The coastline paradox is the fascinating observation that it’s not straightforward to say how long a coastline is. If you were to measure the coastline of a country by using a ruler on a globe, you would come out with a vastly different number than if you were to pace around the edge. The closer you look, the more wiggles and squiggliness you come across, and instead of converging to a more accurate length, the coastline just keeps getting longer. The smaller your ruler, the longer it gets.

This was originally spotted, incredibly, in the 1950s by an Englishman, Lewis Richardson, when trying to check a theory he had that the likelihood of war between countries depended on the length of their shared borders. Remarkably, he found that the quoted lengths of borders varied significantly. While measuring on maps at different scales, he saw that the smaller scale map he used, or the smaller the width of his callipers he measured with, the length systematically increased. When looking at coastlines, instead of borders, some countries had wigglier coasts, and so the length increased at a faster rate with the scale — for instance, Norway’s coastline, with it’s crinkly fjords, increases faster than Britain’s, which in turn increases faster than South Africa’s, as he zoomed in. The rate of this increase later became known as its fractal dimension.

Long after Richardson’s research, Benoit Mandelbrot published a paper How Long Is the Coast of Britain? Statistical Self-Similarity and Fractional Dimension that discussed how the wiggliness of something like a coastline at one scale can be repeated at smaller and smaller scales. The work led to the later term fractals. Many other things exhibit fractal-like behaviour, such as river networks, borders, brains, frequencies, lightning, and even the stock market.

There’s a super section on this in Scale, by Geoffrey West.

The difference between Great Britain, the UK and the British Isles

The coastline paradox

The Union Jack, one of the most recognizable flags in the world, is a combination of three historic flags. It represents the union of nations within the United Kingdom at the time the Union Jack flag design was created and is made up of:

The Saltire of St Andrew for Scotland: a white diagonal cross on a blue background. The term “saltire” refers to this specific diagonal cross shape in heraldry.

The Cross of St Patrick for Ireland: a red diagonal cross on a white background. Though Ireland is no longer part of the United Kingdom, it is still represented in the design.

The Cross of St George for England: a red cross on a white background.

You may notice that Wales, which is part of the United Kingdom, is not represented on the Union Jack flag. This absence is because Wales was considered a principality under the Kingdom of England, not a separate kingdom, when the flag was created.

The Union Jack we know today didn’t always look this way. The first version, known as the Union Flag of 1606, only combined the crosses of St George and St Andrew, representing England and Scotland. It wasn't until 1801, with the Act of Union between Great Britain and Ireland, that the Cross of St Patrick was added, resulting in the modern Union Flag, often referred to as the Union Jack.

The term “Union Jack” comes from naval usage. A “jack” is a flag flown from the bow of a ship. Originally referred to as the Union Flag, it became more commonly known as the Union Jack when flown at sea. Over time, this name has become standard, even on land.

According to the Flag Institute, the terms are often used interchangeably. However, some argue we should only call it a “Union Jack” when flown on a ship.

By representing the United Kingdom, the Union Jack appears on other flags. For example, the Union Jack flag is part of Australia's flag, which also includes the Southern Cross, and New Zealand's flag. It's also part of the flags of several Commonwealth countries and British Overseas Territories. It is often used symbolically to represent the UK in popular culture and events worldwide.

Sometimes, people refer to it as the Great Britain flag, though this is not technically accurate, as Great Britain refers only to the island, not the full union.

If you're interested in flags, you might already know someone studying flags is called a vexillologist. Vexillology is the study of the history, symbolism, and usage of flags. Like the history of the Union Jack here, flags are both a symbol and a product of the history and culture of a country or institution. The history and construction of the Olympic Flag is a good example.

Curious about the difference between Great Britain and the United Kingdom?

The Union Jack

This is generally the source of much confusion, even amongst those who live over here.

If you look carefully at the description of the United Kingdom (on a passport say), you’ll see it’s the "United Kingdom of Great Britain and Northern Ireland". So the UK is both of those.

Great Britain is the largest island in the British Isles and includes the three countries: England, Scotland and Wales.

The British Isles is the group of islands as a whole, including all of Ireland.

The British Isles also include several significant islands that are part of Scotland, such as the Hebrides (Inner and Outer), and the Northern Isles of both Orkney and Shetland. It also encloses the Isle of Man, which sits in the Irish Sea between England and Northern Island and is actually a self-governing British Crown Dependency with its own parliament and government.

For a little more subtlety, there's the term the British Islands (as opposed to Isles), which includes the UK, the Isle of Man and the Channel Islands, which sit closer to France.

For much further confusion, think for a moment why there’s a UK passport, Great Britain in the Olympic games, and in football, we compete as England, Wales, Scotland and N. Ireland separately. 🤔

Uk sketches