Tuesday, June 21, 2016

Short items

Here are a few items:

  • This is fantastic.  Eric Schlaepfer, a hardware engineer at Google, has built a "disintegrated circuit", making a 6502 processor (the CPU from the Apple II and also used in one of my favorite undergrad courses back when I took it) out of surface-mount transistors.  It can't run at MHz clock speeds because of the stray capacitance of the traces on the circuit board, but it's still amazing.  If you want a metric for modern processors, if you made a version of the processor for the iPad Air 2, it would cover 82000 m2.
  • This is a bit "meta", but here is Peter Woit's recent Quick Items link.  I've steered clear from the whole multiverse discussion, but wow, I find it very disturbing how much recent mass publicity has been given to an idea that is described, at best, as an extremely speculative notion.  It's like having Bayesian arguments about how many angels can dance on the head of a pin.
  • Speaking of absurdist speculative garbage, Michio Kaku in recent days has claimed that we will shortly be able to create avatars that will live after us based on uploaded memories, and that we are living in The Matrix, which proves the existence of God.   How has this person become one of the well-known faces of science popularization?
  • American Ninja Warrior really is a good way to illustrate some fun physics.
  • Geekwrapped has highlighted this blog as one of the 20 best science blogs out there.  Thanks!


Anonymous said...

Hello professor Natelson,

I'm the anonymous poster on the LGBT stuff. Well, this comment is not that. My questions for you is about bullet trains & supercoductors, which is a condensed matter topic, maybe. Whenever I read something about superconductors, it's always about how it is used in levitation for speed trains. I don't get it. Why should trains go fast? You hear on the news of train accidents because of speed. And isn't that not cost effective? There's friction (air and otherwise) involved. And how do you keep things below liquid Nitrogen temperature for rails that go miles and miles? Please explain the physics to me about this, either as comment to this comment, or a post itself. If you already posted about this, then sorry. But thank you for reading this.

Douglas Natelson said...

Hi Anon. There is clear demand in many places for high speed rail, to compete with air travel. It's very successful in Japan, Europe, and recently China, though of course there are safety concerns as with any mass transit system that involves hundreds of people in a thin-walled metal tube traveling hundreds of km/h. A major issue in high speed rail travel is track maintenance and quality, since defects there could lead directly to derailments. Similarly, proper maintenance of the train carriage wheels is expensive and demanding, since it involves many moving parts. If you could get nearly frictionless (as far as interactions with the track are concerned) motion with no moving parts, that could be really appealing. Magnetic levitation is one way you could imagine doing this. You can do this inductively without superconductors (see here for an old example, though I really don't like the verbal description), but it's very energetically wasteful. Unsurprisingly, people would really like room temperature superconductors with suitably large critical fields and currents, etc. to make the Meissner Effect version of this possible without LN2 cooling.

gilroy0 said...

Congrats on the Geekwrapped thing.
Kaku is the face of science popularization because he says outrageous things with charm and wit. People -like- the craziness; it's like the sugar coating in cereals. Nobody eats Frosted Mini Wheats for the wheat.

DanM said...

I'm amused by Sean Carroll's advocacy of his recent book, which includes the admonishment "you can't derive 'ought' from 'is'", as a tag line to remind us that morality is subjective. But of course he is also a firm advocate of the multiverse description, which is as good an example of deriving 'ought' from 'is' as any that I can imagine. He thinks it 'ought' to be the case, therefore he claims that it 'is'. Despite the stunning lack of evidence. Head of a pin, indeed.

Alessio Gagliardi said...

Dear Douglas
I always read your blog with great interest.

By the way: nice book :), just bought at StatPhys in Lyon.