thegreenjournal.ca | 2008 June 22

Quality, Affordable Child Care?

Source: Canadian Centre for Policy Alternatives ⋅ June 22, 2008 ⋅

The GHG Spot: North Pole May Be Ice Free for First Time This Summer

Source: Checkerspot Magazine ⋅ June 22, 2008 ⋅

Arctic warming has become so dramatic that the North Pole may melt this summer…>

Put oil firm chiefs on trial, says leading climate change scientist

Source: Stephen Rees's blog ⋅ June 22, 2008 ⋅

The Guardian
James Hansen, one of the world’s leading climate scientists, will today call for the chief executives of large fossil fuel companies to be put on trial for high crimes against humanity and nature, accusing them of actively spreading doubt about global warming in the same way that tobacco companies blurred the links between smoking [...]

Rubik’s Cube Inspired Puzzles Demonstrate Math’s “Simple Groups” [Scientific American Magazine]

Source: Scientific American Topic - Green Technology ⋅ June 22, 2008 ⋅

Editor’s Note: The online puzzles mentioned in the July magazine can be found here.

Millions of people have been perplexed at one time or another by Rubik’s Cube, a fascinating puzzle that took the world by storm in the 1980s. If you somehow missed the puzzle–or the 1980s–the cube is a plastic gizmo that appears to be made up of 27 small cubes, or “cubies,” stacked into a larger cube, three cubies to an edge. Each of the six square faces of the larger cube is colored in one of six eye-catching colors–typically blue, green, orange, red, yellow or white. We said the cube appears to be a stack of cubies, but appearances here are deceptive. An ingenious mechanism, invented in 1974 by a Hungarian teacher named Erno Rubik (and, independently, in 1976 by a Japanese engineer named Terutoshi Ishige), enables any of the six square faces of the large cube to be twisted about the center of that face. Twist the faces in some random sequence five or six times, and you have a cube so scrambled that only an expert–a cubemeister–can restore order. The object of the puzzle is to put an arbitrarily scrambled cube back into its original state, one solid color per face, thereby “solving” the cube.

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How to Solve the Rubik’s Cube [Features]

Source: Scientific American Topic - Green Technology ⋅ June 22, 2008 ⋅

This story is a supplement to the feature "Rubik’s Cube Inspired Puzzles Demonstrate Math’s "Simple Groups"" which was printed in the July 2008 issue of Scientific American.

Solving the authors’ new puzzles builds on techniques developed for the study of mathematical entities called groups. One essential technique from group theory is specifying a simple, unambiguous system for writing down the elements of the group and how they combine.

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