Jack Bruce

I was sad to hear of Jack Bruce's passing. In Cream he was one of the creators of psychedelic and heavy rock. Every kid that picks up a bass guitar learns the riff for Sunshine of Your Love. Those sounds are all around us now, part of the everyday sonic environment.

After that he was in Tony Williams Lifetime, the band that inspired Miles Davis to explore rock music. Jazz-rock also is all around us now, even for people who don't choose to listen to it: TV show themes, film music, even in bloody elevators and when your phone enquiry gets put on hold. Lifetime was pretty much the first jazz-rock band. Full-stop. So there's Jack Bruce helping to kickstart all of that, too. His place in either of his bands would have made him one of the chief architects of the sound of the modern world. To have been in both makes him something very special indeed. We could make a really strong case that he was "Scotland's greatest musician." And that's without mentioning the very many other records and bands he contributed to, many of these really interesting, experimental (like Carla Bley; Michael Mantler; amazing gigs you can find bits of on YouTube).

Recently I'd been listening a lot to Monkjack, one of his solo records. No band, just him singing, piano, one other musician playing Hammond organ; essence of Jack Bruce. It's beautiful - deeply felt, clever, classy classy music. Here he is, not so long ago, with a lovely performance of Weird of Hermiston.

I'm sorry he's gone, a wee bit earlier than many. Our thoughts have to be with his family and close friends. But what a legacy.

Positronium

Science continues to find that homeopathy doesn't work. I know homeopathy has sincere adherents who don't think about scientific evidence in the same way as the rest of us. I admire those people who are constantly in debate with them and I'm glad my own area of science is a long way away from this sort of topic. So I was quite taken aback to come across this account of positronium homeopathy.

Positronium is a sort of an atom but a very exotic one, with only a fleeting existence. Like an atom of hydrogen it consists of two elementary particles with equal and opposite electric charges. Like an atom of hydrogen one of these particles is an electron, familiar (as far as any subatomic particle is "familiar") as a constituent of the atoms around us. Unlike a hydrogen atom the positively charged particle is a positron. A positron has the same mass as an electron but a positive, rather than a negative charge. It is the electron's antimatter counterpart, a sort of evil twin. When an electron and a positron come together they cancel one another out (the word used is "annihilate") and the mass of both particles is converted into energy, in the form of light, according to Einstein's most famous relation E = mc².

Antimatter sounds like something out of science fiction (and one of its most famous occurrences must certainly be in the propulsion unit of the Starship Enterprise). Nonetheless it exists. The first discovery of a positively charged electron was in 1932 by the American scientist Carl Anderson. Now they are put to work every day in our hospitals (know somebody who's had a PET scan? Guess what the "P" in "PET" stands for).

Natural processes produce positrons, as do events in man-made particle accelerators. My own interest focuses on the energetic events of solar flares, in which positrons are sometimes produced. Once they exist, positrons don't hang around for very long. There's usually an electron for them to annihilate with. But before annihilating, for a ten-millionth of a second or less, the positron and the electron orbit one another as an atom of positronium. I like to think of them in a sort of dance, eyeball to eyeball, each recognising in the other its equal, its opposite and its imminent extinction. Finally they annihilate one another, producing a spectrum line in gamma-rays that we can detect and learn from.

Composed only of two very simple objects, the positronium atom gives very precise tests of the quantum theory of electromagnetism, so it has been studied in great detail in the laboratory. It lets us test very precisely elements of our basic understanding of the world.

Matter and anti-matter can both exist but there is more matter than anti-matter. If there were equal amounts of both, they would have annihilated each other very early in the history of the Universe. The Universe would be filled with light but there wouldn't be atoms and molecules i.e. ourselves. So the question, "why is there more matter than anti-matter" is a fundamental question about the Universe.

After all this I'm both sad and a bit cross to discover talk of "positronium homeopathy". In its yin-and-yang components, its brief existence, its annihilation, and the matter-antimatter asymmetry at which it hints, positronium is a very beautiful and exotic aspect of the physical world. There's more than enough real, deep beauty and weirdness there without making up a lazy, unsubstantiated fairy story.

An evil tree

Probably it is not evil. In Pollok Park it must see so many passers-by that any routine evil-doing would have become well-known. Of course it might choose shrewdly its victims and the moments to take them. A park in a big city will supply them fairly regularly: alone and melancholy, remote from or devoid of friends and family. Nobody will notice if they never return from some restless nocturnal stravaig. The end of unrest might even be a kindness.

Probably it is not evil. Nothing happened to me. I was able to photograph it. But I was there in daylight; other people were around; I am not unloved.

Probably it is not evil. It is not after all an ill-favoured Ash Tree. Still, Let's hope they chop the thing down. Yes, Let's hope they chop the thing down.