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SUMMARY:The angular size of the Sun and Moon and the emergence of Devonian
  tetrapods - Professor Steve Balbus (Oxford)
DTSTART:20140207T113000Z
DTEND:20140207T123000Z
UID:TALK50492@talks.cam.ac.uk
CONTACT:Simon Hodgkin
DESCRIPTION:*ABSTRACT*\n\nThe very similar angular sizes of the Sun and Mo
 on as subtended at the Earth is generally regarded as coincidental.  In fa
 ct\, it is a simple mathematical consequence of even roughly comparable lu
 nar and solar tidal amplitudes.   I will present a case for why the latter
  may have been a biological imperative.  The key point is that comparable 
 tidal amplitudes sharing very close\, but distinct\, Doppler-shifted forci
 ng frequencies leads to strongly modulated equilibrium tides.  These tides
  should be viewed in the context of reconstructions of Late Devonian conti
 nental land masses which suggest a broad western opening to the Iapetus Oc
 ean that tapers to a more narrow\, shallow-sea strait between Laurasia and
  Gondawana. The combination of this geography with strongly modulated tida
 l forcing may well have been conducive to a particularly rich\, penetrativ
 e network of shallow tidal pools at the epoch when tetrapods were making t
 heir amphibian transition.  A. S. Romer's classic vision of stranded aquat
 ic tetrapods forced to scramble seaward by evaporating inland pools may be
  supported not by arid conditions (as once envisaged)\, but by the ancient
  astronmomical observation that\nthe Sun and Moon have the same angular si
 ze when viewed from the\nEarth.
LOCATION:Kavli Large Meeting Room\, Kavli Building
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