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Conway's Game of Life

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In 1970, mathematician John Horton Conway invented a game called Life. Conway was intrigued by John von Neumann's theories about self-replicating automata: simple mathematical formulae representing virtual "life forms" that could be depicted in a virtual world. Of course, in von Neumann's day the "virtual world" was a piece of graph paper with some squares filled in (squares being the life forms), but still, it was a pretty cool idea. Conway took von Neumann's ideas a step further, creating a computer simulation of the graph paper-based automata, and forcing the automata to follow simple rules:

The universe of the Game of Life is an infinite two-dimensional orthogonal grid of square cells, each of which is in one of two possible states, live or dead. Every cell interacts with its eight neighbours, which are the cells that are directly horizontally, vertically, or diagonally adjacent. At each step in time, the following transitions occur:

1. Any live cell with fewer than two live neighbours dies, as if by needs caused by underpopulation.
2. Any live cell with more than three live neighbours dies, as if by overcrowding.
3. Any live cell with two or three live neighbours lives, unchanged, to the next generation.
4. Any tile with exactly three live neighbours cells will be populated with a living cell.

The initial pattern constitutes the 'seed' of the system. The first generation is created by applying the above rules simultaneously to every cell in the seed — births and deaths happen simultaneously, and the discrete moment at which this happens is sometimes called a tick. (In other words, each generation is a pure function of the one before.) The rules continue to be applied repeatedly to create further generations.

Conway's Game of Life often starts with a very simple playing field: mostly blank, with a few little bits filled in. What's fascinating is how complexity arises from the simple rules above, as they operate on the seed (the initial condition of the game). Some crazy things happen, including "guns" (pictured above), in which base cells seem to shoot virtual pellets. (When Bill Gosper at MIT discovered/invented guns, he won a $50 prize from Conway.)

Since 1970, Conway's Game of Life has been implemented on virtually every computer platform, either as a time waster or a nice way to get started with simple graphics programming. You can even get Life on the iPhone. To get a feel for Life, try playing The irRegular Game of Life, a nice Flash game in which you solve puzzles by creating automata (you do have to sit through an ad first, though). For a more traditional version of Life, check out this Java version (warning: kinda slow). To learn more about Conway's famous game, read up at Wikipedia.

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science
Why a Howling Wind Sounds So Spooky, According to Science
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Halloween is swiftly approaching, meaning you'll likely soon hear creepy soundtracks—replete with screams, clanking chains, and howling winds—blaring from haunted houses and home displays. While the sound of human suffering is frightful for obvious reasons, what is it, exactly, about a brisk fall gust that sends shivers up our spines? In horror movie scenes and ghost stories, these spooky gales are always presented as blowing through dead trees. Do bare branches actually make the natural wailing noises louder, or is this detail added simply for atmospheric purposes?

As the SciShow's Hank Green explains in the video below, wind howls because it curves around obstacles like trees or buildings. When fast-moving air goes around, say, a tree, it splits up as it whips past, before coming back together on the other side. Due to factors such as natural randomness, air speed, and the tree's surface, one side's wind is going to be slightly stronger when the two currents rejoin, pushing the other side's gust out of the way. The two continue to interact back-and-forth in what could be likened to an invisible wrestling match, as high-pressure airwaves and whirlpools mix together and vibrate the air. If the wind is fast enough, this phenomenon will produce the eerie noise we've all come to recognize in horror films.

Leafy trees "will absorb some of the vibrations in the air and dull the sound, but without leaves—like if it's the middle of the winter or the entire forest is dead—the howling will travel a lot farther," Green explains. That's why a dead forest on a windy night sounds so much like the undead.

Learn more by watching SciShow's video below.

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Space
SpaceX's Landing Blooper Reel Shows That Even Rocket Scientists Make Mistakes
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SpaceX's Falcon 9 rocket launches.
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On March 30, 2017, SpaceX did something no space program had done before: They relaunched an orbital class rocket from Earth that had successfully achieved lift-off just a year earlier. It wasn't the first time Elon Musk's company broke new ground: In December 2015, it nailed the landing on a reusable rocket—the first time that had been done—and five months later landed a rocket on a droneship in the middle of the ocean, which was also unprecedented. These feats marked significant moments in the history of space travel, but they were just a few of the steps in the long, messy journey to achieve them. In SpaceX's new blooper reel, spotted by Ars Technica, you can see just some of the many failures the company has had along the way.

The video demonstrates that failure is an important part of the scientific process. Of course when the science you're working in deals with launching and landing rockets, failure can be a lot more dramatic than it is in a lab. SpaceX has filmed their rockets blowing up in the air, disintegrating in the ocean, and smashing against landing pads, often because of something small like a radar glitch or lack of propellant.

While explosions—or "rapid unscheduled disassemblies," as the video calls them—are never ideal, some are preferable to others. The Falcon 9 explosion that shook buildings for miles last year, for instance, ended up destroying the $200 million Facebook satellite onboard. But even costly hiccups such as that one are important to future successes. As Musk once said, "If things are not failing, you are not innovating enough."

You can watch the fiery compilation below.

[h/t Ars Technica]

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