Extraordinary measurements

In the news today is the discovery of a planet about fives times the mass of Earth, orbiting a star 20 000 light years away from Earth.

That’s just amazing. Never mind the implications for the search for life, or any of that — the actual measurement is amazing. A quick back of-the-envelope calculation shows that an equivalent measurement would be observing something the width of a human hair, end on — about 0.05mm thick. It’s not easy seeing that with the naked eye more than about a tenth of a metre away, never mind on the moon.

Meanwhile, the people at LIGO are trying to measure changes in the path length of a ray of light, caused by passing gravitational waves, of less than a thousandth of the width of an atomic nucleus.

And the Large Hadron Collider, under construction near Geneva, will collide thousands or millions of protons a second, and track almost all of the vast numbers of particles each collision creates. We typically talk about atoms in groups of about 10^23 particles, but here we’re talking about tracking each individual particle.

And perhaps most amazing to me, we can make meaningful statements about the whole universe a tiny fraction of a second after the Big Bang, based on a few observations from a single planet in a single place in the universe, at essentially a single point in time in the universe’s evolution.

There are some really smart people out there.

When do we learn?

Education and learning are strange beasts. At school and university, people seldom understand even close to everything, and forget most of what they did understand soon after the final exam. But yet we trust doctors to prescribe correctly; professionals to know their jobs; or professors and teaching assistants to know what they are talking about. Where does this knowledge come from??
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Same-sex marriage in South Africa

As you may have heard in the news, on 1 December the South African Constitutional ruled that the wording of South Africa’s Marriage Act discriminates in an unconstitutional way against the rights of homosexual couples. The government now has to rewrite the legislation to allow same-sex marriage. The judgment is of course exciting and a triumph of South Africa’s ambitious constitution. But the text of the judgment raises some interesting questions relating to whether individual marriage officers with contrary religious beliefs should be required to marry same-sex couples.
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Movie short – Alive in Joburg

This is quite possibly the most bizarre thing I have ever seen. I’m still deciding whether it’s great or just really, really weird.

Anyway, it’s a movie short set in Johannesburg in 1990, in the midst of Apartheid repression. Only thing is … the repression is against aliens, as in UFO aliens.

It captures the grittiness of the Apartheid struggle pretty well, and looks very authentic (though there are a few giveaways that it was filmed in the last three or so years). But I can’t decide whether throwing in UFO aliens is interesting artistic license, or disrespectful to those that suffered.

Anyway, the movie is here, linked to from MilkandCookies

American Airlines figures me out

A quote from the first paragraph of an American Airlines promotional email I just received:

Dear Paul Cook,

At American Airlines, we know why you fly^® – to experience the sweet life of Belgium. Sample the chocolates, stroll the cobbled square and learn the charming customs of Brussels. We’ve even introduced an exclusive fare sale for AAirmail^SM and Net SAAver^® subscribers in your area so you can get there for less than you think.

Amazing! How do they know that?!? It is indeed true that the sole reason I fly is so that I can experience the sweet life of Belgium. Without the sweet life of Belgium, airplanes would be dead to me. Dead, I tell you.

Methinks someone has been trying a little too hard to work their registered trademark phrases into their emails…

In the belly of the beast

Over the last two days, I’ve discovered the Caltech steam tunnel system. Caltech has a reputation for having a large and interesting tunnel system (see Real Genius), and now that I’ve seen about two thirds of it, I can say it’s fully justified.

The steam tunnels contain pipes running from the physical plant all over campus for use in heating and cooling, as well as various other piping and cabling. This means that they go to virtually every building. Unfortunately, not all buildings have doors that can be opened or unlocked, but it’s still great for getting into all sorts of interesting places.

Yesterday I happened to find a 1996 map of the tunnels online, and an entrance that my South Master key opens. The map is pretty good, but I’ve found a fair number of tunnels not on it — mostly near newer buildings, or behind doors that I found open, but which were clearly locked when the map was made. There is still the northeast part of campus that I’ve not been to yet, but the rest I’ve explored fairly well.
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$100 laptops — now what’s the next step?

It’s starting to look like Nicholas Negroponte, founder of the MIT Media Lab, might just make his plan for a sub-$100 laptop work. Yes, that’s one hundred dollars. It has some very interesting innovations, and makes all sorts of interesting ideas possible.

The laptop is being developed by a newly-formed foundation, called One Laptop Per Child (OLPC) — have a look at the official FAQ. The idea is to make a really cheap but very usable laptop, which will be bought in quantities of at least a million, by governments, and distributed to schoolchildren. The idea is no less than, well, one laptop per child, anywhere in the world.
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False starts and things that matter

As the rebuilding in the wake of Hurricane Katrina starts, so too do people start asking questions about what went wrong in New Orleans, and the lessons that should be learnt. Notwithstanding a huge global warming wakeup call, the main conclusion seems to be that the US failed spectacularly to protect its poor and black citizens. The Economist front page calls it “The Shaming of America”, and editorials everywhere are calling it wakeup call to the nation.

The problem, though, with wakeup calls is that they so seldom lead to any real change. An excellent editorial in today’s USA Today compares and contrasts Katrina’s wakeup call with another of 40 years ago — the Watts riots of 1965 in Los Angeles. They were substantially more violent, but (insofar as I can tell as a foreigner) made affluent America aware of the depth of poverty and anger of the social and racial underclass of the country. The result? According to the USA Today editorial, poverty levels in Watts are actually higher today. And, of course, they weren’t the last race riots that LA was to see.
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Rafting the great Zambezi

Eight rafts, 23 rapids, 18 kilometres of the great Zambezi river. Two unplanned swims, one raft flip, about seven grade five rapids. Altogether, one hell of a day.

My brother and I spent Wednesday white water rafting. After the briefing and breakfast, the approximately 50 of us in today’s group head down to the river. Most of the rest of the people are here on wilderness group tours — travelling in a touring truck, camping at sites along the way. It’s the usual mix of backpackers — Australia, England, South Africa, a few from American and Germany.

The route starts within sight of the base of the Victoria Falls, with the Mist that Thunders hanging over the top of the gorge walls — all 700 feet of sheer rock. We spent the rest of the day in the gorge, with the Zambezi running swift and deep between towering cliffs, and the (very welcome) sun high overhead.
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Soduku solver

Soduku (Sudoku) is a Japanese number puzzle game that seems to be taking the world by storm. It’s played on a 9×9 grid. Each square can contain one of the numbers from 1 to 9 (inclusive). A given “problem” has some of the squares filled in, and you are required to fill in the remaining squares, satisfying the constraints:

Each row has to contain each of the numbers 1 through 9 exactly once.
Likewise for each column.
The board can be broken down into 9 3×3 squares (top-left, top-middle, top-right, etc.). Each of these has to contain each of the numbers 1 through 9 exactly once.

Anyway, these puzzles can get pretty tricky. Especially if you don’t know the third rule above — which until recently, I didn’t. Anyway, they’ve sufficient annoyed me now that I had to do something about it; so I wrote

The Langabi.name Soduku Solver

It’s not fancy, but is (in my opinion) very efficient. Enjoy!

Edit: Now available: an explanation of the method my solver uses, and the source code.