Thursday, April 26, 2012

On Those Somewhat Serious Tones

I've always found that I tend to take on a most seriously formal tone in my mind when proof reading my writing, even when my tone was very relaxed and casual when my mind was dictating to my hands what to write. I recently bought myself a cheap headset and have started recording my voice, and to my surprise, I found that the relaxed and casual voice that is constantly echoing inside my head comes out as slightly boring and monotonous - essentially the same as my mental proof reading voice.

I've always liked the sound of my own voice. Not in the figure-of-speech sense that would imply that I talk a lot (although I can, if you get me started, but that's more because my mind just starts throwing things at me, and my mouth just has to do its best to keep up). It actually came as quite a shock to me to hear my recorded voice (which is very different to hearing your voice over speakers while you are speaking).

My mind works incredibly slowly. I like to think it's because it's an incredibly complex machine that has far too many intricate parts, so it takes a while for them to all come together and give me a final thought, but really, that's just another way of saying my mind is easily distracted. Anyway, the net effect of this is that my voice sounds much slower when I speak out loud than when I say it in my head, even though they seem to take the same length of time to say. It may sound contradictory, but if you were in my head, you'd know what I mean (obviously).

(On a side note: I'm eating my mother's chicken curry while writing this - easily one of my favourite dishes of all time. Her secret ingredient is apples, which practically disintegrate into the creamy sauce to sweeten it up and balance the flavours. It's just hot enough to tingle on your lips and leave a comforting glow down the back of your throat for a few minutes after eating it, but not so hot that you break into a sweat. And the uniform yellow colour means that I can eat it in what ever order I like, as long as I pick out the chunks of chicken first.)

(On another side note: I'm not sure why, but my thoughts have been very incoherent recently. I really struggle to pick one thought at a time from the hundreds my subconsciousness throws forward. Incidentally, this started shortly after I started my current box of Omega 3 supplements. They are now yellow capsules (they used to be red), have different ingredients, and come in different packaging. I am starting to doubt that they are even the same thing. If only I was more fond of sea food.)

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Tuesday, April 17, 2012

On the Sizes of Things in the Sky

This post was undoubtedly and unashamedly inspired by a certain post at The Oatmeal. In a recent comic, Inman wrote "Write a post explaining why the sun and moon appear to be the same size in the sky." And so I did.

The truth is that we don't actually see sizes and distances. Each eye picks up a flat, two dimensional projection of the world. Our brain then calculates a couple of angles (or actually retrieves them from a database of interconnected neurons that carefully and automatically arranged themselves to match the outside world during your very early childhood), and you interpret these angles in three dimensions to give distances, instinctively using the distance between your two eyes as a reference.

So, on to the sun and the moon. At any time, the distance from you to the sun is somewhere between 147 and 152 million km, and the sun is just under 1.4 million km across. However, our eyes only see this as an angle. Using elementary trig, this means that we see the size of the sun as an angle of between 0.52 and 0.54°.

The distance to the moon varies a lot more. It could be anywhere from 362 to 405 thousand km away from the Earth, but it's only about 3470 km across, so our eyes see the size of the moon as an angle between 0.49 and 0.55°. In other words, it's about the same angle as the sun.

The reason the angles are similar is that, entirely by coincidence, the ratio of the distance to radius of the sun (at 150 million to 1.4 million) and same ratio for the moon (384 thousand to 3.47 thousand) turn out to be remarkably close together (110 and 108). Because the Earth has an elliptical orbit around the sun and the moon has an elliptical orbit around the Earth, the moon can appear anywhere from 9.3% smaller to 4.8% larger than the sun.

But, since the moon is almost 400 times closer to us than the sun, shouldn't our brains be able to tell us that the sun must be 400 times larger than the moon? Most people's brains (not mine though) are pretty good at judging distances. Millions of years ago, when our distant ancestors were apes climbing in trees, they needed to be able to tell where the next branch to grab onto was, or risk falling to their death. So, evolution placed our two eyes on the fronts of our heads a fixed distance apart, and gave our brains the ability to interpret the subtle differences in the angles that our two eyes see as distances. That is how I know (ignoring my common sense) that the car outside my office window (which appears an 8.6° angle to my eyes) is much larger than my computer mouse (which appears as a 10.4° angle), despite the fact that I can cover the car completely with my mouse (which can in turn be covered by my pinky finger next to my eye).

The catch is that, as the objects get further away, the differences in the angles our eyes perceive also gets smaller at a ridiculous rate. For example, my eyes happen to be roughly 7 cm apart, so the difference in the position of my computer mouse between my two eyes is a whopping 8°, yet for the car outside, it is only a tenth of a degree. That's how my brain knows that the car is almost 100 times further from me than the mouse. Our brains work well with differences of tenths of a degree. They can even deal with hundredths of a degree to a certain extent, but when they get into thousandths of a degree (the sort of angles you get from distant mountains), they start going wobbly. Anyone who's been hiking in an open flat environment can tell you that it's impossible to tell if a hill is two kilometres away or ten. When we look at the moon, the difference in the moon's position over that distance works out to just over a millionth of a degree, and for the sun, it's just a few billionths. Our brains have no hope of perceiving such small angles. (Just for interest, the difference in angles for the brightest star in the sky, Sirius, is less than 5 millionths of a trillionth of a degree.)

So, in short, the sun and moon are the same size for exactly the same reason that you can pretend to squash other people with your thumb, or take photos of some idiot pretending to hold up the Leaning Tower of Pisa.

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Thursday, April 12, 2012

On Collared Shirts

I just do not understand the appeal of collared shirts. I don't even understand why they are considered more formal than T-shirts. In fact, I don't really get what makes anything formal, but that's beside the point. The only possible advantage that I can see for a collared shirt is that it can be taken off without having to remove one's hat. However, I don't really see why anyone would really care about that (perhaps with the exception of strippers, of course). I really prefer comfort over anything else. That is why my casual outfit consists of jeans and a T-shirt, and my formal wear consists of newer jeans and a slightly neater T-shirt.

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Wednesday, April 4, 2012

On the construction of a Boeing 747 in Minecraft - Part I

Over a year ago, I began playing Minecraft. One of the first things I started building was a scale model of a Boeing 747. One thing led to another, and after a couple of weeks of working on it, I moved on and dropped the project. A couple of months ago, I started playing Minecraft on a multiplayer server, and from the start, I wanted to start the project over, doing it properly this time. And so I did. With slightly less time to spend on it than I'd like (I hate that I enjoy sleep too much to give it up), it is going to take me a while to finish, but I am determined to finish it this time. So, my next big Minecraft project is a scale model of a South African Airways Boeing 747-400 (as shown below) that is roughly twice the size of the real thing.

Because of the discrete nature of distance measurement in Minecraft, I have taken some artistic license and added or removed a block or two in order to get it to match the look of the actual aircraft. For example, while the actual aircraft is 70.6 m long, I have made my model 143 blocks long in order to balance the distances between features more easily. Likewise, the fuselage is one block too narrow in order to keep the symmetry of the landing gear.

I tried something new here. I got myself a headset a while ago and decided to put it to use. I spent about two days working out how to record video with voice commentary in Linux (Fraps is the easy solution, but it only works in Windows). Eventually, I got it working, and so here is the first video I have recorded. I apologise in advance for the sloppy editing, recording, and encoding. Any suggestions are not only welcomed, but are probably necessary.

(On a side note: In the opening and closing sections of the video, my voice sounds particularly nasal. This is because of the smell emanating from the ceiling from what was apparently the rotting corpse of a dead rat (We never did find the body). The middle portion of the video was re-recorded later due to technical difficulties, and my voice is unusually hoarse due to the air freshener sprayed to mask the stink of the rat. Anyway, the presence of rats in the roof is one of the clearest indicators that autumn is here.)

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