Is dark matter locked up in primordial black holes?


Dark matter pie
Dark matter pie (Photo credit: Wikipedia)

To be honest, I have an issue with both “dark matter” and “dark energy” – they both look like close-to-metaphysical constructs to me: we have a hole where theory and observation do not match so we’ll invent this latter-day phlogiston and call it “dark”.

Then again, I’m not really qualified to comment and it is pretty clear that observations point to missing mass and energy.

I have another issue – if most of the mass of the universe is in the “dark matter” why is there no obvious evidence of it nearby? I don’t mean why can’t we see it – as obviously that is the point – but even though we sit in an area (Earth) of local gravitational field maximum we are struggling to see any local mass effects. (For instance this paper talks about how “local” conditions should impact any dark matter wind but, as far as I can see at least, it’s all entirely theoretical: we haven’t seen any dark matter wind at all.)

So the suggestion – reported in the New Scientist – and outlined in this paper – that actually dark matter is locked up in black holes caused by sound wave compression in the earliest moments of the universe has an appeal. It also potentially fits with the observational evidence that dark matter appears to be knocking around in the halos of galaxies.

These primordial black holes are not a new concept – Bernard Carr and Stephen Hawking wrote about them in 1974 (in this paper). The new evidence for their potential as stores of dark matter comes from the already famous Laser Interferometer Gravitational-Wave Observatory (LIGO) experiment – as that leaves open the prospect that the two black holes that generated the detected gravitational waves could both be in a galactic halo and of the right mass spectrum to suggest they and similar bodies accounted for the gravitational pull we see from dark matter.

All this is quite speculative – the paper points the way to a new generation of experiments rather than proclaims an epoch making discovery, but it’s obviously very interesting and also suggests that the long search for WIMPS – the hypothesised weakly interacting particles that have previously been the favourites as an explanation for dark matter – has essentially been in vain.

Review of “The Black Cloud”


Cover of "The Black Cloud"

My interest in astronomy and astrophysics comes from childhood and when I was much, much younger I had an (unscientific) fondness for the “steady state” theory of cosmology, which, in the early 1970s was not as thoroughly discredited as it is today (though, of course, many newer cosmologies borrow from it or show similarities to it – for instance Roger Penrose‘s proposal in Cycles of Time).

Part of the attraction of the steady state cosmology was the figure of Fred Hoyle, or at least how I imagined him: blunt speaking, no nonsense, scientific genius. But until I read The Black Cloud I had not read any of his scientific or literary works.

The book is fascinating as a period piece and not a bad read as a piece of science fiction either – though the overall tone and dialogue reminds me of “Journey into Space” – a 1950s BBC science fiction radio serial recently re-broadcast.

But here is a novel with differential equations, computer program listings (presumably in machine code of some sort as it certainly is not a high level language) and a description of the (then) pioneering technology of pulse code modulation.Not all the science is good though, but Hoyle cannot be blamed for that: although it does not use the term, the view of artificial intelligence here is the conventional one of the time, but also one that fifty years of rapidly advancing computing power has failed, thus far at least, to sustain.

Mixed, with that, though is a fair dose of of Little Englandism, enormous doses of sexism and a quite frightening view into how Hoyle thinks society should be organised – namely with politicians, the people we chose, removed and the dictatorship of the scientists instituted. Stalin ruled in the name of science too.

Hoyle’s preface implies it would be a mistake to ascribe the views of Chris Kingsley, the chief advocate of crushing politics, to himself, but the character sounds far too much like him – the man who once exploded with anger when a snotty PhD student called Stephen Hawking pointed out a flaw in his calculations because he thought it would weaken his attempted blackmail of politicians – for the denial to be credible.

It’s a great book and an easy read, so I do recommend it.

Do universities fail science students?


President Barack Obama talks with Stephen Hawk...
Image via Wikipedia

There is a very interesting article on the THES website today – “So last century” – which says that universities are failing students because they teach them in such a compartmentalised way.

Whether the study is conducted by the CBI in the UK or by commercial for-profit educational providers drumming up business for their remedial post-baccalaureate job-training services, everyone seems to acknowledge that today’s students are good test-takers but lack the workplace essentials necessary for the 21st century. These include people skills (especially in diverse global contexts), communication skills, collaborative skills, analytical skills, networking skills, an ability to synthesise information across a wide range of evidence, and even the most elementary skills, such as how to write a great job application letter and curriculum vitae or represent their character and talent at a job interview. No wonder they face the career centre with such trepidation.

Well, while the article is well written and an interesting read I think it is fundamentally wrong.

My objection is not just the standard, liberal, view that actually universities are not meant to be factories turning out people fit for labour (albeit higher labour) – though it is partly that. Good employers invest in their employees in any case and do not expect them to be delivered for free as the fully formed article.

I certainly do not believe that there was some golden age where graduates were being turned out with all these skills either. One only has to look at the somewhat doolally behaviour – from Newton onwards – of some of the greatest scientists to know that academic excellence and socialisation are always the easiest of bedfellows.

But it is more fundamental – degrees have to be specialised, certainly in science, because they also have to be, at least partially, grounded in research and a preparation for research.

My first degree was in Astrophysics. “Communication skills, collaborative skills…” and all the rest of it have nothing very much to do with cosmology and every minute that would be spent teaching me about them would be a minute wasted in preparing me for being an astrophysist.

The fact I never became an astrophysist is hardly the point – there would not have been much point to an astrophysics degree if it at least did not offer that path.

Science degrees need to be specialised because science is ever-more complex and specialised. Some scientists think this may be a temporary thing – in A Brief History Of Time Stephen Hawking suggests that further scientific advance might simplify our theories – but there is no sign of that at present.

So, if universities are to produce scientists they have to focus on science and not think of themselves as pre-office work trainers.