Re: CMBR and neutron stars

David A. Smith wrote:

> ... we don't discover entirely new galaxies where none
> existed before, say, 10 or 20 years ago. We are only
> able to bring new more-distant ones into focus.

Twenty years ago we couldn't even see new stars forming
in our own galaxy. Only the introduction of infrared
telescopes in Space made it possible.

Perhaps someday we will gain access to astronomical
records going back hundreds of millions of years, and
they will show that we can see galaxies now that did
not yet exist at that earlier time.

On another aspect of this topic: I *sort of* agree that
a black hole's event horizon is a singularity. It is
the limit beyond which light cannot reach distant parts
of the Universe. As a "limit", it is a "boundary", and
thus a sort of singularity. But an observer close to
the event horizon-- on either side, or exactly on it--
would see nothing special there.

When I have seen the term "singularity" in reference to
black holes, it has *always* (before this thread) been
referring to the thing at the black hole's center, never
the event horizon or anything else. Black Holes & Time
Warps: Einstein's Outrageous Legacy (1994, Kip S. Thorne)
has a glossary in the back. The entry for 'singularity:

A region of spacetime where spacetime curvature becomes
so strong that the general relativistic laws break down
and the laws of quantum gravity take over. If one tries
to describe a singularity using general relativity
alone, one finds (incorrectly) that tidal gravity and
spacetime curvature are infinitely strong there.
Quantum gravity probably replaces these infinities by
quantum foam.

Whatever that means. :-)

-- Jeff, in Minneapolis

.

Relevant Pages

  • Re: CMBR and neutron stars
    ... > David A. Smith wrote: ... > they will show that we can see galaxies now that did ... > a black hole's event horizon is a singularity. ... Black Holes & Time ...
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  • Re: error in mathematics behind black holes
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  • Re: GAMMA RAY BURSTS (GRBs) explained by new paradigm black hole splitting.
    ... collision of two unequal sized black holes. ... The new God (Higgs) particle and the second Law. ... The Higgs system comprises real shaped Higgs particles which are ... a SINGULARITY is a globular point in the Higgs system where the ...
    (sci.physics)
  • Re: error in mathematics behind black holes
    ... lecture notes on black holes ... I also read the articles by Stephen Crothers about the black hole ... singularity. ... be expressed in whatever coordinate system you want. ...
    (sci.physics.relativity)
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