Norman's blog – archive

All posts.

2024 May 12

Herbert Ives – relativity, the aether, and theory choiceThe 1938 Ives-Stilwell experiment is one of the experiments regularly listed as corroborations of Special Relativity, and occasionally repeated at higher precision. What is much less often mentioned is that Herbert Ives saw this measurement as a confirmation of a rival theory to Special Relativity, which he labelled the Larmor–Lorentz theory, and which he developed and advocated for, for the rest of his life, specifically as a competitive alternative to Einstein's relativity.

2022 April 20 (modified 2022 April 24)

Energy and powerI was talking to a friend recently – well-informed and technical, though not a physicist or engineer – who asked me if I could clarify the subtle differences between ‘energy’ and ‘power’. ‘Subtle?! You mean you don't know?...’ is what I managed not to say. But why would someone know? The distinction is one that most folk need only a vague understanding of; and those who do have to care – the physicists and engineers – have the fundamentals drilled into them so early in their education, that they forget ever not knowing.

2021 September 2 (modified 2021 September 14)

Approaches to accessible mathematical textThe following are notes on various approaches to the problem of producing mathematical text online, in a way which is accessible to folk with one or other visual impairment. The motivating use-case is that of getting maths-heavy lecture notes online, and the discussion is addressed to people with at least some familiarity with LaTeX.

2021 May 16

Producing screen-friendly output from LaTeXI want to produce screen-friendly output from LaTeX, with an auxiliary but important goal being that that screen-friendly output be ‘accessible’. This turns out not to be trivial. But I've managed to get a solution that I, at least, am happy with.

2021 May 1

Geometry: space, spacetime, gravity and gravitational wavesClearly, what the world needs is another explanation of where gravity comes from. This one comes at it from a slightly unusual direction – geometry all the way. We cover quite a lot of ground, here, and some bits are rather hand-waving, because you can pick up further details elsewhere: we could potentially have book-length footnotes all the way through this; the point I want to make is that there is a very direct story which can be uncovered.

2019 October 14

Tuesday: the NHS and successSometimes (to be honest, probably quite a lot of the time) the NHS just works. It's important to be as noisy about its successes as we should be noisy about its stumbles.

2019 June 1 (modified 2019 June 9)

A&C and ElsevierBack in 2012, Bob Mann and I pushed ahead with setting up Astronomy and Computing (A&C) as a journal for the astronomical computing community. We ended up getting Elsevier to publish the journal, with a hybrid access model. This overlapped with the ‘Elsevier boycott’. Below is my brief recollection of why we went ahead by this route. It's not intended to persuade anyone else that we were right or wrong (though I don't feel at all bad about it), or change anyone's mind, but instead to record that it wasn't a thoughtless decision.

2019 April 27

SHA-512 != SHA-512Is it possible to turn a crypt(3) SHA-2 password hash into an OpenLDAP one? Slightly surprisingly, the answer is no, this is not feasible.

2015 September 19

Unicode is simpleThere are many many introductions to Unicode. Here is another.

2015 May 27

Xoxa: normalizing and signing XMLNormalising and signing XML is a well-known pain in the neck. You don't have to look far to find expressions of horror and dismay or even the outright rejection of the idea that XML is signable other than as a text string (Peter Gutmann: ‘XML is an inherently unstable and therefore unsignable data format.’).

2015 March 28

Python methods are not functionsWhen I first looked more closely at Python, I was pleasantly surprised that its semantics seemed significantly simpler than it appeared to be at first: everything's a dictionary, and symbol resolution is a matter of walking up through scopes; functions are first-class objects. It's practically a Scheme!

2015 February 19

A registry of BibTeX conventionsThere are a number of informal BibTeX conventions for things like the url field or doi or eprint. They're 'informal' since they're not documented anywhere, but are either obvious, or have some obvious consensus on use. As well, there's at least one fairly common BibTeX entry type – @webpage – which I at least support in the 'urlbst' style.

2011 October 20

From the Salon: Nuclear Power – Numbers MatterI was one of the participants – one of the speakers – in a production at the Traverse in Edinburgh, by Untitled Projects. The Salon Project was immersive theatre, evoking a 19th century parisian salon, but with anachronisms an important part of the point, and with the talks intended to be (mild) ‘provocations’. In that spirit, I was talking about Nuclear Power – Numbers Matter. This is what I said.

2011 August 29

Programming for AstronomersI gave a talk about Virtual Observatories (and other astroinformatics stuff) to the recent STFC Introductory Summer School in Astronomy 2011, in Glasgow. Here are a few extra notes that occurred to me later, spontaneously or as the result of questions from attendees at the school.

2010 November 6 (modified 2011 June 3)

FITS-WCS is an ontologyAt the 2008 ADASS in Québec, I gave a short talk at the FITS BoF, describing FITS-WCS as an ontology. This (finally) is the worked-out version of that talk, and follows a brief presentation at the FITS BoF at the 2010 ADASS in Boston. It's not that this work has taken two years, but... other things got in the way.

2010 December 20

The Benefits of Digital Preservation: an alternative viewWhat are the benefits of research data management? Neil Beagrie, in the KRDS project, described a number of 'dimensions' in which these benefits could be viewed. Viewing these 'dimensions' in a slightly more mathematical light makes them more vivid (I believe), and allows us to draw some extra illuminating conclusions.

2010 May 8

The necessity for electoral reformFirst-past-the-post (FPTP) is so obviously mad that I find it difficult to believe that anyone defending it is doing so in good faith.

2010 March 20

XML parsers, and the myth of reordering contentXML parsers preserve the order of input elements. Obviously.

2007 June 8

Second Life: MOOs second time aroundI spent a little time in Second Life today, as part of the Emerge tour, thanks to Steve Warburton. It was a curious experience in some ways, familiar in others.

2006 January 22

House of Lords as a supreme courtOn the delights of legal language.