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PRODID:UW-Madison-Physics-Events
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UID:UW-Physics-Event-4663
DTSTART:20171019T203000Z
DTEND:20171019T220000Z
DTSTAMP:20260418T001112Z
LAST-MODIFIED:20171010T194829Z
LOCATION:4421 Sterling Hall\, Coffee and cookes 3:30 PM. Talk begins a
 t 3:45 PM
SUMMARY:Climate Cycles and the History of Our Solar System\, Astronomy
  Colloquium\, Stephen Meyers\, Department of Geoscience\, UW Madison
DESCRIPTION:Quasiperiodic variations in Earth’s orbit and spin vecto
 r influence the distribution of sunlight on Earth’s surface\, causin
 g cyclic climate change on time scales >10\,000 years.  The geologic r
 ecord preserves evidence of these astronomical-climate rhythms\, which
  are expressed as physical\, chemical and paleobiologic variability in
  sedimentary strata.  In this seminar\, I will discuss how these “fo
 ssilized” astronomical signals can be used to test hypotheses about 
 the behavior of the Solar System\, and its evolution over the past sev
 eral billion years.  One of the most fundamental questions that we can
  address with the geological archive pertains to the proposed chaotic 
 dynamical nature of the Solar System that is predicted by numerical an
 d analytical models of the planetary orbits.  New geological data from
  the Cretaceous period (~86 million years ago) provides the first unam
 biguous confirmation of this chaotic motion.  Another question that th
 e geologic record is uniquely poised to address is the history of the 
 Earth-Moon system\, including changes in Earth-Moon separation and len
 gth of day.  To address this research problem\, I will present results
  from a new Bayesian inversion approach that uses the astronomical sig
 nals preserved in very ancient strata (> 1 billion years old) to recon
 struct the Earth-Moon history\, as well as the fundamental frequencies
  of the Solar System.  A byproduct of this work is the development of 
 high-resolution geological time scales that can be used to assess rate
 s of Earth system processes\, including climate change and biological 
 evolution.  Taken together\, these examples highlight the close interl
 ink between geology and astronomy\, and how these fields can fundament
 ally inform each other.
URL:https://www.physics.wisc.edu/events/?id=4663
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