<== This is a picture from the interactive geometry package Cinderella showing the behavior of 10,000 starting values in the rectangle [0,1]x[h-1,h+1], where h is the height of the horizontal line, after six iterations of the algorithm which reflects a point x in the sphere then reflects the outcome in the line and then averages the result y with x. It is an accessible prototype for a remarkable image reconstruction algorithm known variously as Douglas-Ratchford, Lion-Mercier, Fienup's method, and "divide-and-concur." Some related graphics can be generated and displayed at these URLs: Expansion Reflection (wait 30-60 seconds to see the display).

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So the Internet causes scientific knowledge to become obsolete faster than was the case with the older print media. A scientist trained in the print media tradition is aware that there is knowledge stored in the print journals, but I wonder if the new generation of scientists, who grow up with the Internet, are aware of this. Also, print journals were forever. They may have merely gathered dust for decades, but they could still be read by any later generation. I can no longer read my own articles stored on the floppy discs of the 1980's. Computer technology has changed too much. Will information stored on the Internet become unreadable to later generations because of data storage changes, and the knowledge lost? -- Frank J. Tipler, "Will the Great Leveler Destroy Diversity of Thought?", 8 Jan 2010, available at Online article.

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