I have three points to cover this week. This isn’t funny, I just want to cover a few points in case any of it’s useful material.
First point, in most pirate films, you see someone on a ship looking at the horizon with a triangle-shaped instrument with an arc at the bottom, made out of metal with a little telescope on the side of it. It’s called a sextant.
You can use it to measure the height of celestial object above the horizon, and if you do that at a known time, you can determine your latitude. Imagine the sun. If you’re at the equator then at noon the sun will be directly overhead. And the further north or south you are, the lower the maximum height the sun reaches above the horizon each day. Measure the maximum angle during the day, and you’ll know how north or south you are. A sextant has filters to stop you damaging your eyes when you look at the sun. I hope that’s clear.
You can also use it to find out your longitude, and that’s because a celestial body such as the moon travels through the sky at a known speed. Say you pick the North Star, and at midnight you measure the angle between the moon and the North Star, then if you know what that angle would be if you were in Greenwich at midnight, then based on the difference between that and the angle where you actually are, you’ll know what the local time is. If you know the difference between the angles - and therefore the times - where you are, and in Greenwich - so in other words you know your time difference from GMT - then you know how far round the earth you are.
You can also use the sextant to measure the angle between the horizon and the top of a landmark, and if you know how far you are from the landmark, you’ll know how tall it is. Also if you know how tall it is already, you can find out how far away it is. In case you didn’t know.
If you know where you are, and you turn a sextant sideways, and measure the angle between a landmark whose location you know and a landmark whose location you don’t know, you can find out the unknown position of the other landmark. That’s because if you know the position of two corners, then you know the length of one of the sides of a triangle; and if you know the size of one of the angles adjacent to that side, then you can use maths to find out the position of the third corner.
My second point is that one of the massive towers near Liverpool Street is made of shiny steel and glass, and at the foot of the skyscraper there’s a stone plaza with a cafe. In that plaza there are the enormous feet of enormous buttresses that stretch very high up to the side of the building. They’re huge - and they each have an enormous steel bolt through them at the base that makes them look like machinery or the feet of a giant robot animal. Not a spider because the buttresses are not really scary but maybe one of the friendlier lizards, like a chameleon. So also in that plaza, there are flower bed islands, with seating round them, and growing from the middle of the islands there were big swaying bunches of giant bamboo, probably twenty feet tall. I remember this from when I used to visit the bamboo before, when Croud was based on Worship Street. If you’re quiet, you’ll hear that giant bamboo makes a creaking sound. I love the combination of steel & glass, and the swaying trunks of giant bamboo and their leafy green leaves, but I realised today, it’s missing, and it’s been cut down. The bamboo now is just bunches of four-foot dead stumps, and I don’t know when it happened or who to ask about it. I looked at the people around there wearing high viz vests, but I don’t think they’ll help me.
The third point: today is the second of February, and that’s the day that’s repeated in the acclaimed 1993 film, Groundhog Day. I haven’t seen it, I plan to, but anyway as I think everyone knows, the film is about a man who gets stuck in a time loop and has to keep reliving the same day over and over again. The film was commended by religious groups because some people see it as an allegory for reincarnation. I know it’s less cool than the sextant, but I’m beginning to find ChatGPT useful so I asked it, “if I thought I could remember a past life, would that be proof that reincarnation is impossible,” and it just kept saying “An error occurred. If this issue persists please contact us through our help center” over and over again. I don’t know why.
That’s all I wanted to cover.
Have a good weekend.