Exam Heat
We had a midterm in the undergraduate General Relativity class this week. Midterm II. We’d just come off a batch of lectures on black holes (focussing on Schwarzschild and Kerr), and so it seemed very natural to focus on that as the topic. Schwarzschild is the most basic (vanilla) black hole and Kerr is the case of having rotation for a bit of extra flavour. They are both hugely important in real physics – the former for the basic phenomena and then the latter since most objects out there in the astrophysical realm are actually going to be rotating to some degree (and after gravitational collapse, probably a high degree). So I focussed on those in class.
For the midterm therefore, I got the opportunity to have them discover properties of the (less astrophysically important perhaps) charged black hole – the Reissner-Nordstrøm solution:
[tex] ds^2=-\left(1-\frac{2M}{r}+\frac{Q^2}{r^2}\right)dt^2+\left(1-\frac{2M}{r}+\frac{Q^2}{r^2}\right)^{-1}dr^2+r^2\left(d\theta^2+\sin^2\theta d\phi^2\right)\ ,[/tex]
…and do a few computations with it analogous to what they did for the other cases in class and in homework. I hope they had fun (like discovering that for a […] Click to continue reading this post

By the way, for those of you in the area, don’t forget that the LA Times 

I’ve been coorganizing an event as part of their series of lectures that accompanies the event and I am delighted to announce that I have connected two of the most awesome spaces and institutions in the city for this one. The Griffith Observatory will team up with the Natural History Museum for this one, with a lecture and Q+A session, and then (weather permitting) a bit of stargazing in the new gardens! Please spread the word and come along: […] 






