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### Andrew Chamblin Memorial Lecture

This is primarily a thank-you to the organisers of the annual Andrew Chamblin Memorial Lecture in Cambridge. I attended yesterday courtesy of the Department of Applied Mathematics and Theoretical Physics, and it was fascinating to hear Kip Thorne, until recently Feynman Professor of Physics at Cal Tech, give an insider view on the development of gravity wave astronomy and the LIGO observatory.

The lecture was packed - in fact, it appeared to be relayed into other lecture theatres by video link - with an audience that would have given a brilliant score in the I-Spy Book of Physicists (had such a book existed). Thorne began by asking how many in the audience had physics degrees, doctorates and beyond - it was a distinct majority in the main room, but he then made it clear he was addressing his talk primarily to the non-technical remainder, and managed to do so very effectively.

What was particularly interesting from my viewpoint was the speaker's ability to balance the scientific content with the political, organisational and personal aspects of getting a project of this size off the ground. I won't relay lots of detail here, but one very effective story brought out the scale of the problem facing those building the LIGO detector. Thorne pointed out that in a book on gravitation he had said that a LIGO-style detector was 'not promising'. This was because of the scale of the movement of a mirror that has to be detected to 'see' a gravitational wave. Thorne built this up impressively:

If you begin with 1 centimetre and divide by:
• 100 you get the thickness of a human hair (10-4 m). Divide by
• 100 again you get the wavelength of the light being used to make these measurements (10-6 m).  Divide by
• 10,000 you get the diameter of an atom (10-10 m). Divide by
• 100,000 you get the diameter of the nucleus of an atom (10-15 m). Divide by
• 100 again you get the magnitude of the largest motion (10-17 m) we might expect to see in the separation between the mirrors a few kilometres apart.
It was a surprisingly exhausting day, making a 9 hour round trip for just over an hour's lecture - but well worth it.

And that round trip did include a walk back to the station across one of the more remarkable parts of (pretty much) central Cambridge, pictured here - a relaxing end to the day.

### Why I hate opera

If I'm honest, the title of this post is an exaggeration to make a point. I don't really hate opera. There are a couple of operas - notably Monteverdi's Incoranazione di Poppea and Purcell's Dido & Aeneas - that I quite like. But what I do find truly sickening is the reverence with which opera is treated, as if it were some particularly great art form. Nowhere was this more obvious than in ITV's recent gut-wrenchingly awful series Pop Star to Opera Star , where the likes of Alan Tichmarsh treated the real opera singers as if they were fragile pieces on Antiques Roadshow, and the music as if it were a gift of the gods. In my opinion - and I know not everyone agrees - opera is: Mediocre music Melodramatic plots Amateurishly hammy acting A forced and unpleasant singing style Ridiculously over-supported by public funds I won't even bother to go into any detail on the plots and the acting - this is just self-evident. But the other aspects need some ex

### Is 5x3 the same as 3x5?

The Internet has gone mildly bonkers over a child in America who was marked down in a test because when asked to work out 5x3 by repeated addition he/she used 5+5+5 instead of 3+3+3+3+3. Those who support the teacher say that 5x3 means 'five lots of 3' where the complainants say that 'times' is commutative (reversible) so the distinction is meaningless as 5x3 and 3x5 are indistinguishable. It's certainly true that not all mathematical operations are commutative. I think we are all comfortable that 5-3 is not the same as 3-5.  However. This not true of multiplication (of numbers). And so if there is to be any distinction, it has to be in the use of English to interpret the 'x' sign. Unfortunately, even here there is no logical way of coming up with a definitive answer. I suspect most primary school teachers would expands 'times' as 'lots of' as mentioned above. So we get 5 x 3 as '5 lots of 3'. Unfortunately that only wor

### Which idiot came up with percentage-based gradient signs

Rant warning: the contents of this post could sound like something produced by UKIP. I wish to make it clear that I do not in any way support or endorse that political party. In fact it gives me the creeps. Once upon a time, the signs for a steep hill on British roads displayed the gradient in a simple, easy-to-understand form. If the hill went up, say, one yard for every three yards forward it said '1 in 3'. Then some bureaucrat came along and decided that it would be a good idea to state the slope as a percentage. So now the sign for (say) a 1 in 10 slope says 10% (I think). That 'I think' is because the percentage-based slope is so unnatural. There are two ways we conventionally measure slopes. Either on X/Y coordiates (as in 1 in 4) or using degrees - say at a 15° angle. We don't measure them in percentages. It's easy to visualize a 1 in 3 slope, or a 30 degree angle. Much less obvious what a 33.333 recurring percent slope is. And what's a 100% slope