9 July: Call of the Horizon Day

9 July is Call of the Horizon Day. 10 things you didn’t know about horizons.

1. The horizon is usually defined as the line that separates the Earth from the Sky. However, the word is also commonly used in geology, to describe a line separating two layers of soil or rock.
2. The word horizon derives from the Greek word orizein, which means to limit, or to separate.
3. The true horizon is a theoretical horizontal line, actually a circle with the observer in the centre. Usually the true horizon can’t be seen because hills, mountains, buildings, trees etc are in the way. The only time you can see it is when looking at the sea.
4. How far away is the horizon? It’s a bit like asking how long is a piece of string, because how far away the visible horizon is depends to a great extent on the weather conditions and how high up the observer is. There are complicated mathematical formulae to work it out, which I won’t try to go into here. That said, for a human being whose eyes are 1.70 metres (5 ft 7 in) above the ground, standing at sea level in standard atmospheric conditions, the horizon is about 5 kilometres (3.1 mi) away.
5. On other planets the horizon will be a different distance away from you depending on the radius of the planet. On Mars, for example, the horizon is 73% as far away as it would be on Earth, and on the Moon it’s 52% as far away.
6. Go high enough up and the horizon becomes a slight curve (the curvature of the Earth). Go into orbit and the theoretical circle becomes an ellipse, because the Earth is not a perfect sphere.
7. Which brings us to flat Earthers. People living before the Middle Ages, and some opinionated people alive today interpret the horizon as the edge of the Earth which you’d fall off of should you ever reach it. Strangely, no-one ever did. However, observing the horizon helped prove that the Earth was a sphere. Aristotle noticed that the further south he went, the higher some constellations rose from the horizon. The shape of the Earth also explains why, if a tall building is far enough away on a distant shore, you can’t see the bottom of it.
8. When describing the position of the Earth relative to the rest of the sky astronomers use a concept called the celestial or astronomical horizon, an imaginary horizontal plane always at a 90-degree angle from the observer's zenith (the point directly above them).
9. Before we invented Radio and satellite navigation, the horizon was extremely important for navigation and communication. You could only communicate with another ship if you could actually see it, and the position of the Sun and stars relative to the horizon helped early sailors work out where they were, what time it was and which direction they were travelling in.
10. There’s a word for the part of the sea closest to the horizon. It’s called the offing. Hence the expression that something is “in the offing”.

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Killing Me Softly

Sebastian Garrett is an assassin. It wasn’t his first choice of vocation, but nonetheless, he’s good at it, and can be relied upon to get the job done. He’s on top of his game.

Until he is contracted to kill Princess Helena of Galorvia. She is not just any princess. Sebastian doesn’t bargain on his intended victim being a super-heroine who gives as good as she gets. Only his own genetic variant power saves him from becoming the victim, instead of Helena. 

Fate has another surprise in store. Sebastian was not expecting to fall in love with her.

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