All the above featured on the open day poster covering nuclear physics research in the Department. For those not around when Crosby, Stills, Nash and Young’s album Deja Vu came out in 1970, the connection is the lines in the album’s song Woodstock ‘We are stardust, we are golden/We are billion year old carbon’. This is true, although I guess most of the carbon in our bodies is billions of year old not just a billion years old. But that is close enough, and we are certainly stardust, the carbon in our bodies was made in stars.
Anyway, music references and nuclear physics are par for the course with my colleague Wilton Catford. It left me feeling a bit sad that the soft-matter (my group) posters were a bit lacking. They completely lacked music references. And no stardust – I was going to say literally no stardust but of course the posters are made of stardust too.
But to be honest I cheered up when I realised that the third group, who work on lasers etc, missed an open goal. Despite lasers featuring in many song lyrics, even in the odd title such as the (rather more recent than Woodstock) Laserlight, their posters also lacked musical references. Clearly, we both need to learn from Wilton.
The posters were for an open day. I think it went well, we had maybe 140 prospective students and their parents visit us, and I think they left with a good impression of us.
My favourite question of the day was asked by one of the prospective students. It was “How can maths find anything new about the universe?”. I think that’s a very good question, and as a theoretical physicist, I guess I should be able to answer it or I should resign my position. One of the things I love are simple, almost trivial looking questions, that are really interesting and important.
In answer, I talked about maybe the classic example of maths discovering something real. This is Paul Dirac‘s prediction of a new particle: the positron. The positron is the anti-matter equivalent of an electron. In brief Dirac was combining early quantum mechanics with relativity in the 1920s, and found equations that could predict properties of the electron – which was then already known. That was good.
But his equations had another solution, another particle. The positron. Dirac found it in his equations. The positron was then seen in experiments just a few years later. The image up top is of one the tracks from the origina 1933 paper by Carl Anderson announcing his detection of the positron. He won the 1936 Nobel prize in physics for this. In the image the positron is the faint line that goes from bottom to top and curves to the left. The horizontal bar is a sheet of lead the positron goes straight through.
