A Portal Special Presentation- Geometric Unity: A First Look: Difference between revisions

Line 234: Line 234:
<p>[00:41:47] What is physics to physicists today? How do they see it different from the way in which we might imagine the lay person sees physics? [[Ed Witten]] was asked this question in a talk he gave on physics and geometry many years ago, and he pointed us to three fundamental insights, which were his big three insights in physics.
<p>[00:41:47] What is physics to physicists today? How do they see it different from the way in which we might imagine the lay person sees physics? [[Ed Witten]] was asked this question in a talk he gave on physics and geometry many years ago, and he pointed us to three fundamental insights, which were his big three insights in physics.


<p>[00:42:13] And they correspond to the three great equations. So the first one is, is that somehow physics takes place in an arena and that arena is a [[manifold]] X together with some kind of [[semi-Riemannian]] [[metric structure]], something that allows us to take length and angle. So that we can perform measurements at every point in this space-time or higher-dimensional structure, leaving us a little bit of head room. The equation most associated with this is the [[Einstein field equation]].
<p>[00:42:13] And they correspond to the three great equations. So the first one is, is that somehow physics takes place in an arena and that arena is a [[manifold]] $$X$$ together with some kind of [[semi-Riemannian]] [[metric structure]], something that allows us to take length and angle. So that we can perform measurements at every point in this space-time or higher-dimensional structure, leaving us a little bit of head room. The equation most associated with this is the [[Einstein field equation]].


<p>[00:43:12] And, of course, I'm running into the margin. Okay.
<p>[00:43:12] And, of course, I'm running into the margin. Okay.