Archive for January, 2006

Roast Potatoes

Tuesday, January 31st, 2006

Apparently somebody wanted to know how I make my roast potatoes. The trick is in the parboiling.

Use starchy (as opposed to waxy) potatoes, and make sure they aren't too old.

Peel the potatoes and cut them into pieces an inch or two in diameter (bear in mind that they will shrink a bit in the cooking process, so make more than you think you'll need).

Put them into a saucepan for which you have the lid, sprinkle on some salt and put water in the pan until the potatoes are just covered. Heat until the water is boiling and let it continue to boil for a couple of minutes, until the tip of a sharp knife easily penetrates the potato to a depth of a few millimeters.

Now here's where the lid becomes important. Pour out the hot water and put the lid on. While wearing oven gloves, hold the pan (and the lid, so it doesn't come off) and shake vigorously for 20 seconds or so, to rough up the surfaces of the potatoes.

Heat some sort of oil or fat in a shallow metal tray in the oven for a few minutes. Goose fat is the best if you have it. Put the potatoes in the hot oil and turn them so that they are completely covered in oil. Sprinkle with a bit more salt, and then roast in an oven for about an hour at 375F (give or take - you can cook them hotter or colder if you have the oven at a different temperature for cooking something else at the same time, just adjust the time appropriately). About half way through take the potatoes out, turn each of them upside down (don't try to cheat and turn the whole tray upside down at once - they'll fall out). Then put them back in to finish cooking.

Serve hot, and with meat (to people who eat meat).


Cartwheel galaxy

Monday, January 30th, 2006

I think what I like most about this image isn't the high technology involved in combining images of the same structure from 4 different telescopes, nor even the deep insights into the physics of galactic collisions that it provides. What I like most about the picture is all the pretty colours.

More specifically, I'm fascinated by what it means that this picture is so colourful. What it does mean is that there within this galaxy there are regions of space where qualitively different things are going on. There's got to be at least 7 or 8 different colours in that picture. Each of these colours represents a region of space with a particular distribution of dust and gas and stars of various different sizes. All the different colours mean that there are lots of different such distributions. In some places, space is mostly full of dust and gas. In others, there are stars which are mostly very old. In others, there are stars which mostly very young. Why different areas of space have such different characteristics is a mystery to me - that's why I find the different colours so fascinating.

Here's another fascinating picture. This isn't a painting, an artist's impression or a computer graphic, it's a photograph (albeit a very high-tech one) taken by the Hubble Space Telescope. If you had a sufficiently powerful telescope and pointed it in the right direction, that's exactly what you'd see. It's really hard to get a sense of the incredible scale of this galaxy from the picture, but it's about 50,000 light years across. That means even the finest details you can see in the dust rings surrounding the galaxy are each hundreds of light years across. This thing is just unimaginably big, yet the size of these fine details compared to the size of the whole thing makes it look like something on a much more familiar scale. One would expect something that big to be quite smooth but that isn't the case.

It seems that the universe has a great deal of structure at all scales, like a fractal.

Why pirates are better than ninjas

Sunday, January 29th, 2006

It seems the battle between pirates and ninjas rages on. But after careful reflection, I'm going to have to side with the pirates on this one. While I'm sure ninjas are extremely well trained and very good at what they do, a pirate's life is much richer and freer, and just plain more fun! Ninjas must spend so much of their lives training to perfect their ultimate fighting skills, they don't have time to really enjoy life.

Pirates understand romance. They know how a faded and torn map leading to buried treasure really inspires the imagination. I think this sense of romance comes from living in such harmony with the sea. They know the joy of an invigorating breeze of salty air. What do Ninjas know of joy? Nothing - joy would just be a distraction to them.

The piratical life is very sociable. You live in close quarters with a bunch of friends. You drink a lot (fresh water spoils fast on the open ocean so beer and rum is what there is). Ninjas don't have any sort of social lives - they trust no-one.

You know what else is great about pirates? Prosthetics! Eye patches, peg legs, hooks for hands - you name any body part and some pirate somewhere has an artifical one. Completely awesome!

And for all their talent and training, Ninjas aren't so undefeatable. They can really only win by sneaking up on people or poisoning them in their sleep. A ninja with a sword is no match for a pirate with a flintlock pistol - the pirate would just shoot the ninja dead before he got within a sword's length. And Ninjas' hovering powers? They work great in trees and on ceilings, but fail utterly over water, the natural habital of pirates.


Friday, January 27th, 2006

Why is it that one's own dreams are absolutely fascinating, but the dreams of others are generally quite dull to read? I guess dreams tend only to make sense to their owners. Looking back at my "ideas for blog posts" file, I found the following idea which I wrote down after dreaming it. At the time it seemed like a fantastic idea for a slightly surreal sci-fi story. Now it is just hilariously ridiculous:

Aliens taking the form of sticky spots invade dinner parties across Earth. Attracted to cheese sauce stains and killed by Martinis. They form geometric patterns on surfaces, as each needs to be the correct distance from its neighbours and must be next to an even number of other live aliens. So by killing or removing one alien one can cause a chain reaction leading to all but one alien disappearing. Trying to find a way to eliminate them once and for all.

Between late 1999 and early 2001 I wrote down all the dreams I could remember. In the process of writing this post I went back and re-read them all (something I haven't done since I wrote them down in the first place). Most are completely meaningless drivel like the above, but there are a few I do still remember, years later. For some of them it's just a particular colour or smell or feeling that I remember, for others it's all sorts of minute details. I wonder why some dreams I remember well and others have completely vanished from my memory. I suspect that it is something to do with how many times you recall the dream after waking, but I haven't done any experiments to verify this.

I'm just sayin'

Thursday, January 26th, 2006

Our cable modem seems to be out. I have Jerry-rigged some rudimentary internet access using some ancient technology called a "modem". It's very slow.


I'm just sayin'.

My beliefs

Wednesday, January 25th, 2006

There's a fascinating article on The Edge's World Question Center where they ask a big pile of distinguished thinkers about what they believe, but cannot prove. Curiously, right before I came across this article, I was thinking myself about things that I believe but don't have any evidence for - things that I believe simply because believing them makes me happier than not believing them. In the sense that there are some of these things, I suppose I am religious, though not in the traditional "organized religion" sense (I prefer to choose my own beliefs rather than following a pre-packaged set). For your derision I will outline these beliefs here.

I believe that I have free will, that is that there is an irreducible "something" in the universe that is "me" and that is not bound by deterministic laws of physics (i.e. that if it was simulated perfectly on a computer, no matter how much the simulation might act like me it would still not be me). I belive that quantum mechanics may leave room for this sort of dualism.

I believe that we will eventually figure out how to construct a theory of physics that includes both quantum mechanics and gravity as special cases.

I believe that true love is real - that there is more to this feeling than just a chemical reaction in the brain that has evolved to give children a better chance of survival into adulthood by providing them with stable families. (Call me a romantic.)

I also believe that I will live forever. Not in the Christian sense of living forever in heaven - I believe I will live forever in this universe. This is kind of an unusual one, so I feel I should justify it a bit (though I do not pretend for a moment that this constitutes any sort of proof). Suppose for a moment that Everett's many worlds formulation of quantum mechanics is the correct one - i.e. that whenever any fundamental particle could go either one way or another way, the entire universe is effectively "splits" into two universes identical in every respect except that this one particle goes one way in one universe and the other way in the other universe.

Now, suppose one of these choices lead inevitably to my death, while the other choice allowed me to remain alive. From my point of view, the irreducible "me" continues to exist only in one of the universes, so that is the universe that I experience. I cannot experience my own death because (by definition) I am no longer there to experience it once it is complete.

This seems to have worked pretty well so far - there have surely been lots of quantum mechanical events which, if they had turned out in a way differently than the way they did, would have lead to my death. However, that in itself is not very strong evidence since the probability of my death so far has probably been fairly low, quantum-mechanically speaking (if we discount the improbability of my conception in the first place, which I do because I wasn't alive then). Lots of people have survived to my age in my universe, and none of them quantum-mechanically needed to in my universe in the same way that I quantum-mechanically need to in my universe. However, when one day I become the oldest living human being and continue to live for much longer than anyone else has ever done, this line of thought will be more convincing.

That leads to a rather depressing-sounding scenario - I will get to watch everybody that I love die. The only way I get to die is if the universe inevitably gets to a state where no life at all is possible - if it collapses in a "Big Crunch" or expands at an ever accelerating rate leading eventually to all atoms being ripped apart. Which are also rather depressing scenarios in themselves. However, I find these possibilities significantly less depressing than the possibility of dying, so I don't worry about it too much. I'm excited to see what happens!

Believing this behooves me to support certain causes - those which will ensure I continue to be comfortable in the very long term. I want our planet to continue to be a nice place to live. I want the rest of the human race to not become extinct, so that I always have somebody around to talk to. I also want medical technology to continue to improve so that, no matter how many parts of my body start to fall of, I'll always be able to get them stuck back on or replaced so that I can continue to have a good quality of life. With this belief system these worthy causes are also in my personal interest.

Although I can't die I can still suffer a great deal of pain, so this immortality does not excuse me from having to take care not to get into a car accident, and if you say "so you think you're immortal? Prove it by shooting yourself in the head with this gun" I will refuse since the most likely outcome of accepting would be having to live with terrible brain damage.

Despite the depressing sides, this idea holds a certain comfort for me. Not having any limit on my lifespan frees me from thinking "oh I must do this before I die, and this, and this" and getting frustrated that I probably wouldn't be able to achieve them all. There are still lots of things I want to do, but there's no rush as I have plenty of time. It's kind of the opposite of the "live every day as if it was your last" philosophy.

Note that nothing in this theory mentions me by name, so anyone else can apply this theory to themselves just as I can. From your point of view, you will also experience living until the end of the universe, and experience everyone else dying. There is no contradiction here because of the many worlds interpretation of quantum mechanics - you continue to live forever in your universes, I continue to live forever in mine. You die in my universes, and I die in yours. Of course, you might not believe that this is really how things work, but if things do work like this you don't have to believe it for it to happen. Of course, this theory isn't falsifiable - if this theory turns out to be wrong you won't be able to tell me "I told you so", and if it turns out to be right I won't be able to say "I told you so" either (at least to anyone who has been born already).

While checking the links in this post, I discovered that apparently I am not the first person to have thought of this.

Sand game

Tuesday, January 24th, 2006

The falling sand game is an amusing way to while away a few hours. The physics may be distinctly non-realistic but the emergent effects caused by the different interactions between the various substances are fascinating. See if you can figure out how I generated this image:

However, the version with flammable zombies is infinitely more disturbing.

Weird soap thing

Monday, January 23rd, 2006

I found this weird soap thing in my shower. I hope it doesn't come to life and strangle me in my sleep.

Metascience: the nature of the laws governing the universe

Sunday, January 22nd, 2006

Given what we know about the laws of the universe so far, I suspect that there are not too many of them - i.e. that when we finally figure out how to unify quantum mechanics and general relativity, the resulting "theory of everything" will be conceptually quite simple - perhaps just a few lines of equations when written down in their simplest form (although they might be rather difficult to do actual calculations with).

But what if there are exceptions to these laws of physics? What if there are a finite number of points in spacetime where these equations do not hold, and events happen that are not predicted by these laws? We couldn't do science with these directly - as each of them would only happen once, any experiments around them could not be repeated. There is a great deal of evidence pointing to the existence of one such point - the one the exact moment of the big bang at the beginning of the universe.

I got this idea from thinking about the classification of the finite simple groups. I won't go into great detail about what that actually means, but a very simple introduction follows in the next paragraph for the curious.

A group is just a mathematical object consisting of a set of things and an operation (e.g. addition or multiplication, call it "*") which takes any two of these things (e.g. a and b) and generates a third thing, a*b = c. This operation must also have certain special properties: (a*b)*c = a*(b*c), an "identity" element I such that a*I = I*a = a and an inverse element a-1 for every element a such that a*a-1 = a-1*a = I. The simple groups are just groups with particular properties - kind of like the equivalent of prime numbers for groups, or the chemical elements in chemistry - they can't be broken down into smaller simple groups.

Mathematicians wished to classify the finite simple groups, to find the equivalent of the "periodic table" for them. It turned out to be a rather big job - the result is the biggest theorem in mathematics (so far), consisting of some 15,000 pages in 500 articles by 100 mathematicians over a period of 28 years. It turns out that the simple groups can be classified into 18 different families (each of which is infinitely large). However, strangely there are 26 solitary finite simple groups (called the "sporadic groups") which don't fit into any of these 18 families! The largest of these has 808,017,424,794,512,875,886,459,904,961,710,757,005,754,368,000,000,000 elements, which can be thought of as a group of rotations of some object in a space with 196,883 dimensions.

I wonder if the universe works the same way. If it does, perhaps a theory of everything could be made much simpler by including such "sporadic events". By adding a finite number of sporadic events, it might be possible to change the theory of everything from an analog of the "18 families" form to a form analogous to the definition of a finite simple group. In so doing, one could predict when and where these sporadic events occurred (or would occur). We could seek out evidence for the sporadic events predicted to have occurred in the past. For sporadic events in the future, we could go to the place they were predicted to occur at the time that they were predicted to occur and perform experiments to observe them directly and gain evidence for the simplified version of the grand unified theory. Presumably if that were to occur, any alien species who had also achieved our level of scientific knowledge would be there too. I hope that by then we would be mature enough not to go to war with them over who gets to observe it. It would be kind of like the physics version of a pilgrimage to Mecca.

This might make a rather good science fiction short story.

What science is not

Saturday, January 21st, 2006

I have recently been conversing via email with a bona fide crackpot. He initially wanted me to clear up some of his misconceptions about relativity (which I am always quite happy to do). However, this somehow lead to me agreeing to read his book in which he talks at great length about his theory which purports to unite "Western Physics" with "Eastern Metaphysics". I got to about halfway through the second chapter (which seems to consist of a number of anecdotal examples of paranormal phenomena) before I gave up due to all the inaccuracies, misunderstandings, fallacious arguments, outright lies and attacks on "the standard theory of physics". I hope my latest reply to him wasn't too rude - despite his dull book he seems to be a nice guy and I suspect there may be some interesting ideas in there if I had the patience to wade through all the pseudo-scientific rubbish.

However, this experience did get me thinking about the nature of science. Many of these crackpots seem to be under the impression that there is some kind of "scientific establishment" who spend their days in ivory towers, who have a kind of stranglehold on science, who deliberately mislead (and withhold things from) people outside "the scientific establishment", who are very closed-minded to ideas which challenge "established theory" and who often apparently have some sort of personal vendetta against the crackpots.

In reality, nothing could be further from the truth. Science is not some closed-off world inaccessible to those without a degree in it. Science is simply the process of thinking up theories, performing experiments to test those theories and then throwing away the theories that are disproved by experiment. That's all there is to it. According to this definition, we all practice science every day without even thinking about it. Whenever you think to yourself "gee, it's cold in here, I wonder if the heating's switched off" and then go and check the thermostat, you are performing science. Whenever you try the handle of your car's door after locking it to make sure it's really locked, you are performing science. That's all there is to it - no degree required and no panel of "experts" judging the worth of your theories.

Is science correct? Well, it depends what you mean by "correct". If by correct you mean "a complete and perfect theory of absolutely everything that happens in the universe", then no, it is not correct, and never can be - the results of the next experiment could always falsify the previous theories. But if by "correct" you mean "useful", then the correctness of science is undeniable - just look at all the technology we have developed as a result of the science we have done. If science wasn't a useful way of finding out about the universe and modelling it, we would never have developed these technologies and I would not be able to communicate with you like this.

So what about the phenomena that have been documented but are not explained by science, just as the power of prayer in healing, or extra-sensory perception? The trouble with these phenomena is that they are very difficult to do experiments on. Partly because of the huge number of fakers purporting to do such things for profit (in which cases the effects tend to disappear in carefully controlled, double blind experiments), and partly because such phenomena tend to require people to be involved in an active role, which makes the experiments time consuming and expensive to repeat a large number of times. You can't just set up a machine one time and then leave it running a million times to examine the effects of "the power of prayer" or "astrology", nor can you do these experiments on animals as we do for biological experiments.

This means that science applied to human beings proceeds much more slowly (and is much further behind) science applied to quarks, polymer chains or lab rats. So, when effects such as the placebo effect or the power of prayer in healing are observed, we don't have any working theories to explain such things. In time, as more experiments are done, I believe that we will have theories to explain any repeatable experimental result, but where human beings are concerned we must be patient - we can't just give up on science and say that these phenomena are unexplainable or can only be explained by invoking your preferred brand of God or aliens or flying spaghetti monsters. Of course, maybe one of those is the explanation, in which case science will determine this once all simpler theories (of which there are a lot) have been proved wrong by experiment. Thinking up theories isn't the bottleneck here, it's the experiments that are the bottleneck. A good experiment is hard to do right.

Also, scientists tend to be some of the people most open minded to new ideas. Most scientists would, I think, like nothing more than for something to be discovered that completely overturns the known laws of physics - it would make for some very exciting times and provide lots of opportunities for interesting new research.