Archive for April 5, 2017

Going NUTs

Posted in The Universe and Stuff, Uncategorized with tags , , , on April 5, 2017 by telescoper

If you’ve studied General Relativity the chances are that you’ve come across the Taub-NUT exact solution discussed in this post. It’s generally regarded as something of an oddity in that it’s a bit contrived, but provides a counter-example to some well-known results. For example, in the context of a Black Hole solution, it violates the No Hair Theorem (by violating the assumption of asymptotic flatness).

When I saw this post at CQG, however, I was reminded of a paper published a few years ago discussing this in a cosmological context, where it can be seen as a special case of the Bianchi IX geometry.

CQG+

By Paul I. Jefremov and Volker Perlick.


Among all known solutions to Einstein’s vacuum field equation the (Taub-)NUT metric is a particularly intriguing one. It is that metric that owing to its counter-intuitive features was once called by Charles Misner “a counter-example to almost anything”. In what follows we give a brief introduction to the NUT black holes, discuss what makes them interesting for a researcher and speculate on how they could be detected should they exist in nature.

paul jefremov-and-volker Volker Perlick and Pavel (Paul) Ionovič Jefremov from the Gravitational Theory group at the University of Bremen in Germany. Volker is a Privatdozent and his research interests are in classical relativity, (standard and non-standard) electrodynamics and Finsler geometry. He is an amateur astronomer and plays the piano with great enthusiasm and poor skills. Paul got his diploma in Physics at the National Research Nuclear University MEPhI in Moscow, 2014. Now he…

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The Word, by R.S. Thomas

Posted in Poetry with tags , , , on April 5, 2017 by telescoper

A pen appeared, and the god said:
‘Write what it is to be
man.’ And my hand hovered
long over the bare page.

until there, like footprints
of the lost traveller, letters
took shape on the page’s
blankness, and I spelled out
the word ‘lonely’.

And my hand moved
to erase it; but the voices
of all those waiting at life’s
window cried out loud: ‘It is true.’

by R.S. Thomas (1913-2000)