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PRODID:UW-Madison-Physics-Events
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SEQUENCE:0
UID:UW-Physics-Event-1488
DTSTART:20090312T203000Z
DURATION:PT1H0M0S
DTSTAMP:20260420T041759Z
LAST-MODIFIED:20090309T164050Z
LOCATION:2103 Chamberlin Hall
SUMMARY:A brief History of Cosmic Expansion and Acceleration\, Whitfor
 d Lecture\, Adam Riess\, JHU and STSci
DESCRIPTION:<br><br>
\nThe expansion rate and its evolution must be em
 pirically determined for our Universe to reveal its composition\, scal
 e\, age\, and fate. In 1998\, high-redshift SNe Ia provided the first 
 and only direct evidence for an accelerating Universe and the existenc
 e of dark energy. To identify the nature of dark energy we seek to imp
 rove on past and present measurements of the recent history of cosmic 
 expansion. Today's keystones of expansion are distant type Ia supernov
 ae and Cepheid variables in their hosts. I will report on new calibrat
 ions of the Hubble diagram of SNe Ia with new SN Ia and Cepheid data a
 nd an extension of its reach to <br><br>
\nz &gt\; 1 when cosmic expan
 sion was still decelerating. These measurements are providing new clue
 s about the nature of the mysterious dark energy.<br><br>
\n<br><br>
\
 n
URL:https://www.physics.wisc.edu/events/?id=1488
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