Black Holes and whacky physics on BBC’s Horizon

The Horizon programme’s Who’s afraid of a big black hole (BBC2 16 Feb. and BBC4 19 Feb. 2012) shows how badly so-called ‘leading physicists’ have departed from solid analytical physics.

This programme was a vehicle for physics-mystics; giving up on making their ideas and speculations consistent with normal physics, they opt for changing to some post-modern physics based on undefined theoretical concepts. “The collapse of physics as we know it claims Prof. Andrew Strominger. Black holes, string ‘theory’ and quantum extremism all get a look in. While speculation has a useful role in science, this popularisation doesn’t just belittle established physics, but turns into reactionary anti-physics, giving credibility to wacky statements antithetical to critical science.

These post-modern physicists try to claim the authority of Einstein, though Albert was in fact hostile to black holes and fundamentally critical of quantum mechanics.

The early part of the programme overplays an image of a river flooding over a waterfall, said to simulate space moving ever faster. Not even light can climb out, it states, but no mention is made of ever-slowing light speed on approach to the boundary ‘waterfall’. The analogy between black holes and waterfalls is most misleading and falls far short of Tegmark’s claim that it “lets us calculate all properties of black holes exactly”.

 Max Tegmark tells us Black Holes have existed in theorists’ minds and notebooks for almost a century, “most notably in the mind and notebook of Albert Einstein”. Yet Einstein denied they exist, and showed this in his 1939 paper – which Tegmark simply slates as ‘incomplete’.

Tegmark is evidently a believer in “gravity equals geometry”, giving no ground to critics of this. So he can ignore the maths of the Einstein equation and resort to elementary topology:

imagine that this piece of jelly is the space, then the presence of matter distorts the space.  All massive objects like stars and planets bend the space and time around them. Any object that passes through that warped space time will move as if being pulled by a force, and this is what we experience as gravity.  Anything very heavy and very small would create such a strong gravitational field that space and time would be bent and twisted to breaking point.”

 See how he slides from warped ‘space’ to warped ‘space-time’, making another questionable if common assumption that time and space dimensions are identical (even interchangeable).

His error is that equating gravity with geometry breaks down in strongly-varying gravity. Solving instead the Einstein equation for inward collapsing matter (as Oppenheimer-Snyder considered in parallel with Einstein in 1939) shows that matter collapses onto a shell (Marshall). This solution has no problem with collapse onto a point – Ramesh Narayan‘s talk about a “monster” singularity in the equation from which anything might emerge (as physics can’t predict) is flamboyant nonsense.

The assertion “gravity is not really pulling me down to the ground, it is space that is pushing me down” is not only counter-intuitive (a physicist’s delight) but also misrepresents Einstein’s equivalence principle, as that says nothing about cause. And Einstein’s formulation has limitations, eg. in strongly-varying gravity as above. 

We are told of the core-collapse supernova that left no visible core, yet the programme didn’t tell us of other instances where a remnant central core star is visible. We hear of orbit tracking of some 30 stars near the centre of our galaxy, with Reinhard Genzel claiming nothing fits this other than a black hole. Yet Genzel’s 1996 limit (http://dx.doi.org/10.1038/383415a0) was 100 times the size of the solar system and over 2 000 times the Schwarzschild radius for a mass of 4-million suns. The Schwarzschild radius (R*) denotes the strong (relativistic) gravity regime, so even a far larger partially-collapsed body would easily meet the bill. Eckert and Genzel’s “most probably occupied by a massive black hole” was a huge leap of faith that the journal Nature would normally exclude.

Subsequent studies in 2008 reduced Genzel’s limit from star tracking to 45AU, about 1000 R*, but he still claimed this to be the best evidence that ‘black holes’ exist. In the second edition of Black Holes in the Universe, Begelman & Rees incredibly claim it to be ‘definitive proof’, based on the density of the central mass (from the star orbits) being too high for a stellar cluster, but they do not consider the idealised dust star collapsed on a shell of order R*. The SgrA* radio source near or at the galactic centre is observed to be 6 R* or less, so still does not show the central object is as compact as R*.

Ramesh Narayan talks of other galaxies, in which ‘black holes’ are 1000x more massive and pedantically draws a Figure showing rough proportionality to the galaxy mass. But he doesn’t ask why should a ‘black hole’ which is disconnected from a galaxy follow any such relation. He then jumps to asserting that stellar mass ‘black holes’ are very numerous in every galaxy, everywhere, without evidence.

Andrew Strominger plays the leading anti-physics role: declaring physics is having a nervous breakdown – the collapse of physics as we know it – and asserting that ‘black holes’ are the next step to understanding the universe. It’s “quite likely”, he says, that quantum mechanics is needed to understand the ‘black hole’ singularity. Narayan at least admits that claims of ‘quantum gravity’ being the solution are simply semantics: “we don’t know, have no clues at all” it’s a “theory beyond understanding”.

We are told that black holes are formed from cores of massive stars “imploding all the way down to a point” and “totally mysterious”. The explanation does show the reasoning is inconclusive:   Doug Leonard believes he spotted a black hole when a massive explosion of a supernova signalled the death of a star. After two years he failed to find the central star (on early images) which had exploded as a supernova and disappeared. 

He fails to mention that in other supernova explosions, a central star often remains detectable, in radio waves if not the visible spectrum – so his belief that in the one case it had vanished into a black hole is unscientific.

Finally, after pontificating about the ‘shadow of the event horizon’ and about cracking the problem of quantum gravity, Shep Doeleman gives the game away:
 “It might seem as if it would be easier if things like black holes just went away, but then, where would the fun be?”

This is not serious but speculative non-science. Horizon does us a disservice with such promotion of extreme and ‘reactionary’ post-modern physics.

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3 Responses to Black Holes and whacky physics on BBC’s Horizon

  1. “ever-slowing light speed on approach to…”

    Where do you get this from? What is your source? Thank you for letting me know.

    This is original Einstein – the external observer sees all motions slowing as the Schwarzschild radius is approached, though to a local observer atomic clocks and speeds are unchanged. We do find (in the Oppenheimer-Snyder collapsar model, corrected) that light rays reach through to the interior (whereas mass-particles do not) but are slowed in the proper (external) frame, increasingly as collapse proceeds (pre-Black Hole).

  2. In Einstein’s Special Theory of Relativity (gravitation not included) the speed of light in principle had the freedom of being variable (“A curvature of rays of light can only take place when the velocity of propagation of light varies with position”).

    By including gravitation in his General Theory of Relativity (introducing gravitation as result of curvature of space-time by the division of mass and energy in it), Einstein established two things: gravitation is always pulling and the speed of light is always constant. The speed of light may seem to be slowing down under the influence of gravitation, but that is not really the case because due to the curvature of space-time light has to follow a curved, longer path.

    In my blog “cosmicsignals” I have introduced other ideas. With regard to gravitation and the speed of light see for instance post 12

    .

  3. For regularity’s sake: “other ideas” are my own ideas.

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