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We hope those of you in the Northern Hemisphere are enjoying a glorious summer. This month we’re thinking about the sun, naturally, and its effect on how and when we sleep. These highlights from the Scientific American archives also include some fun history of bridges, which you might be crossing more of during the summer (and waning pandemic) travel season. We hope you enjoy the journey.


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Laura Helmuth, Editor in Chief

The Sun

The Sun

An early device for converting the sun’s energy into steam power. (February 1884)

February 1884:

We’ve tried to harness the biggest energy source in our solar system since the early days of powered machines.

October 1915:

Calculating the level of solar radiation in space, before the advent of rockets, required some ingenuity.

February 1990:

The sun’s output is slightly variable over different timescales. Satellites and Earth measurements are trying to quantify it.

Sleep: It’s Important

Sleeping brain

The sleeping brain is an active organ. October 2015.

May 1878:

In this old article, lack of sleep causes “softening of the brain, insanity, and death.” Funny! Except that psychosis and death are both possible.

November 2003:

Why did evolution design us to sleep? Isn’t it a waste of time? Here the enigma starts getting unravelled.

October 2015:

Mental deficits from lack of shut-eye show the neurological benefits of sleep.


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Bridges:Human Ingenuity


Bridge of braided willow serves travellers across a mountain stream. (May 1892)

May 1892:

A description of a rope bridge built by a community in Kashmir, India.

November 1932:

Concrete makes a graceful and still-standing bridge near Pittsburgh.

December 1997:

The Akashi-Kaikyo bridge, still the longest suspension bridge in the world, links islands in Japan.

Current Issue: July 2021
June Issue: The Coronavirus Pandemic

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For more highlights from the archives, you can read July's 50, 100 & 150 Years Ago column.


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