AST 115 1st Edition Lecture 35 Outline of Last Lecture I. Intro to CosmologyII. Observational Cosmologya. Olbers’ Paradoxb. Expanding Universei. The important implications of an expanding universec. Quasar Censusd. Cosmic (Microwave) Background Radiation (CMB)Outline of Current Lecture I. Cosmic (microwave) Background Radiation [CMB] continueda. COBEb. WMAPII. Theoretical Cosmologya. Cosmological Principalb. Perfect Cosmological Principali. Steady-State Theoryii. String TheoryCurrent Lecture Cosmic (microwave) Background Radiation [CMB] continued…o The COBE (Cosmic Background Explorer) A satellite in 1990 measured the CMB more precisely and showed a perfect fit to the theory.o Results from the WMAP (Wilkinson Microwave Anisotrophy Probe) indicate that the age of the universe is 13.8 BY (plus/minus 0.2 BY). Detailed analysis of the patterns in the CMB gives the time at which the universe became transparent to radiation as 380,000 years (plus/minus 8,000 years).These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute. The WMAP results show the following make-up of the universe:- 23.2% Dark Matter- 72.2% Dark Energy- 4.6% other (neutrinos 0.10%, normal matter 4.5%, electromagnetic radiation 0.005%). Theoretical Cosmologyo Cosmological Principle The universe must look the same to any observer. If a Hubble-Creature located at 3C 48 made similar measures, it would get the same result as our Hubble did. Corollary: Laws of physics are the same throughout the universe.o Perfect Cosmological Principle The universe must look the same to any observer and for all time. This ledin the 1950’s to the Steady-State theory. The Steady-State Theory: the universe has always existed and will always exist.- In order to account for expansion, this theory requires that matterform in the voids at the right rate to produce new galaxies, etc. to keep the universe looking the same to all at all times. - Evidence of evolution of the universe and the discovery of CMB killed this theory. String Theory- The ultimate framework of the university may consist of vibrating one-dimensional units known as “strings”. This is a developing field of theoretical cosmology, which in part predicts the existenceof an additional 7 space dimensions and time for a total of 11.- Don’t know if this theory has physical basis, but it is encouraging anew direction for explaining features of the
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