Friday, September 23, 2016

Q&A - 23/9

Gleick, Genius

When [famous physicist] Bethe and Feynman went up against each other in games of calculating, they competed with special pleasure. [..] Early in the project they were working together on a formula that required the square of 48. Feynman reached across his desk for the [..] calculator. Bethe said, “It’s twenty-three hundred.” Feynman started to punch the keys anyway. “You want to know exactly?” Bethe said. “It’s twenty-three hundred and four. Don’t you know how to take squares of numbers near fifty?” He explained the trick. Fifty squared is 2,500 (no thinking needed). For numbers a few more or less than 50, the approximate square is that many hundreds more or less than 2,500. Because 48 is 2 less than 50, 48 squared is 200 less than 2,500—thus 2,300. To make a final tiny correction to the precise answer, just take that difference again—2—and square it. Thus 2,304.


On TV-land and movies a smart person, scientist is portrayed as a fast, mental calculator, one on a scifi show "knew" Pi to the 50th digit for example.  But the former usually comes across as "raw computation, as if there is computer in one's head", and the latter as pure memorization.

Mathematics driven smarts has nothing to do with any of that. In the excerpt above Bethe actually used simple high-school algebra (Gleick did not include that part, or he missed it himself). It is simple quadratic equation, (x-y)^2 = x^2 - 2xy + y^2. Take x=50, and y=2, you end up (50-2)^2 meaning 48^2. That is the goal, but representing it through that simple equation, Bethe ends up with simple multiplications and additions on the right handside, such as 50^2, -4*50, or +4.  That part anyone can do in their head.

Like I said before, mathematics makes things easier. That is why scientists use it.

Scientist S. Michalakis

I help Hollywood film-makers get their science right

Who is going to help you to get your science right?

Frickin Malakifuckinananlis.. Dude told Ant-Man makers once things get really small and you’re down to the quantum realm, you don’t have space or time".  TV land also loves "the many-worlds interpretation", "there are infinite number of universes anything possible is happening there"... Someone has to make it clear to these show writers that a lot of this stuff is unsubstantiated bullshit. They are unproven theories. You can make the mathematics say anything, but will it say anything concise, and that can be proven? How many dimensions does the universe have? String Theorists are like 8,9! 15! Dude.

MWI is especially attractive to script writers: they get to use the same actors, little in-show recycling, they give one a goatee, and maybe a leather pant with a butt cut-out, so they are "bad" in this other universe, and they do all these crazy things. It's fine for the actors, they get to practice their "range". Fine. But viewers beware. 

[Lunch with physcist Carlo Rovelli] A theory called “loop quantum gravity” that Rovelli has done vital work to develop with his colleague Lee Smolin, who he describes as “my best friend and collaborator”, addresses that contradiction [between relativity and quantum mechanics]. If proven, it would represent one of the holy grails of physics.  “The theory is more or less there, it is written,” he says. “There are things we don’t understand yet, but the question is how you test it.” If it can be found to work, then Rovelli’s peers who have spent their careers working on a rival approach, string theory — about which Rovelli is respectfully dismissive — would find all their toil and sacrifice come to nothing. “It’s like playing football,” he shrugs, “either you win or you lose.”


I like this guy; he is dismissive of String Theory (Stephen Hawking loves it by the way), and is respectful of Einstein's work. I smell a quality theory here (I read Rovelli's book too, good stuff).