Jason’s Case of the Plane and Conveyor Belt riddle is confusing very smart people, so I thought I might explain it. First, go read Jason’s post, then come back here.

So, a lot of people assume that the thrust of the airplane is somehow effected by the speed of the magical conveyor belt it rides on. Let me first say this: it’s not, and rather than talk about how the thrust only acts on the air, and not the conveyor belt (the two are totally unrelated) I’ll talk about something I know well: skateboards.

Picture this – you’re standing on a skateboard that is riding on a treadmill. One person is standing in front of the skateboard on firm ground, and the two of you are holding a rope. This person pulls on the rope that you’re holding so that the rope moves exactly an inch per second, advancing you forward. No matter what speed the treadmill is going, as long as that person maintains the same rate of pull, you’ll advance forward an inch per second. Your skateboard wheels might go faster or slower in relation to the speed of the belt, but you’ll pretty easily advance forward. Change the rope to a stick, and the conveyor belt can travel in either direction at either speed and be just as irrelevant.

The airplane’s engines provide the forward force, pushing against the air behind their outputs. The air is like the person standing firm (as firm as air can be) and the engines pushing against that air provide the same kind of force that someone pulling on the rope provides. In both cases, the speed of the conveyor belt has no correlation with the force that the rope or engines produce against the air or the person standing firm.

Granted, in both cases, wheel friction will come into play. With a skateboard and treadmill, friction might be noticeable. With the kind of forces a jet turbine can produce the wheels would probably melt off before the engines noticed anything.

Are you going to SXSW in March and are you into Ruby on Rails?

Let’s plan an informal meetup where we can ask each other questions and place some names with faces. If you’re in, drop an “I’m in vote” so I can get an idea of how many of us there will be. If there’s enough, we may be able to reserve a venue. Once I know the level of interest I’ll take it to the next level, whatever that is. I already know of about six or seven people who have expressed interest.

Party at the moon tower!

These experiments with multi touch interaction make my bones ache I want it so badly. Seriously, this kind of human/computer interaction is the kind of thing that can change computing entirely, even more so than the mouse did. The examples of possibilities are simply amazing. I’m in pain, serious pain.

If you’ve sent me email in the past several weeks through my site’s contact form you should know I haven’t been ignoring you. My spam filters were a bit too aggressive and sent you all to the abyss. I’ll respond as quickly as possible.

The opening shots to this interview with Mark Romanek show Mark talking about a picture of Stanley Kubrick he’s had since high school. He describes Kubrick’s intensity in the picture as he watches an actor get set up for a shot. Romanek’s work is a lot like Kubrick’s – crisp wide angle panning shots, sharp highlights, embracing texture and light. It’s obvious that Romanek emulates Kubrick.

Mark Romanek’s work is pretty recognizable as well – most of his work shows up in music videos. The one I remember most vividly is a video done for Fiona Apple where it looks like he shot in a dark 70’s ranch style house with the kind of carpet I remember crawling on as a baby. It looks like he used a spot light mounted on a rig held camera, panning over the bodies of sleeping party goers, post party. For years I’ve thought about how he achieved the spotlight effect with such crisp detail and sharp light drop off, and I’ve tried doing the same in my own photography with varying degrees of success.

I’ve always really enjoyed Kubrick’s work, and I’m happy to see that Romanek has been a fan since at least high school, and has studied this one photograph and analyzed and thought about Kubrick’s dedication to detail. While I’m happy that Romanek’s work is influenced by Kubrick, I’m more happy that Romanek seems to have the same sort of intensity and passion for his work that Kubrick did. And despite his influences, it’s obvious that he can be quite original. I look forward to everything he creates.

Hillman Curtis shot and edited the video.

This cool terminal app for OS X reminds me of the Wang terminal with a 300 baud modem that my brother found in the trash. He let me dial into a BBS and it was shocked to my core with the possibilities, and I’ve been involved in exercising those possibilities ever since. Full screen mode on my 24" monitor is a thing to behold though. I think I want a 9" CRT just for this terminal application.

I’ve heard studies that say it’s not true, but I’ve never believed that the dry air in airplanes didn’t cause colds. I fly pretty often, and for the first part of last year I was flying nearly every week, and the entire time I had a killer cold that I couldn’t shake (which turned into bronchitis). I’d get nearly healthy, then fly, and be right back where I’d started. This article seems to find strong evidence that the dry air is the culprit, not so much the airplane. Combine that with high human traffic places like airports, and you’re ripe for disease.

Bruce Schneier wrote about the “failure of US-VISIT”, a blog entry about how the DHS has spent $15B on the US-VISIT program. Truth is, he’s wrong about the numbers. I’m not sure exactly where he’s getting his figure of $15B, but to date, the DHS has only received $1B for the program over the course of three years. He suggests that for the 1000 bad guys we’ve nabbed, they each cost $15M, which also isn’t true.


The program requires travelers to the US to submit fingerprints and photos in addition to normal customs routines. Out of the 44 million people processed, the program has captured 1000 people with criminal or immigration violations. No word on how many of those, if any, were terrorists. You can break down these costs two ways – $22/visitor, or $1,000,000/violator, but certainly not the $15M that Bruce suggests.

Now, I have to ask myself – am I comfortable with spending $1M per violator? I’m not sure I am. When I hear that only 1000 people out of 44 million were caught for whatever reason, that makes me wonder how effective the program is. Surely the percentage of “bad guys” is higher than that. And given that most of the terrorists who have committed attacks have had clean records, how will this catch those guys? There are terrorists who are brought up for a single purpose, one they’ll get a single chance at, and those guys will pass right through our filters. The entire idea seems about as pointless to me as the extensive security at airports – those who are truly committed to taking down a plane will always be able to just as those who are truly committed to getting into our country under false pretenses will always be able to.

Peter Diamandis, founder of the X Prize Foundation has been thinking about applying his X Prize Contest model to other types of challenges. The first X Prize Challenge put private citizens into space for the first time, and Diamandis thinks the same model could motivate people to build better cars and sequence the human genome.

Personally, I don’t think the X Prize would work for building a better automobile. The kinds of motivations are different – getting your team to be the first private citizens in space is a pretty serious motivator even without the prospect of a pot of money at the end (which would likely help your recoup your costs, not make you a space tycoon). Building the most fuel efficient car is a bit more mundane. The kind of hackers and engineers this kind of task needs won’t earn the same kind of geek cred that putting a man in space would. At best you might make some buzz on CNN, and eventually have your technology licensed or bought outright if you didn’t manage to scrape together your own production company.

Despite my misgivings – I hope it succeeds on any level. I think our country is in desperate need of gaining independence from fossil fuels for all the various political and environmental reasons. I look forward to the day when a toaster size box with a cold fusion reactor provides all the power my home and vehicles will ever need for the next fifty years, but I don’t think that the X Prize Foundation can motivate private geeks to make it. And nuclear reactions, even cold ones, aren’t the kind of thing you can just fiddle with in your garage, so my hopes aren’t high. This kind of technology will likely be in the grips of some kind of educational or governmental bureaucracy. The best we can hope for is some kind of “space race” fervor or a sort of Cold War like race with China, something that unifies groups of smart people to come up with clever solutions for the great good of their sect/user group/nation.

I’m not a political rocket scientist or anything, but did Bush essentially tell Iranians to fend for themselves in his State of the Union Address tonight?

Last year, Bush said this about Iran:

“Today, Iran remains the world’s primary state sponsor of terror — pursuing nuclear weapons while depriving its people of the freedom they seek and deserve. We are working with European allies to make clear to the Iranian regime that it must give up its uranium enrichment program and any plutonium reprocessing, and end its support for terror. And to the Iranian people, I say tonight: As you stand for your own liberty, America stands with you.” (Applause.)</p>

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Tonight, he said:

“Tonight, let me speak directly to the citizens of Iran: America respects you, and we respect your country. We respect your right to choose your own future and win your own freedom. And our nation hopes one day to be the closest of friends with a free and democratic Iran.” (Applause.) [Emphasis mine]</p>

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My brother in law and I have been talking politics a lot lately, and we both sort of agreed that we wouldn’t be surprised if the US invades Iran soon, though I’m shifting positions a bit. It seems like the political directives have cooled off a bit, despite Iran continuing to be more of a threat than Iraq ever was. My bet is we’ll slowly taper off our activity in Iraq, eventually turning our attentions to Syria. Iran will back down, and out in the sticks Al Qaeda will continue to elude us.