Life just got more … interesting

Ok, so not really life — just my physics. But this title flowed better.

So far today (it’s noon), I have made some real progress on a tricky problem we’ve been working on, that looks like it might soon give some very interesting results, possibly publication-worthy. This is very good. Also today, another paper appeared online with similar results to some of our work, from a different approach. This is potentially very bad. It’s 62 pages of heavy maths, so I’m not sure how bad at this stage. Preliminarily, though, it looks like at least some of our work is not in their paper.

So yes, things might start moving quickly now.

Arctic ice shrinks 14% in a year

New studies from NASA (JPL) and elsewhere show a 14% reduction in perennial (ie. survives the summer) Arctic ice in just one year, from 2004 to 2005. Supercomputer models had suggested that the ice (and, incidentally, polar bears as a species) would all be gone by 2070, but this is far faster even than those predictions.

This might be a good time to turn off a light, or take your bike to work tomorrow. Just a thought.

Co2 levels in ice cores

In the news today: new studies of gas bubbles trapped in Antarctic show that current CO₂ levels are higher than those for the last 800 000 years — and that the growth in CO₂ levels over the last 17 years is so fast that it would normally require over 1000 years of natural variation to produce the same change.

The past 800 000 years includes many ice ages, and interglacial warming periods between the ice ages. The CO₂ level fluctuates in step with global average temperature. So we’re looking at a change that in the last 17 years has been larger than that associated with a mere ice age (though luckily other changes are also associated with ice ages). But our CO₂ emission rate is still increasing.

Controlling computers with the mind

You may have heard of research being done on sensors which allow computers to be controlled with thoughts alone, as opposed to physical movement of the body (via, say, a keyboard). This research has immediate implications for people who are paralysed, but also longer-term implications for human-machine interfaces in general. At the moment it’s a pretty new field, and not very many people have actually controlled computers with thought alone.

I am one of those people.
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Seen in a Caltech corridor

Appearing in a Caltech corridor today: a transcript of Pluto’s concession speech. My favourite line: Dick Cheney was quoted as saying, “Today is a victory for the terra-ists”.

Beats the UFO News, a newsletter which occasionally mysteriously appears in random theoretical physicists’ mailboxes on campus. It’s a circa 1960’s, 30-odd page collection of articles including scientific explanations [sic] of devices such as power sources for UFOs that run off the fifth fundamental force.

Strings 2006

One more day of the Strings 2006 conference to go! It’s been a very intense conference, with many ideas and talks. I’ve gained some ideas which are at least somewhat related to things I’ve been thinking about, but I’m not sure how they’ll turn out.

I have been a little disappointed that there have been no “big picture” talks — string theory has had a slow year, and I would have been interested to hear what some of the big names were thinking about for the coming year. Though I suppose if anyone did have a big idea, they would have already published.

I’ve been contributing a little to Jonathan Shock’s very ambitious efforts to summarise proceedings at the conference, over at his blog. It’s turning into a useful reference (judging by his page hits, if nothing else), and it’s certainly be useful for me to review the talks. Though it is hard trying to write down succinct summaries of talks in other areas of string theory, especially when there are 5.5 hours of talks a day!
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Apportioning the Internet

The control of the infrastructure of the Internet is a controversial issue. Recently in the news was the refusal of ICANN, the governing organisation of the domain name system, to approve an application for the creation of a “.xxx” domain — aimed at sites providing pornographic material. The issue is deciding just who actually made the decision. But it’s definitely not the only issue of global fairness in Internet infrastructure.

The problem is that ICANN makes domain name decisions which are then effectively binding on the world (though China may be thinking of breaking ranks). But in general, the rest of the world has to follow suit if the Internet is to continue to work smoothly.
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ANALYZE your PostgreSQL databases!

I’ve recently been reminded, in no uncertain terms, of the importance of running the “ANALYZE” (or “VACUUM ANALYZE”) command periodically on a PostgreSQL database installation.

My problem:
Amongst other tables, a production database I administer has three tables: two moderately large tables, A⁽¹⁾ and B, and one quite large one (>700 000 records), C (for “Cross”), which is essentially the full cross product of A and B, with an additional piece of information for each tuple (record). So I’m associating some information with every combination of records from tables A and B.
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An unexpected thing on Del Mar Blvd

I was driving along Del Mar a day or two ago, just past Lake Ave near Caltech. It was dusk, and car headlights were just coming on. As I pulled up to the light, a huge bakkie (pickup truck) with raised suspension and huge tires pulled up right behind me, with its headlights on. I don’t think the brights were on, but the height of the truck put its headlights at exactly the right height to shine directly into my eyes, via every rear-view mirror I had.

Naturally, this was annoying. For a while I leant forward, till my neck got tired. Then I sat back, but with my hand raised between me and the rear-view mirror on the windscreen, thinking idle nasty thoughts about people who feel the need to turn perfectly normal cars into monstrosities.

But after a few seconds the strangest thing happened: the truck turned off its headlights. Since it was dusk, the only possible explanation was that the driver had seen my hand, worked out the problem, and turned off his/her lights. And in that instant my idle annoyance became a lot more complicated.

By being so obvious about the thing, I had turned a minor annoyance of mine into something so significant that the other driver decided to turn off the headlights. Was I really justified in doing so? Sure, it was the design of the truck that had created the problem in the first place, but what if the driver was only borrowing it? Or had realised only after buying it the implications for everyone else on the road? Since the driver was clearly aware of the effect it had on others, was he/she driving it out of necessity only? Ironically enough, getting what I most wanted had suddenly left me unsure that it was fair to be wanting it in the first place.

And what will the other driver do now? Since I was in a normal car, she/he will now be aware of the discomfit caused every time his/her truck is behind a car. Driving without headlights is clearly not possible, so will the driver be cringing each time a light turns red with some cars in front of him/her?

Such a simple act, so many questions!

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.