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(A few ) Basic Topical Concepts in Cosmology

(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.

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(A few ) Basic Topical Concepts in Cosmology

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  1. (A few) BasicTopicalConceptsin Cosmology EmiliElizalde Institut de Ciències de l’Espai (ICE/CSIC) Institutd’EstudisEspacials de Catalunya (IEEC) Campus UniversitatAutònoma de Barcelona (UAB) Bellaterra Lunch-Pizza Seminar, 16 March2012

  2. But... the Universe was static !! (…and very small) • Whatisλ ? Non-physical • At that time: UNIVERSE = MILKY WAY (+ nebulae) • Ptolemy 150 DC, Almagest:mentions5nebulae • Persian, Arabic, Chinese astronomers: more nebulae • Edmund Halley 6 in 1715, Charles Messier103 in 1781 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! • Henrietta S Leavitt(EdPickering’s Harvard Harem), ‘12 period-luminosityrelationshipof Cepheid variable stars (Eddington , He+,++) Hertzsprung-RussellDiagramm

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

  4. Karl Schwarzschild: Black Holesolution (22 Dec 1915) • Willem de Sitter: masslessuniverstatic sol (just cc,’17) • Alexander Friedmann: expandinguniverse sol (1922) • Georges Lemaître: expanding universe (MIT 1925, AF solution); visited VestoSlipher(Lowell Obs, Arizona, 1912 redshifts) and Edwin Hubble(Mount Wilson, Pasadena); Keeler-Slipher-Campbell, 1918 • Led to Big Bang theory (Fred Hoyle, BBC radio 3rdProgramme, 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 (anticipatedinflation) • Friedmann-Lemaître-Robertson-Walker (FLRW 1931-37) • A Riess B Schmidt ’98, SPerlmutter ’99: accelerexpan!

  5. Multiply by a2 to get When a increases, each term on rhs decreases: the universe should be decelerating (a decreases) . Friedmann equation (matter,radiation,curvature) a Sean Carroll, Caltech SSI 2009 Big Bang t

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

  7. 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

  8. (fromS.Reynaud)

  9. SomeBooks 2nd Ed June 2012

  10. ThankYouMoltes GràciesDank je wel

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