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Unformatted text preview: and those galaxies are now calculated to be about 46 billion lightyears from us. [ citation needed ] To estimate the distance to that matter at the time the light was emitted, we may first note that according to the Friedmann–Lemaître–Robertson–Walker metric which is used to model the expanding universe, if at the present time we receive light with a redshift of z , then the scale factor at the time the light was originally emitted is given by the equation . [19] [20] WMAP sevenyear results give the redshift of photon decoupling as z =1090.89 [17] which implies that the scale factor at the time of photon decoupling would be . So if the matter that originally emitted the oldest CMBR photons has a present distance of 46 billion light years, then at the time of decoupling when the photons were originally emitted, the distance would have been only about 42 million lightyears away....
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This note was uploaded on 12/15/2011 for the course AST AST1002 taught by Professor Emilyhoward during the Fall '10 term at Broward College.
 Fall '10
 EmilyHoward
 Astronomy

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