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PRODID:UW-Madison-Physics-Events
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SEQUENCE:0
UID:UW-Physics-Event-9662
DTSTART:20260430T000000Z
DTEND:20260430T013000Z
DTSTAMP:20260425T003806Z
LAST-MODIFIED:20260417T120856Z
LOCATION:1310 Sterling Hall
SUMMARY:Whitford Public Talk: The Mysteries of Cosmic Dust\, Astronomy
  Colloquium\, Bruce Draine\, Princeton University
DESCRIPTION:The first galaxies form stars out of initially pristine ga
 s.  After a<br>\nfew million years the gas is enriched with heavy ele
 ments formed by<br>\nthe first generation of stars.  Dust starts to a
 ppear in small<br>\namounts\, and H2 formation by catalysis on dust gr
 ains begins.<br>\n<br>\nJWST Spectroscopy of I Zw 18\, a very metal-po
 or star-forming galaxy in<br>\nthe nearby universe\, provides an oppor
 tunity to study these<br>\nbeginnings.  The composition of the first 
 dust is found to be very<br>\ndifferent from dust in a mature galaxy s
 uch as the Milky Way.  The<br>\nmolecular hydrogen emission spectrum 
 allows the ortho/para ratio to be<br>\ndetermined\, with the ortho/par
 a ratio found to exceed 3 in some regions.<br>\nImplications will be d
 iscussed.
URL:https://www.physics.wisc.edu/events/?id=9662
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