Sunday, March 25, 2018

Antimatter Production at a Potential Boundary


Recorded: 6/17/2017 Released: 3/25/2017

Randy discusses a proposal for the production of antimatter without using supercolliders with Jim. This proposal would have used Klein's paradox for the production of electron-positron pairs at a very sharp, steep potential boundary produced through the Casimir effect.

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Notes:

1. The paper we read for this program:


2. The NASA Institute for Advanced Concepts no longer exists (apparently it closed down in 2007), but there is now a NASA Innovative Advanced Concepts, a program with the same acronym that seems to have a similar purpose (if not, tell me the salient difference in the comments).

3. Our listenership has increased markedly since we recorded this episode last June. We had 1,057 downloads in the first fifteen days of June 2017, and in the first two weeks of March we had 3,117. In both cases there were no podcasts published during the time interval (in the current case because this is my heavy semester at work and it eats into my free time).

4. Our subreddit.

Friday, March 16, 2018

The Nature of Space and Time by Hawking and Penrose

Stephen Hawking died two days ago, and I have a copy of The Nature of Space and Time sitting in my review pile waiting its turn. It doesn't have to wait its turn, though, because (1) Stephen Hawking died (did you hear?) and (2) It's short and so easy to review.

The premise of the book is that it is a series of lectures by Hawking and his mentor Roger Penrose. This was "the high point of a six month program held in 1994 at the Isaac Newton Institute for Mathematical Sciences at the University of Cambridge." I'm not sure where Cambridge is or what it's famous for, but I'm sure this was the hottest thing going in that half-year. The book itself is not a debate, only the last of the seven chapters. The first six are lectures alternately by Hawking and Penrose building up to the debate. If the seventh lecture was the high point of the program, the lectures certainly built up the dramatic tension in exactly the way universities don't build up dramatic tension.

The lectures are semi-non-technical. By that I mean that Hawking and Penrose can't help themselves and they put the pretty equations in the text for you to admire, but they aren't used for anything. So, really, they're nothing more than window dressing for the topic at hand. The topics are the classical theory of space and time (what is the future, what is the past, do they always exist?), singularities in space time (and some ideas about them), many varieties of quantum mechanical stuff (quantum black holes, quantum cosmology, quantum gravity), and twistor theory. Not necessarily light subjects, but presented in a way that most anyone should be able to understand.

And here both Hawking and Penrose get a chance to discuss some of their theories, like: why, exactly, would nature abhor a singularity? How exactly does it go about hiding them?

To be honest, the debate doesn't seem to be very heated when you get to it. It's just a restatement of the positions outlined beforehand, mostly. Not much "here's why I'm right and you're wrong." So, if you were waiting to find out who won the debate, I'm sorry: it wasn't that kind of debate.

What I'm thinking about reading: