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Conway's Game of Life

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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NASA, JPL-Caltech
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Space
It's Official: Uranus Smells Like Farts
NASA, JPL-Caltech
NASA, JPL-Caltech

Poor Uranus: After years of being the butt of many schoolyard jokes, the planet's odor lives up to the unfortunate name. According to a new study by researchers at the University of Oxford and other institutions, published in the journal Nature Astronomy, the upper layer of Uranus's atmosphere consists largely of hydrogen sulfide—the same compound that gives farts their putrid stench.

Scientists have long suspected that the clouds floating over Uranus contained hydrogen sulfide, but the compound's presence wasn't confirmed until recently. Certain gases absorb infrared light from the Sun. By analyzing the infrared light patterns in the images they captured using the Gemini North telescope in Hawaii, astronomers were able to get a clearer picture of Uranus's atmospheric composition.

On top of making farts smelly, hydrogen sulfide is also responsible for giving sewers and rotten eggs their signature stink. But the gas's presence on Uranus has value beyond making scientists giggle: It could unlock secrets about the formation of the solar system. Unlike Uranus (and most likely its fellow ice giant Neptune), the gas giants Saturn and Jupiter show no evidence of hydrogen sulfide in their upper atmospheres. Instead they contain ammonia, the same toxic compound used in some heavy-duty cleaners.

"During our solar system's formation, the balance between nitrogen and sulfur (and hence ammonia and Uranus’s newly detected hydrogen sulfide) was determined by the temperature and location of planet’s formation," research team member Leigh Fletcher, of the University of Leicester, said in a press statement. In other words, the gases in Uranus's atmosphere may be able to tell us where in the solar system the planet formed before it migrated to its current spot.

From far away, Uranus's hydrogen sulfide content marks an exciting discovery, but up close it's a silent but deadly killer. In large enough concentrations, the compound is lethal to humans. But if someone were to walk on Uranus without a spacesuit, that would be the least of their problems: The -300°F temperatures and hydrogen, helium, and methane gases at ground level would be instantly fatal.

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Live Smarter
Feeling Anxious? Just a Few Minutes of Meditation Might Help
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iStock

Some say mindfulness meditation can cure anything. It might make you more compassionate. It can fix your procrastination habit. It could ward off germs and improve health. And it may boost your mental health and reduce stress, anxiety, depression, and pain.

New research suggests that for people with anxiety, mindfulness meditation programs could be beneficial after just one session. According to Michigan Technological University physiologist John Durocher, who presented his work during the annual Experimental Biology meeting in San Diego, California on April 23, meditation may be able to reduce the toll anxiety takes on the heart in just one session.

As part of the study, Durocher and his colleagues asked 14 adults with mild to moderate anxiety to participate in an hour-long guided meditation session that encouraged them to focus on their breathing and awareness of their thoughts.

The week before the meditation session, the researchers had measured the participants' cardiovascular health (through data like heart rate and the blood pressure in the aorta). They evaluated those same markers immediately after the session ended, and again an hour later. They also asked the participants how anxious they felt afterward.

Other studies have looked at the benefits of mindfulness after extended periods, but this one suggests that the effects are immediate. The participants showed significant reduction in anxiety after the single session, an effect that lasted up to a week afterward. The session also reduced stress on their arteries. Mindfulness meditation "could help to reduce stress on organs like the brain and kidneys and help prevent conditions such as high blood pressure," Durocher said in a press statement, helping protect the heart against the negative effects of chronic anxiety.

But other researchers have had a more cautious outlook on mindfulness research in general, and especially on studies as small as this one. In a 2017 article in the journal Perspectives on Psychological Science, a group of 15 different experts warned that mindfulness studies aren't always trustworthy. "Misinformation and poor methodology associated with past studies of mindfulness may lead public consumers to be harmed, misled, and disappointed," they wrote.

But one of the reasons that mindfulness can be so easy to hype is that it is such a low-investment, low-risk treatment. Much like dentists still recommend flossing even though there are few studies demonstrating its effectiveness against gum disease, it’s easy to tell people to meditate. It might work, but if it doesn't, it probably won't hurt you. (It should be said that in rare cases, some people do report having very negative experiences with meditation.) Even if studies have yet to show that it can definitively cure whatever ails you, sitting down and clearing your head for a few minutes probably won't hurt.

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