Re: Symmetry

There was a series of exchanges, in which Steve Carlip eventually
conceded that naked singularities had been predicted but only in an "
*exact* spherically symmetric collapse, which is not a prediction about
our real universe".

Then I asked " can we say that, the mathematics of GR allows for them
(naked singularities), but they are considered physically unrealistic
and, in 1969, the Cosmic Censorship Conjecture was grafted onto GR for
the sole purpose of forbidding them"?

To which Steve Carlip replied " ...no, it was not proposed because
people thought that naked singularities were physically unrealistic; it
was proposed because it seemed to be true in a large number of examples
that suggested a deeper pattern".

In response, I quoted Penrose:

" ...(an) observer (of a naked singularity) would not be able to
account, in scientific terms, for whatever physical behaviour is seen.
This is the kind of "unpredictability that one wishes to avoid in a
physical situation. One of the reasons for desiring a cosmic censorship
principle, after all, is the elimination of such physical
uncertainties".

In response Steve Carlip wrote:

This is getting a little silly.

Since Penrose was the one who originated the Cosmic Censorship
Conjecture, I didn't find it "silly" to quote him. I thought that his
words might carry some weight.


We don't know whether the cosmic censorship conjecture is correct. That
is, we don't know whether general relativity has the property of cosmic
censorship. That is, we don't know whether physically reasonable initial
conditions in GR can lead to naked singularities.

Clear?

This was all clear to me on October 24th, when I wrote " There is
nothing in GR, per se, that predicts that "singularities will not be
observed" ... ...Cosmic censorship has to be invoked... "

Barry

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