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SUMMARY:Tales of gravity from few-body interactions - Dr. Hongsheng Zhao\,
  University of St Andrews
DTSTART:20211130T193000Z
DTEND:20211130T204500Z
UID:TALK163120@talks.cam.ac.uk
CONTACT:Xuchen Wang
DESCRIPTION:Our understanding of gravity started with analysis of motions 
 of solar system bodies\, as interpreted by Newton and Einstein. When we go
  further away from the solar system\, gravity takes on a less familiar emp
 irical relation\, which is sometimes phrased as evidences either for physi
 cs dark matter particles or for Modified Newtonian gravity.  Even with 100
 % knowledge of the present position and velocity of every star in the univ
 erse\, we still cannot predict the acceleration of each star\, ie\, the po
 sition and velocity of each star next year.    If gravity were modified\, 
 then it would take three universal parameters to describe the acceleration
 : G\, c\, and the cosmological constant Lambda. If the added gravity were 
 due to dark particles\, then a full description of acceleration would take
  2+Infinity parameters: G\, c\, and a spatially fluctuating dark-to-lumino
 us ratio everywhere.  \n\nFortunately a distinction can be made about thes
 e two flavors of interpretations in the cases of interactions in binary or
  triple systems\, e.g.\, the Milky Way -Andromeda system\, the wide binary
  of stars in our Galaxy. 
LOCATION:Pfizer Lecture Theatre\, Department of Chemistry
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