Cosmic Horizons

Now, I love a good comedy (and a few bad ones) as much as the next person, but it's grant writing time, and so I am going to be grumpy here. One thing that gets me hot under the collar is terrible portrayals of science, especially astronomy and astrophysics, in the media. Which brings me to exhibit number 1. The TV comedy, Supernova , starring welsh comedian, Rob Brydon . The story is simple. Brydon plays Dr Paul Hamilton, who moves to work at the fictional Royal Australian Observatory, and the laughs come thick and fast in the usual "fish out of water" situations. Well, they don't really, the series was a flop, and lacks a lot of laughs,  but, amazingly, a second season was made. I don't know how I missed this when it was originally shown in 2005/2006, but its portrayal of astronomy and astronomers is, well, rubbish. I would write pages and pages on this, but let's start with some basic things. The Observatory: You can tell by the image above, th...

I love this video and used to do this very demo when teaching classical mechanics. But here's a question for you - why doesn't the wheel fall over? If you trawl the text books, even the wonderful Feynman Lectures on Physics (a must read for any serious student of physics), the answer given is that the wheel doesn't fall down because of the conservation of angular momentum . Alas, I think this answer is a bit of a cop out, and doesn't answer the question. Why? Let's consider the collision between two cars. We know from Newtonian mechanics that momentum is conserved, so the momentum before the collision is exactly the same as after the collision (let's ignore external forces for now, imagine the collision is on a frictionless sheet of ice). The conservation of momentum is a consequence of Newton's third law, and in the collision all of the forces acting have equal and opposite reaction forces, with the total momentum unchanged. Basically, conside...

I've been interested in chaos since reading Gleick's book back in the 1980s. I was first introduced to fractals when I was a summer student at the Rutherford Labs in the late 1980s; this was when colour printers were rare and expensive and I spent a lot of time convincing the guardian of the printer that printing out large colour fractals for my bedroom wall was essential for my studies of proton-anti-proton scattering. But that's another story. A little while ago, I caught an excellent documentary called "The Secret Life of Chaos" by the equally excellent presenter, Jim Al-Khalili . This linked a lot of topics, including chaos and complex systems , which is when a group of things following simple rules results in complicated (and sometimes difficult to predict) behaviour. One of the key things I learnt was the importance of this man in some of the earliest work in the field. I'm sure a number of you recognise him as Alan Turing . I first came across...

One last post for today, as I have conquered movie making in matlab and handbrake (for small values of conquered) to make a movie of particle motion in my 2-d universe. I have softened the interaction so that it is now 1/r (which seems more sensible as we are one dimension down here). Here's the path (again, with the blue dot being the primary mass). And for your viewing pleasure, here's a movie of the orbit

My kids are interested in making a stop-motion movie, so I grabbed Framebyframe for a whirl, and it seems to work. The boys have made a couple of lego movies, but here's my first attempt; I'm quite proud of it.