Archive for December, 2011

Dec 07 2011

Black Hole Entropy

Published by under Astrophysics

For those of us who are not anywhere close to being experts on black holes, we can still use our imaginations and think about such things when news comes up.  Evidently, two more super massive black holes, said to be billions of times more massive than the sun, have been found [1].

As far as black holes being black, it is because light entering does not escape them.  Within black holes, and for great distances without, not only would extremely intense magnetic fields change the direction of light travel, it may be that black holes are able to absorb a very high percentage of all incoming electromagnetic energy, utilizing it to maintain and increase structure.  We know from Griffiths and others that “magnetic forces do no work” [2], therefore the energy required to do the work to maintain all aspects of a black hole must come from internal currents and absorbed energy from outside.

If permitted, we can imagine a black hole as a lattice made up of neutron stars.  This does not mean that all neutron stars are the same size, or that all black hole lattices are built the same way.  Each black hole ‘crystal’ structure may be unique.  Spectral distribution of available incoming electromagnetic energy and the sum total of this energy over a period of time are two factors that may come into play.  Most of the electromagnetic energy coming into a black hole at the center of a galaxy cannot escape out the other side, which would contribute to the accelerated expansion of the galaxy.  Entropy may be decreasing for a time within a black hole, seemingly violating the Second Law of Thermodynamics, though the entropy of the entire galaxy, including the black hole, would be increasing.

It may be that as a black hole is concerned, there is very little gravity acting on objects outside the black hole, or none at all.



[2] Griffiths, David J., Introduction to Electrodynamics, Third Edition, Prentice-Hall, Inc., 1999, pg 236

No responses yet

Dec 02 2011

Gamma Ray Burst of Christmas Day 2010

Published by under Astrophysics

As a comet approaches a neutron star, areas of an intensely strong magnetic field can dissolve parts of the comet.  A comet on a direct path that actually collides with the neutron star may penetrate into the neutron lattice, first as a tidal disruption, and then passing through the neutron star and smashing much of it into pieces of a neutron star, along with free neutrons, as it goes.  Each free neutron would decay into a proton, an electron, and an antineutrino, around 15 minutes after gaining its freedom.  In the case of the sustained gamma ray burst which reached earth on December 25, 2010 from the direction of the Andromeda constellation, before which “a comet or asteroid crashed into a neutron star” [1], antineutrinos would have been among the electromagnetic waves reaching the NASA Swift Burst Alert Telescope [2].  This particular gamma ray burst lasted about one half hour.

Gamma rays emitted as antineutrinos from free neutron decay are often between 15 and 340 keV in energy [3].  The gamma rays that BAT read were in the keV range and have nothing to do with gravity at 313 MeV.  The collision would likely have been due to a coincidence of independent path and time since a neutron star that is made up only of neutrons would have no gravitational pull.





No responses yet