Daily Archives: February 7, 2012

Incomplete Subtractions

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Well, it has been well over two months since I popped into the studio I sometimes visit to to a “drop in and draw” session. (I’ve spoken about the value of such practice here before.) Although I’ve been drawing a bit here and there on the bus and subway to keep practicing, and also doing some work on some pages of The Project (actually, some pretty detailed finish work on a few pages I’m quite happy with), I was not sure whether I’d have the right chops to do a good job at the session, and expected that if I went I’d have a frustrating -but of course valuable- evening of knocking off some rust and oiling the wheels again. So I went along yesterday.

Strangely, it felt like it was going to be a good session as I approached, and as I settled down and began to try to capture the 2 minute poses, and then the 5 minute poses, I felt like I was flowing along pretty well. It helped that the model on duty is […] Click to continue reading this post →

Double Equivalence

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Wow. So I’ve been wondering how far behind I might be in my lectures for the General Relativity class. I seemed to spend a bit more time than I remember teaching a recap of how to think about rotations, using it as an operational and mathematical brace upon which to build my review/revisit of Special Relativity. I was definitely convinced that I was a bit behind after two lectures on introducing how to study a little geometry using intrinsic quantities rather than by reference to embedding it inside another geometry (e.g., learning to think about a two-sphere in its own right instead of as the surface of a ball – this prepares you for thinking about a three-sphere, for which the ball would be hard to visualize, or draw), and so forth. All solidly useful material for the students (in this and so many other physics pursuits to come), so I do not regret spending time on it, but I did wonder about where I was in the journey…

Anyway, I got to the statement of the Equivalence Principle yesterday, the foundation of the whole of General Relativity. I was feeling quite pleased that we’re starting on this now, putting to use all the hard work we’ve been doing conceptually so far… and thought I’d do a quick post here on the blog to celebrate that we’ve got there. I thought I’d entitle the post “Equivalence”.

I started typing and then thought I’d see if I’d written anything about it here before. […] Click to continue reading this post →