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The Godzilla of Solar Ovens

Built in 1949, the giant Mont-Louis solar furnace could instantly ignite wood and melt through a steel plate in seconds

2 min read
Photo showing a 1-megawatt solar furnace in Odeillo.
The double-mirror solar furnace in Mont-Louis, France.
Photo: Manuel Litran/Paris Match/Getty Images

Constructed in 1949 in the citadel of Mont-Louis in the French Pyrenees, this double-mirror solar furnace [PDF] concentrated the sun’s rays to melt just about anything that wandered into its 3,000 °C beam. Engineer Félix Trombe [shown below] designed the solar furnace and used it for high-temperature experiments on materials and to demonstrate how to fire ceramics without using wood.

In 1975 the solar furnace was removed from the center of the citadel to a spot near the city walls, where it continues to be used for educational purposes. On a sunny day, the furnace can concentrate 50 kilowatts of solar energy into an area of just a few square centimeters. This is enough focused radiation to instantly ignite wood or liquefy a steel plate in a matter of seconds:

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How the Graphical User Interface Was Invented

Three decades of UI research came together in the mice, windows, and icons used today

18 min read
Stylized drawing of a desktop computer with mouse and keyboard, on the screen are windows, Icons, and menus
Getty Images/IEEE Spectrum

Mice, windows, icons, and menus: these are the ingredients of computer interfaces designed to be easy to grasp, simplicity itself to use, and straightforward to describe. The mouse is a pointer. Windows divide up the screen. Icons symbolize application programs and data. Menus list choices of action.

But the development of today’s graphical user interface was anything but simple. It took some 30 years of effort by engineers and computer scientists in universities, government laboratories, and corporate research groups, piggybacking on each other’s work, trying new ideas, repeating each other’s mistakes.

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