Harald Hanche-Olsen's blog

2007-04-01: Robin

More birdlife in the back yard: Far from exotic, this is a robin. Not what Americans call a robin, which is the size of a thrush. (Heck, the American robin, Turdus migratorius – and I am not making up the scientific name, is in fact a thrush.) This bird, Erithacus rubecula is about the size of a sparrow. Its distinctive song is usually the first to be heard in the morning and the last to stop at night. Like so many of my bird pictures, this one is from the back yard and taken through a window.

2007-03-04: Lunar eclipse

It started overcast, but a few rifts in the cloudcover gave us some hope. And sure enough, after a while the totally eclipsed moon started showing its face behind the thinning clouds. So we got the end of the total eclipse and all of the rest from there. A totally eclipsed moon is not very bright, being lit up only by sunlight refracted through the earth's atmosphere. So it's rather red and dim, and it is difficult to get the long exposures that are needed to produce very sharp pictures.

After a while direct sunlight was returning to the lunar surface, and it became impossible to take a picture showing the still eclipsed part without overexposing the sunlit part: The difference in luminosity is just way too big. A quick attempt at pasting together two pictures, each exposed for its own part of the moon, failed miserably. I need to sharpen my digitial photo editing skills and spend a lot more time on the job if I am to succeed at this task.

My final picture is taken about 45 minutes after the total phase of the eclipse has ended. About one-third of the moon is still in shadow:

2007-02-17: Waxwings

Flocks of waxwings (Bombycilla garrulus, sidensvans in Norwegian) are enjoying the berries left on our backyard hedge. These birds usually nest in Northern Russia and Siberia, then some of them often come here in huge flocks in the fall, stripping every berry off the rowan trees. They don't usually stay the winter, but we had an unusually warm winter, which may be why they are still here – except for a couple weeks of very cold weather, just over.

2006-05-07: Shelduck

Yes, spring is fickle indeed, but now it's here with a vengeance and very summerlike temperatures. We came across this shelduck (tadorna tadorna, or gravand in Norwegian) in a field on yesterday's bike trip. Now my bird books don't indicate that this is a rare bird, but I cannot remember ever having seen one of these in the wild before, so to me this was a treat. (Equipment: Canon EOS 20D, EF 70–200 mm 1:2.8L IS, 1.4x extender. The duck was far off: What you see above is just a pixel by pixel crop of the original eight mexapixel image, no reduction. The only editing done is a bit of contrast enhancement plus some unsharp mask. That lens is not at all bad.)

And speaking of birdlife: We have been seeing eagles on several bike trips lately. On one occasion we saw three, one of which flew across the road just in front of us. How frustrating then to think of all the camera equipment in the bike bags, just within reach but impossible to get out in time. But maybe we shouldn't obsess about recording everything we see.

2006-03-30: Spring is a fickle thing

Woke up to about 10 cm of fresh, wet snow today. And not only that – all of March has been unusually cold with just about perfect winter weather, day temperatures mostly just below freezing and a moderate snow cover. Very unusual for a coastal city like Trondheim. Just a year ago today, I took a picture of leaves sprouting outside. This is a useful reminder. Just like an unusually warm and early spring doesn't prove global warming, neither does the present cold spell disprove it.

2006-02-26: Another visitor in the back yard

Amazing isn't it, how much bird watching I get to do from my favorite chair looking into the back yard. This is perhaps not as exciting as our previous visitor, but I am not sure I have ever seen a wren in these parts before! (Norwegian: gjerdesmett; troglodytes troglodytes.) I probably have, but they're tiny, brown and hard to identify if you don't get a good look, which you don't half the time. The tail is usually quite distinctive, but I never got a good view of it. Still, I can't quite imagine this being anything other than a wren. Even more interesting to see it here in winter. If I am to believe the maps in my copy of the Larousse Guide to Birds of Britain and Europe (ISBN 0-88332-153-X), we're at the very northernmost end of their winter range here.

I was lucky to have the telephoto lens already on the camera (a 70–200 mm f/2.8 with image stabilizer, and a 1.4x extender), since I had just been trying to photograph sparrows frolicking in and on the hedge.

2006-02-05: Freedom of speech

Once again, I feel compelled to write on a political issue. Angry mobs have burned the Danish and Norwegian embassies in Damaskus, in response to a series of caricatures of the prophet Mohammad published several months ago in Jyllandsposten and later in the Norwegian Magazinet (“The Christian newspaper” they call themselves, though Magazinet is hardly an influential paper, as far as I know). Not only the people responsible for publishing the caricatures received death threats, but so has the head of the Norwegian journalist's union, though all he has done is to defend the freedom of speech.

The protesters demand an apology from the Danish and Norwegian governments.

Meanwhile, Norwegian Muslims are calling for limits on the freedom of speech, asking whether freedom of speech is really more important than respect for other people's religion?

The question demands an answer, and mine is yes!

Freedom of speech did not come easily to the western world. Many people have died for it, and more have suffered, in opposition to secular authorities and the church both. It is an essential condition for the battle of ideas to lead towards truth and not away from it. Without freedom of speech, we stand not a chance at solving the many problems humanity is currently facing. In short, we must never give in to the rabble and apologize for the very fundament of our culture – our freedom of speech. And get this: The freedom of speech has side effects, one of which is that some people will hear things they find offensive. This is no reason to curtail it.

Public discourse in our culture takes many forms. Thoughtful commentary on the one hand, and caricatures and ridicule on the other, both have their place. The latter should not replace the former of course, but neither must we ban it: For some things truly are worthy of ridicule. But the law is not the right instrument for deciding which things we are allowed to laugh at. And neither is the burning of embassies.

How ironic that some Muslims in the United Kingdom choose to use their freedom of speech to advocate the killing of others for exercising the same rights. In Norway, they would run afoul of one of the limitations to free speech in our country: It is illegal to incite others to commit crimes.

2006-02-04: A visitor to our back yard

Look who came visiting in our back yard today! Unless my ability to identify birds has failed me, this is a goshawk (Norwegian: hønsehauk; accipiter gentilis if you prefer). It spent a minute running back and forth along the hedge, occassionally sticking its head in, then pulling out, jumping to the side and repeating the procedure. I suppose there was a mouse in that hedge which the hawk wanted for lunch.

I managed to get the telephoto lens on the camera and shot five pictures in as many seconds before the hawk took off and went elsewhere without its lunch. Unfortunately, the settings on the camera were not optimal, but I obviously had no time to change them: The sensitivity is a bit high (at ISO 1600), so there is some noise. And the window that was between me and the bird did not help.

All this happened while the wife was out. She is jealous, of course.

2005-10-20: Doubly mean? The double mean value theorem

A colleague came across some references to the double and triple mean value theorems today. As neither he nor I had heard about these theorems before, we were naturally intrigued. These theorems were stated in a form clearly optimized for their use in estimating various quantities, and so were not immediately recognizable as any form of mean value theorems. Worse, it was not even clear to us precisely what they said. Besides, although they certainly looked right, some obvious approaches to a proof did not work out. And of course, no proofs were given, these elementary results presumably being well known, at least to the authors of the papers. So I sat down and thought about it for a while, and came up with statements of these theorems that actually look sort of like mean value theorems, and from which the estimation versions of the theorems are easily derived. Moreover, the proofs are quite simple and aesthetically pleasing. I am sure these proofs have been invented many times over, so no claims to originality are made here. This stuff is just too hard to write as HTML, so please look at the attached PDF file if you're interested.

2005-10-11: Why is this blog designed with such a big font?

No, dear reader, it is you who chose this font size. The font is the size it is because I did not override your choice.

What – you didn't choose a font size, you say? Yes, you did, if only by not changing the default setting in your browser. Just try it: Find the preferences in your browser menu, look for the fonts section, and try different font sizes until you're happy with the result.

Unfortunately, if you do this, many web pages will end up in a font too small for you, because they have been designed by people who think they know better than you do what you need and want. Complain to them, not to me. I am going to continue to give you the font size you asked for, whether you want it or not.

Jacob Nielsen agrees with me. So do many others, as he has recently found out.

2005-10-05: Filling an important gap in the literature

I have long been a fan of the apocryphal tale of the book review stating that the book under review “fills a much needed hole in the literature”.¹ So imagine my delight when I came across a book in the bookstore quoting a review on the back using almost the same phrase: It should fill an important gap in the literature.

The book in question is entitled Introduction to Relativity by John B. Kogut. I have highlighted the phrase in the picture for your reading pleasure.

I shall adopt a similar phrase as the motto for my blog from now on.

¹Allyn Jackson: Chinese Acrobats, an Old-Time Brewery, and the “Much Needed Gap”: the Life of Mathematical Reviews. Notices of the AMS 44, 330–337, March 1997 (reqistration required).

2005-04-10: Life, death and moral values

Up to now, my blog has hardly touched on political issues. It is not likely to in the future, at least not frequently – but now I find myself provoked into writing on a political issue anyway, even though I know full well that hardly anybody reads my blog. Or rather, an issue of religion and morality. To some people, there is no difference. Maybe they're right: There is after all no question that political decisions have life and death consequences.

A bit of background first. I am an atheist, and have been so for most of my life. This means that I do not believe in the existence of any god. (I do not capitalize the word, because there are many religions in the world, and their concept of god is not the same.) Of course, I am not so stupid as believing I can prove that there is no god, only that I know of no compelling evidence for the existence of such a being, and therefore find believing in one useless and counterproductive.

I also consider myself a philosophical materialist, which means that I believe that the material world is the only world there is. All our beliefs, our values, our loves and sorrows, even science and mathematics, are just manifestations of our material brains existing in and interacting with a material universe. Which does not make them any less real or valuable: But beliefs that run counter to fact can be downright harmful.

Which brings me to the topic of today's post. (I apologize for the length of this. I just don't know how to make it any shorter.)

Being who I am, I have always had some difficulty understanding the world from the perspective of the religious. And yet I feel I should make the attempt: After all, the majority of the world's people are religious. Particularly alien, to my mind, is the American so called Christian Right. Recently, the web site www.breakpoint.org was recommended to me as a good perspective on the world as American Christians see it.

Naturally, I was intrigued and went to have a look.

I find this stuff hard to read: Oh, I understand the English very well, thank you very much, but still, it's a bit like these folks are speaking Chinese or something. Their thought patterns are just too alien for me to follow.

That is, until I came upon the article Material Girls – How Feminism Betrayed Terri Schiavo by Leslie Carbone.

This is the article that provoked me so much. In fact, this is the most outrageously bigoted piece of writing I have ever stumbled across in my life. Yes, I looked up bigoted in the dictionary to be sure, English after all not being my mother tongue: A bigot is a person obstinately or intolerantly devoted to his or her own opinions and prejudices. Based on this one article, that in my opinion describes Leslie Carbone to a tee.

Just read this opening sentence:

On March 31, 2005, thirty years after feminism's hey-day in the 1970s, a woman died from dehydration, on the orders of her adulterous husband, who was supported by the courts in his quest to end his wife's life.

Can you say “loaded language”? I knew you could.

To be sure, the Schiavo case is a tragedy. But wherein lies the tragedy? That is where the opinion divides.

The death of Theresa Schiavo was of course tragic. But that death – the death of the person – occurred in 1990, not this year. That is when most of her brain died, and with it everything that made her who she was. Only her body – including the brain stem, which is the reason for all the controversy – lingered on until this March. From that day on, Michael Schiavo was a widower in fact, if not in the eye of the law, even if it took him years to come to terms with it. The second, smaller, tragedy is the aftermath, including numerous court cases and the break between Michael Schiavo and his parents-in-law. But the recent expiration of Theresa Schiavo's body is no tragedy at all, for Theresa was already long gone.

I could go on, but it is better for you to read this article from the New England Journal of Medicine, which explains all this much better than I ever could.

So, adulterous? Give me a break. What is clear is that Michael Schiavo, as well as Theresa's parents, maintained their contact with Theresa (what was left of her), visiting her and taking active part in her care, for years, which is much more than most people would do in a similar situation. Michael Schiavo even educated himself as a nurse so he could take a more active part in Theresa's care. That he found another woman seven years later, who he now lives with and has two children with, can hardly be called adulterous, no matter that he was still legally married to Theresa.

And was the feeding tube removed on Michael Schiavo's orders? Not at all. This was ordered by the courts. Michael Schiavo had taken this case to the courts precisely because he could not, or would not, decide it alone. If Leslie Carbone had been even remotely interested in facts, she could easily have read the court documents. All the court decisions are available online, together with plenty of commentary, at Abstract Appeal. But no, she obviously didn't want her case sullied by facts.

What should be clear even on a first reading, is that the so-called “affidavit” of Carla Iyer is hardly credible: It portrays not only a totally selfish, almost murderous Michael Schiavo, denying even basic care of Theresa, but a conspiracy of doctors and nurses all going along with him in this. If you read the court decision of September 17, 2003, you will find that the judge has carefully considered this testimony, and dismissed it as lacking all credibility. I will not dirty my blog by quoting from it, or even linking to it. (But google can find plenty of copies for you if you must look.)

Leslie Carbone goes on:

That court after court could find in favor of the death desired by a woman's cold-hearted, adulterous husband over the life desired by her loving, heart-broken parents shows the corruption of modern culture. Theresa Schiavo's death also marks a milestone in modern culture's embrace of feminist values.

Here it is again. Not only adulterous (again), but cold-hearted as well. Whereas Theresa's parents are loving and heart-broken. I am sorry, but I don't see a shred of evidence supporting this difference in portrayal of the parties to the dispute. Leslie Carbone's vicious attacks on Michael Schiavo in a highly public forum hardly strikes me as consistent with Christian values, but then not being a Christian myself, I will not presume to lecture on Christian values to Christians. Instead, let me state that such an attack would not be consistent with my values, or any value system that I can sympathize with.

The corruption of modern culture? I, for one, do not see anything corrupt in the notion that people can choose to forego life extending treatment when there is no hope of further life. All the courts have done is to determine that this is what Theresa Schiavo would have wanted. And, contrary to popular belief, they did not come to this conclusion on Michael Schiavo's say-so. On the contrary, they recognized his conflict of interest, and relied instead on the testimony of others who knew her well. This is what “court after court” did, and this is the finding they came to consistently, in accordance with Florida law. That so many people on the Christian right evidently have no respect for the court's decision, or their competence to make such decisions, or indeed for the right of the individual to choose the manner of their death even the most extreme of circumstances, is nothing short of scandalous.

Not to mention, these same people tend to have no similar qualms with respect to the death penalty. Go figure.

You may have noted a reference to feminism in the two brief passages I quoted. Yes, an all out attack on feminism what Leslie Carbone is really about here. The litany of sins and problems of the family, and society at large, that she lays at the feet of feminism is impressive. I'll leave most of it alone – no doubt, others will pick these arguments apart – but I have to comment on this little bit:

[...] a materialistic view of life, according to which its value is not absolute but is instead subject to its perceived utility.

As I explained in the beginning, I profess a materialistic view of life, as on everything else. I also value life. But what is this about perceived utility? I don't believe Leslie Carbone has ever met a philosophical materialist, let alone talked to one. This unbridled nonsense is just a figment of her own fantasies of what materialists must be thinking, nothing more. Okay, so I don't see the value of life as absolute. There – I have said it, are you happy now? I have no qualms about crushing the occasional insect, though I only do it if they go places where I don't want them, or by accident, because after all I do not carefully sweep them away from the path before me when I walk. I also eat meat. And I eat salad. The lettuce was alive too, you know. Oh, but now I'm confusing Buddhism with Christianity? Is it so that only human life has absolute value in the Christian world view? But what is human life? To me, human life – the kind that has value – lies in the cognitive abilities. This is not to say that a Nobel laureate is more valuable than either Leslie Carbon, myself, a baby, or a mentally retarded or otherwise handicapped human. Ranking the value of human life on such flimsy evidence flies in the face of everything that makes us human. We must indeed err on the side of caution when we decide who is or is not human. But when there is no brain there anymore to support cognition, when indeed most of the brain is replaced by spinal fluid, then the human being is gone. Theresa Schiavo died fifteen years ago. At the other end of life – the fetus – I see it the same way: It is only as the brain begins to form and function that a human being is gradually coming into being. That has obvious consequences for my views on abortion, but I'd better stop here, before this blog entry gets out of hand.

I might add that when I say that human life has value, this is not something I see as a necessary consequence of the materialistic world view. On the contrary, the universe is notorious for not caring whether we live or die. But our fellow human beings do, because our biology and our culture conspire to make us that way. We have the ability to choose to reject that heritage, but fortunately, most of us don't. Moreover, we take steps to protect ourselves and each other from those who do, and rightly so.

2005-03-30: Spring is here

Yes, spring is really here. Not only in my office, where the mother-in-law's tongues are blooming, but outside as well.

It's almost enough to compensate for the misery of two hours wasted chasing down another IE CSS bug, which caused text to disappear on a web page I'm maintaining. (If you run IE6, and resize your window to be narrow enough so that the two pictures don't fit side by side, you'll see another amusing bug.)

I know what to do: Go home, sit outside in the sun, and have a beer.

Added 2005-04-02: Uh, or maybe this spring thing is just a cruel hoax? ☺

2005-03-17: Have Norwegian media no sense of culture?

Today, it was announced that Peter D. Lax will receive the 2005 Abel prize. The number one national television channel, operated by the Norwegian Broadcasting Corporation (NRK), did not see fit to spend even five seconds on this news in their main 7 o'clock newsprogram today. Have they no culture then? It seems not. I am really disgusted. It is hard to believe this is the same country that fostered such giants as Niels Henrik Abel and Sophus Lie.

Added the next day: Apparently, as far as I have been able to find out, none of the major newspapers in Norway mentions the Abel prize, either in their paper or their online editions. More surprising still, not even the New York Times has mentioned it, even though Lax has spent his entire professional career New York University (see their press release). One glimmer of light in the overwhelming darkness: A popular science program at NRK – Schrödinger's cat – did quite a nice job of presenting the prize winner. This program runs just after the news, i.e., in prime time.

Added 2005-03-29: the New York Times has discovered what is going on after all, and published a conversation with Peter Lax (free registration required; after a few weeks, maybe you need to pay).

2005-02-28: Omar Khayyám and the cubic equation

Went to an interesting talk about Omar Khayyám last Tuesday, by K Razi Naqvi, a physics professor. He stated that Omar Khayyám was not really a great poet as Persian poets go, and moreover it is not at all clear that he wrote all the poetry attributed to him. Be that as it may, to me the discussion of the mathematics of Omar Khayyám was much more interesting. I am only moderately interested in poetry, and I am certainly not qualified to judge either Khayyám's poetry or the authenticity of his alleged works.

Omar Khayyám's solution to one class of cubic equations appears in the picture. All you need to do to solve the equation

x³+b²x+b²c=ax²

is to construct the circle and the hyperbola, then find their three nontrivial intersections. (The trivial one is the one on the left, which is known by construction.) I wrote up a few more details with a better picture (pdf). As I explain in the writeup, Omar Khayyám did not have variables, much less modern algebraic notation, so he did all this in words. A remarkable achievement. (But of course, he knew the classics, including Euclid.)

2005-02-16: Still best viewed without Internet Explorer

Almost two years ago, I wrote about the problems that Microsofts lack of standards compliance cause for web users and publishers alike. These problems are as much alive as ever, as evident from a Register article by Opera founder Håkon Lie: Get real about interoperability, Mr Gates.

Added 2005-02-18: I just cannot resist linking to today's User Friendly cartoon.

2005-02-15: I'll have more time two weeks from now

I'm awfully busy right now. But in a couple weeks, I'll be done with the work that is bothering me now, so I'll have more time. Therefore, if you ask me to do something this week, the answer is “sorry, I don't have the time right now”. But if you ask me to do something in a couple weeks, I'll agree, for I will have more time on my hands then.

Right? Wrong.

For almost as long as I can remember, I will be less busy in the near future than I am right now. Part of the problem is that I tend to be much more liberal about making promises to do stuff in the future. I'll have more time then, remember? But when the future arrives, I have already promised it all away, so I'm just as busy as ever.

And now the research has been done to confirm this. Gal Zauberman and John Lynch have published a paper which puts this simple observation on a firm footing. I'll read it for sure – as soon as I can find the time to do so.

And while we're discussing time: I finally got around to reading Thomas Hylland Eriksen's book Tyranny of the Moment: Fast and Slow Time in the Information Age. It ponders the question: Now that we are so surrounded by time saving devices, why do we have so little time on our hands? Where is it all going? We're being flooded with information, all of it sized in tiny chunks because nobody has the time to read a long article anymore. What we need is more slow time, since the fast time which fills our days gives us no time to think and no time to do anything original. Or to actually live our lives.

References:
Zauberman, Gal and John G. Lynch, Jr. “Resource Slack and Discounting of Future Time versus Money”. Journal of Experimental Psychology: General 134, 23–37 (2005). The paper is available as a PDF file from either author's home page, or at doi:10.1037/0096-3445.134.1.23 (what is a DOI?).
Thomas Hylland Eriksen: Tyranny of the Moment: Fast and Slow Time in the Information Age. Pluto Press Ltd., 2001. ISBN 074531774X.

2004-12-28: The isodiametric inequality

The isodiametric inequality states that, of all bodies of a given diameter, the sphere has the greatest volume. The picture contains the essence of a simple proof for the two-dimensional case. Basically, the area is written as an integral in polar coordinates, the integral is split in two, and then a simple application of Pythagoras' theorem and the definition of the diameter clinches the result.

I wrote up a more detailed account as a single page PDF file.

I learned this proof from prof. Frederic W. Gehring. Unfortunately, he cannot remember where he learned it. If you know who first discovered this proof, or have seen it elsewhere, please send me an email.

Added 2005-01-05: Gareth McCaughan has pointed out that the proof can be found in Littlewood's miscellany. I should perhaps not be surprised, since prof. Gehring was Littlewood's student once. Still, it is unclear where Littlewood had it from.

2004-06-12: Is blogging basically a selfish activity?

According to today's User Friendly cartoon, it is. See if I care. Some people think that even acts of altruism and self-sacrifice are selfish if you dig deep enough. I don't care to dig that deep; and besides, not that many people read my blog anyway, do they? (But I enjoy the illusion that they might.)

2004-06-10: The Golden Ratio: Not so golden after all

I have always been somewhat skeptical about claims that the golden ratio is the most aesthetically pleasing of all proportions, and that this has been known by artist since antiquity. Don't get me wrong: The golden ratio, defined as the positive solution to the equation g²−g−1=0, has many mathematically pleasing properties, not least among it as the limit of the ratio of consecutive Fibonacci numbers. But the aesthetic personality of the golden ratio has always left me mystified.

Now I have learned that my skepticism is in fact well founded. The article Good stories, pity they're not true by Keith Devlin explains it all. Plainly and simply put, it's all a myth. What's more, this has been known at least since George Markowsky published a paper in the College Mathematics Journal in January 1992.

While you're at it, others of Devlin's articles, in the column Devlin's Angle at MAA Online, are quite readable too. Be sure to read The best popular science essay ever.

Oh, and the 1992 paper I mentioned:
George Markowsky: Misconceptions about the Golden Ratio, The College Mathematics Journal 23, no. 1 (1992), 2–19.
If you're in an academic institution with access to JSTOR, you can find the paper there. I would give you a direct link, but it appears that they embed subscription information into the URLs at that site.

2004-06-08: Venus transit

There will be no other till the twenty-first century of our era has dawned upon the Earth and the June flowers are blooming in 2004. What will be the state of science? God only knows.

– William Harkness, U.S. Naval Observatory 1882

I lifted the above quote from forskning.no's page (in Norwegian) on today's Venus transit. It highlights the unique nature of this event. Venus transits – the planet Venus passing in front of the sun – happen twice every 120 years or so, with eight years between them. The previous one was in 1882, the next one will be in 2012, and the next one after that well into the twenty-second century. Seeing a small black dot in front of the sun doesn't sound all that exciting, but it felt very special all the same. I looked at it regularly from about the middle of the event to the end. The whole transit took about 6 hours.

For another very nice page on the event (also Norwegian, but with pretty pictures), see the page by astronomi.no.

(Addendum, the day after) Nice picture at NASA's APOD (astronomy picture of the day). Be sure to follow the links, particularly to David Cortner's Transit of Venus photographs.

2004-05-31: Science and The day after tomorrow

I just couldn't resist. I went to see The Day After Tomorrow. The film is controversial of course, though most people (those who know) agree that the movie vastly exaggerates the likely consequences of global warming. Some people think this is okay, everybody knows this is Hollywood, they expect a certain amount of departure from reality, it's good entertainment, and it serves to highlight a serious problem.

Sorry, but after seeing the movie I don't buy it. It's a violent movie, in the sense that it shows nature doing some large scale violence to people and property. Sure, I know nature is capable of killing people by the million, but not in this way. In fact, the biggest violence of the movie was against science. Satisfying as it may be to see Los Angeles being shredded by giant tornadoes or Manhattan being flooded by monster waves, I found myself unable to enjoy the spectacle because the science was so astonishingly bad. I was in fact so perturbed by the movie's radical departure from reality that I never even noticed whether the acting was good or bad, nor was I moved by the personal tragedies and triumphs of the characters.

They had approximately two facts right: There is some concern that melting of the polar ice caps as a result of global warming might weaken the thermohaline circulation (THC) which contributes so much heating to Northern Europe in particular, and it is now recognised that climate change can happen much faster than previously thought. Unfortunately, this reasonable portrayal of possible science was over before I had finished settling into my seat.

How about having the THC weaken so suddenly that widely scattered buoys in the North Atlantic register a 7 °C drop in sea temperature over a few hours? And this triggering three continent size storms covering all of the northern hemisphere, roughly between 40° and 70° north in a matter of days? And these storms, with a general structure like hurricanes, sucking cold air at -100 °C out of the stratosphere down to ground level, flash freezing everything in its path? Including a flag frozen in mid-wave? Puh-lease, give me a break! Didn't anybody explain to these bozos that bringing cold air down from high altitudes will compress it, and thereby heat it? Don't they have the experience from childhood of a bicycle pump going warm after a few minutes of vigorous pumping?

I don't want to get into the details of all the bad physics in this movie. I'll leave that to an expert, namely the keeper of the insultingly stupid movie physics web site. I look forward to reading their review of the movie. In fact, I sort of lied when I said (or implied) that I didn't enjoy the movie: I did enjoy it somewhat, in the same way I enjoy a really bad old monster movie occasionally. But I enjoyed the walk to and from the movie theatre in a beautiful sunny evening more.

PS. I cannot resist commenting on the quality of the Norwegian subtitles, this being something of a pet peeve I have. Now I didn't watch the subtitles too carefully, since I can usually understand the spoken English quite well, and besides I was too busy grumping over the science, or lack of it. But clearly, the translator had no idea what a mainframe is. That's understandable, perhaps. But couldn't they ask somebody who might know, rather than making a wild guess and translating it to "hovednettet" (which would roughly translate back into English as "the main net")? That they consistently misspelled the Norwegian word "forsyninger" (for "supplies") as "forskyninger" just added to my sour mood. Someone ought to introduce these translators to spell checkers.

2004-05-25: An unusual visit

Just to drive home the point that no topic is too small or insignificant for this blog.

Today, an white-tailed eagle flew right over our building during lunch. White-tailed eagles (Norwegian: havørn) are not that uncommon on the coast, but I had never seen one in the city before. These are huge birds, with a wing span usually well over 2 meters. The eagle came from the north. It was being harassed by a handful of gulls and a couple of crows, all of which looked gnat-sized next to the eagle. Quite a sight – it made my day!

2004-04-16: Spamfiltering and HTML

Don't send me HTML mail. If you do, chances are good that my spam filter will classify it as spam, and I will never see your email.

Filtering spam is the wrong solution to the spam problem, in the sense that it is not a final solution, only a desperate holding action in the seemingly endless war between spammers and email users.

But then these are desperate times, and I, along with everybody else, use whatever technique is available to ensure that email will remain useful to me, if only for a short while longer. The only longterm solution is to change the rules of the game so that spamming becomes too expensive for the spammer.

So why does my spam filter catch HTML mail?

The reason is very simple: I use one of many available Bayesian spam filters. Namely, SpamBayes. Briefly put, after installing the filter, I showed it a couple thousand spam messages, telling it Remember what these look like. This is spam. I also showed it a similar number of legitimate mail, saying This is ham.

And then I let it loose on my incoming mail.

And lo and behold, as many spammers use HTML and very few of my legitimate correspondents do, the filter takes HTML as being a very strong indication of spamminess in my email and then it throws it in the spam bucket.

I actually like it that way.

HTML is for web pages, not for email anyway. I don't read email with a web browser. I use an email program instead. So when you send me HTML email, I have to either try to find the text between all the HTML tags, or I need to save the mail in a file and then use a web browser to look at the file. This is too much trouble, so I had already acquired the habit of ignoring HTML mail unless there is a very strong indication that I should go to the trouble of reading it anyway. But now, more often than not, my spam filter makes that decision on my behalf, and I am happy to leave it that way.

But what about sending the message both as text and HTML?

Then I can choose which one to read, and everybody is happy, right?

Yes, that would work for me. But my spam filter does not agree, and right now I cannot live without it. This is what spammers do to us: They make us tear apart this wonderful infrastructure that the Internet is providing to us, just so we can stay sane and get work done. We are doing this to ourselves, but yet we have little choice, at least in the short run. In the long run, we can only hope that solutions will be found. Many people are working on solutions, but most of the solutions are only short-term solutions — mere turns of the screw in the arms race with the spammers. Any long-term solution must of necessity change the ground rules of email exchange, and inertia coupled with an aversion to pain will stop that from happening soon.

Meanwhile, please excuse me while I install this mine field around my mailbox. No, don't step that way! Don't

2003-12-18: Postmodernism Generator

I found the link to this Postmodernism Generator in a book review. The generator will produce a new, grammatically correct but totally nonsensical, postmodernist essay — with endnotes — every time you visit the site. Enjoy!

The book review in which I found the link is worth a visit too. How could it not be worthwhile, being written by Richard Dawkins and reviewing the book Intellectual Impostures by Alan Sokal and Jean Bricmont? After you have read the book, as I have, you will enjoy the postmodernism generator all the more. If it doesn't make you puke.

2003-04-23: Best viewed without Internet Explorer

«Best viewed with Internet Explorer.» This always was the hallmark of the «web designer» who did not understand or care about the standards of the web; they would write their web pages so that they looked good in their own particular browser, usually IE. More often than not, they would rely on some non-standard extension to HTML supported only by IE in order to achieve the wanted effect. If they got complaints about it, they would respond by putting a notice on their web page. «Best viewed with Internet Explorer.»

When I first learned about Cascading Style Sheets (CSS) years ago, I thought this was the neatest invention since - not sliced bread, since I don't think sliced bread is all that neat - but since, say, the planimeter. I instantly decided to use it, and almost as quickly gave it up as hopeless. Why? Because none of the major browsers supported the whole standard, and, worse, the parts of the standard they did follow, they managed to screw up royally, more often than not.

But now, I thought, everybody has had years and years to implement CSS, so finally we can begin to do web design the sensible way. I started out with these blog pages as a test bed, and I thought it worked fine. Until someone told me that it doesn't look right in Internet Explorer.

The truth is, I had not bothered to test my pages in IE. You see, for a long time IE used to be the most reliable and standards compliant browser on the planet (apart from its nonstandard extensions that is). So I did not really consider testing with IE as necessary. Well, no more, it seems. Apparently, both opera, mozilla and Netscape have far outstripped IE in the standards compliance department. Just have a look at these pages on the CSS support of various browsers, and marvel as I did over the sea of red associated in particular with IE, though none of the others are perfect either.

As a result, these pages did not look right in IE, and hence the title of today's blog entry. I have managed to find workarounds for most of the problems. But there are still problems with floats: IE makes space for them, but does not display them. I have no idea what triggers this, and how I can work around it. Until I do, these pages are best viewed without IE. (Well, this page has no floats on it, but my FLT sub-blog (follow the links in the 2003-02-04 entry) does, and none of the floats show there using IE.) I don't have the time to investigate this in depth. If I don't find a better solution, I might generate a simplified version of the page instead, but it will have to wait. At least, with this rant, I got to blow off some steam. If you want to learn more about the problem and possible solutions, it looks like the noodle incident is a good place to start.

Addendum (later the same day)

Well, I figured out how to get around the IE bug after all: When a float is inside a container and the outer container has a background (colour or image), then either both or neither of container and float must have position: relative set, or else IE will put the background of the container in front of the float. In one word: Duh! This kind of silliness is what makes web design so exciting.

2003-04-19: Differential forms and the polar planimeter

Planimeters are mechanical devices for measuring the area of a figure drawn on paper. How and why do they work? It is possible to figure it out by geometrical reasoning, by considering the area swept out by an arm of the planimeter. If you work a lot harder, you should be able to do it by employing the mathematics of first-year calculus including Green's theorem. That seems to be surprisingly difficult, but not impossible if you are clever enough. I found that a proof using the language of differential forms becomes quite easy, albeit not as intuitive as the geometric proof. So I wrote it up on a single page (pdf). I hope you enjoy it.

If you want to learn more about differential forms, it's hard to beat the excellent book by Harley Flanders: Differential forms with applications to the physical sciences, Dover 1989, ISBN 0486661695.

2003-02-04: On a "proof" of Fermat's Last Theorem

A strange tale concerning a professor of medicine, a professor of social anthropology, and an elementary proof (they say) of Fermat's Last Theorem. Visit my sub-blog on this affair if interested. Even if something new happens, I probably won't update the present entry.

2001-04-01: An April fool's joke

During the spring of 2001, there were many rumours at our university about the new rule for calculator use at our university: For many exams, only a specified, simple calculator would be allowed. This much was clear; what model calculator was the subject of the rumour. On April 1, I put together this page supposedly revealing the make and model. The text is in Norwegian, but you may still admire the picture.