A Conversation for Black Holes

BBC Horizon documentary

Post 1

BigAl Patron Saint of Left Handers Keeper of the Glowing Pickle and Monobrows

Just been watching this, I think it was called 'Who's Afraid of a Big Black Hole'.

The scientists being interviewed universally said words to the effect that black holes are the strangest/weirdest things in the whole Universe, and that they didn't understand them.

As you say, black holes are at the centre of every galaxy in the Universe ('super-massive BH's'), , and others exist outside of galaxies so, in fact, they are extremely common. Their presence dictates the evolution and shape of galaxies. Interestingly, according to Horizon, there is a straight line correlation between the size of black holes and the size of galaxies, with the mass of the galaxy being 10 x the mass of the Black Hole.

Furthermore, one smiley - scientist claims to have photographed a BH (or rather the position where a BH is known to be. This came about because a supernovas was observed. Wishing to test their understanding of how supernovae occur, the smiley - scientists trawled back through images taken by the Hubble Space Telescope amd eventually found one taken some years earlier which showed an extremely bright star at the position which was now a supernova. The bright star was, in fact, far brighter than the galaxy it was in! The smiley - scientists continued to observe and photograph the star for a further two years - after which there was nothing to be observed - which you'd expect, it was a BH smiley - biggrin.

However smiley - scientists believe that it should be possible to observe and photograph a halo of light at the point where photons, attracted from everywhere by the mass of the BH, disappear into the BH at the position of the 'event horizon'.

By studying BHs, smiley - scientists hope eventually to unify Einstein's Theory of Relativity (which works for things on the astronomical scale) with Quantum Mechanics (which works on the sub-atomic scale). At the moment equations based on GR, which work perfectly outside of the event horizon, give answers of 'infinity (totally unsatisfactory, meaningless) for events inside the event horizon.

This Entry is ripe for an Update methinks smiley - biggrin

BBC Horizon documentary

Post 2


You are right that this needs an update. I have watched that documentary and have read about general relativity (I made a guide entry on General Relativity), I have to say that the scientific content of the entry was slightly limited. Other than that I would rate it 4/5. smiley - ok

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