CHANDRASEKHAR CENTENARY LECTURE

Title: From white  dwarfs  to  holography and quantum gravity


Date: 19th Oct, 4:00pm, CHEP Seminar Hall (IISC)


Abstract:
The talk aims to trace the influence of the Chandrasekhar limit
in  understanding  the physics of gravity. Here
is a summary of the salient points which will be covered
in the talk.


Around the time when Chandrasekhar was born ,
the white dwarf  was regarded  as  a bete noir by  astronomers.  During
1930-35 , Chandrasekhar proved that massive stars which have
run out their fuel , can not rest in peace as white dwarfs if their mass
exceeds 1.44 times the mass of the Sun , because  gravitation will
overwhelm all other forces and they  must collapse.
Recalling later developments, in  1982  during the Eddington centenary
lecture  Chandrasekhar said " the existence  for a limiting mass   is
inextricably woven into the present fabric of astronomical tapestry with
its complex designs of stellar evolution , nuclear burning in the
 high - density cores of certain stars  and gravitational collapse
leading to supernova phenomenon and the formation of neutron  stars of
nearly the same mass and of black holes. " .

In the  nineteen thirties  famous but older physicists  disliked the idea
of ultimate  collapse and disapproved of singularities of the equations of
physics. Along with the issue of stellar collapse there was also the
parallel  problem  regarding cosmological singularities present   in
models of the Universe . Are singularities rigorous results of equations
of physics or the work of maladroit  theorist  ?  The seminal  work of
Raychaudhuri  in the fifties , paved the way for Penrose  Hawking  and
Geroch , to prove a decade later
-1) the inevitability for collapse  into black hole  by a massive  star
on the one hand
2)  strengthened  the basis of big bang cosmology on the other . It is
consistent with astronomical data  to  assume that our  Universe
began with a singularity  .

Today thousands of white dwarfs with mass below Chandrasekhar limit are
known with their structure and properties well understood . They are an
important standard in astronomy.  Many stellar mass black holes are known
today.

Classical black holes absorb everything and  pose a problem for the second
law of thermodynamics .  Hawking's  discovery that in quantum theory ,
black holes must radiate  resolves this  but brings in fresh issues in its
wake  , challenging our  understanding of interface
between the inside and  outside of  a black hole .

Speaker: J. Pasupathy.
Affiliation: CHEP



I think we should all attend this lecture. Seems mouthwatering. Ciao