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Laser Weapons

Could orbiting lasers defend a nation against missile attack? The technological obstacles are insurmountable; furthermore, such weapons would be vulnerable to simple countermeasures

By Kosta Tsipis

Magnetic Navigation in Bacteria

Certain aquatic bacteria are magnetotactic: they have tiny internal compasses that orient them in the earth's magnetic field. Swimming along the inclined magnetic field lines directs them toward the mud...

By Richard B. Frankel and Richard P. Blakemore

The Recumbent Stone Circles of Scotland

These megalithic monuments, like many others, have been seen as ancient astronomical observatories. It seems clear that although they are astronomically aligned, their purpose was purely ritual...

By Aubrey Burl

Jupiter and Saturn

Competing models seek to describe the sun's two giant companions. In one model the winds are confined to a thin layer at the surface; in another the winds extend through the fluid depths of each planet...

By Andrew P. Ingersoll

The Hearing of the Barn Owl

The bird exploits diikrences between the sound in its left and right ears to find mice in the dark. It can localize sounds more accurately than any other species that has been tested

By Eric I. Knudsen

Fibrinogen and Fibrin

The plasma protein fibrinogen is converted into fibrin to form a blood clot. In time the clot breaks down. Both processes can now be understood in terms of the detailed structure of the protein...

By Russell F. Doolittle

Computer Algebra

Symbols as well as numbers can be manipulated by a computer. New, general-purpose algorithms can undertake a wide variety of routine mathematical work and solve intractable problems

By Richard Pavelle, Michael Rothstein and John Fitch

The Anthropic Principle

Certain conditions, such as temperature, were favorable to the emergence of life on the earth. The anthropic principle argues the reverse: the presence of life may "explain" the conditions...

By George Gale


  • 50 and 100 Years Ago: December 1981

  • Science and the Citizen, December 1981

  • Letters

    Letters to the Editors, December 1981

  • Recommended

    Books, December 1981

  • Mathematical Recreation

    Mathematical Games, December 1981

  • Amateur Scientist

    The Amateur Scientist, December 1981

  • Departments

    The Authors, December 1981

  • Annual Index 1981

  • Bibliography, December 1981

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