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
Features
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...
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...
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...
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
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...
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
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...
Departments
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
