Behold the Amplituhedron

Have you read about this amplituhedron thing? Here’s an article that describes it: Physicists Discover Geometry Underlying Particle Physics.

You’ll be happy to know that the related improvements to twistor theory vastly simplifty the Britto–Cachazo–Feng–Witten recursion involved in the scattering process. In fact, I suspect you’ll never look at Britto–Cachazo–Feng–Witten recursion the same way again.

What I like about this is that it sounds so much like the crackpot science of mumbling weirdos. Or even better, the whole article reads like the loopy faux-physics back story in science fiction movies. You know, when the geeky scientist guy explains to the protagonist why the time machine works or the faster than light toaster or whatever.


I mean, this is from the first line of the article: We have “discovered a jewel-like geometric object that dramatically simplifies calculations of particle interactions and challenges the notion that space and time are fundamental components of reality.”

A coruscating jewel at the heart of space-time. Thousands of hours of supercomputer time reduced to a scrap of paper. The foundations of physics buckling and reshaping before our eyes.

Yeah right. Sounds like H.P. Lovecraft to me.

You read this, and you think, oh wait, these people are credible? Institute for Advanced Studies, Harvard, Oxford?

Sometimes a little math does the trick. Sometimes truth is as good as fiction. In 1931, while Einstein and his wife were visiting Caltech, they took a trip to the Mount Wilson Observatory. As Einstein admired the gigantic device, his wife Elsa got the last word.

Like a child at play, [Einstein] scrambled about the framework, to the consternation of his hosts. Nearby was Einstein’s wife, Elsa. Told that the giant reflector was used to determine the universe’s shape, she reportedly replied, “Well, my husband does that on the back of an old envelope.”

(from National Geographic)

A Sunset Clock

About this time every year I start to get obsessed with the sunset. Since we’re close to the equinox, the sunlight is disappearing at the fastest rate we’ll see all year. This fact alone separates me from the people who talk about autumn as their favorite season. Beautiful colors, apples and pumpkins, crisp temperatures, and clear blue skies. Sure. I won’t say those things aren’t nice. But the darkness creeps in like a mist. It smiles an oily smile as it unfolds umbrellas and spreads out blankets, because it knows with celestial mechanical precision that nothing but December can dislodge it. And December is on vacation. December is somewhere far away, drinking margaritas and playing poker with Santa Claus.

Anyway: sunsets.

I wanted to boost my Javascript skills, and I wanted to learn about Github, so I wrote a little program to show how fast the sunsets were ebbing noonward.

Here it is:


It uses browser geo-location to figure out where you are. If it succeeds, it can calculate sunset times accurately. It shows you today’s sunset and tomorrow’s so you get a sense of how fast things are changing. As a bonus, a stylized clock face shows two weeks’ worth of sunset times in blue. Finally, it shows you how long until the earliest sunset. At my latitude, that’s December 9th, a mere 80 days away! At your latitude, it may well be different. And I should mention that this page is possible because of Preston Hunt’s excellent SunriseSunset Javascript class. I had been working with some old Naval Observatory code, but it was miserable work cleaning it up. Preston came along and saved the day.

And if you want to help me fix it or report a bug, here is the Github repository:

Fork away!

LATE-BREAKING NEWS: I want to pass on my grateful acknowledgment of help from David Wey and Josh Natanson who, sure enough, did fork and improve my code on Github. Y’know, there’s something to this collaboration business. It’s a real rush when somebody magically reaches out and helps you fix something that you created. Thanks guys!

America’s Cup 2013

Have you seen any of the qualifying races for the America’s Cup? It’s worth watching.

The official America’s Cup racing starts this weekend, but the Vuitton Cup (which selects the challenger for the big race) just wrapped up. The new boats are just incredible. They are giant catamarans with immense rigid sails (airplane wings, really) and hydrofoil keels that pop them out of the water. And they fly. They’re moving at top speeds of over 50 miles per hour. They can sustain speeds of over 40 knots even as they come around a mark. As one of the commentators remarked, this leads to a new situation for sailors: high g-forces on the job.

But one of the most exciting things about the experience of watching the race has nothing to do with the boats themselves. It has to do with the way the race is presented on TV. Sailboat racing is a difficult sport to follow partly because so much that happens is hard to visualize. There’s no race track. Skippers can move on divergent paths for long periods, making it hard at times to even know who’s in the lead.

The augmented reality of overlaid computer graphics adds a lot of extra information, as this video from IEEE Spectrum makes clear: the speed of each boat, their tracks over the water, the wind direction, tidal currents, course boundaries, and more.

It’s easy to guess that, if people go for this kind of coverage in a big way, it will be applied to other sports. We already have the virtual “first down” line in football games. Imagine predictive baseball graphics showing you where that ball is going to drop in the outfield as the fielder runs it down. Or maybe other heretofore boring sports will get sexed up with augmentative graphics. Bowling with superimposed strike points, or curling with virtual dancing brooms. The mind boggles. Stay tuned!

Bonus coverage: here’s the Tech Crunch version of the story.