1949) Led to Big Bang theory (Fred Hoyle, BBC radio 3 rd Programme, 18:30 GMT, 28 March 1949) Fred Hoyle, Thomas Gold, Hermann Bondi: SteadyState ’48, “C-field” with a negative pressure, to be consistent with energy conservation (anticipated inflation) Fred Hoyle, Thomas Gold, Hermann Bondi: SteadyState ’48, “C-field” with a negative pressure, to be consistent with energy conservation (anticipated inflation) Friedmann-Lemaître-Robertson-Walker (FLRW 1931-37) Friedmann-Lemaître-Robertson-Walker (FLRW 1931-37) A Riess B Schmidt ’98, S Perlmutter ’99: acceler expan! A Riess B Schmidt ’98, S Perlmutter ’99: acceler expan!

9. Friedmann equation (matter,radiation,curvature) Multiply by a 2 to get When a increases, each term on rhs decreases: the universe should be decelerating (a decreases). a t Big Bang Sean Carroll, Caltech SSI 2009

10. Two groups looked for the ‘deceleration’ of the universe expansion, using type Ia supernovae as standardizable candles SN 1994d

11. Result: supernovae are dimmer than expected The universe is not decelerating It is accelerating Cannot be explained by matter+radiation (see before) Riess, Schmidt et al. ‘98 Perlmutter et al. ‘99

14. (from S.Reynaud)

27. Some Books 2 nd Ed June 2012

28. Thank You Moltes Gràcies Dank je wel