Standard and Daylight-Saving Time
The four standard-time zones of the U.S. are the result of a long effort to achieve a compromise among competing demands. Congress is still confronted with the task of doing the same for daylight-saving time...
Features
Carbon Monoxide in the Galaxy
Radio telescopes tuned to the characteristic emission wavelength of carbon monoxide molecules reveal the presence of a vast ring of cold, star-forming clouds in the invisible inner reaches of the M1lky Way...
The Spin of the Proton
When two protons collide, the outcome depends on which way the particles are spinning. The effect seen in violent collisions suggests there are objects in the proton that spin very rapidly...
The Molecular Basis of Cell Movement
Not only muscle cells but also other cells are capable of movement, from creeping over a surface to the internal streaming of cytoplasm. All these movements are engineered by a small number of proteins...
Laser Chemistry
Most chemical reactions must be initiated by an input of energy. A laser can often supply energy at the precise frequency needed to drive the reactants down the most favored chemical pathway...
A Brain-Cooling System in Mammals
Carnivorous mammals and some of their mammalian prey endure lethal extremes of heat and exertion because they have a rete, or heat-exchange network, that keeps the brain from getting too hot...
Intrinsically Difficult Problems
Some kinds of computational problems require for their solution a computer as large as the universe running for at least as long as the age of the universe. They are nonetheless solvable in principle...
Giotto's Portrait of Halley's Comet
A blazing comet represents the star of Bethlehem in one of Giotto's famous Arena Chapel frescoes in Padua. It is a naturalistic portrait of Halley's Comet as seen during its spectacular apparition of 1301...
Departments
50 and 100 Years Ago, May 1979
Science and the Citizen
- Letters
Letters to the Editors, May 1979
- Recommended
Books, May 1979
- Mathematical Recreation
Mathematical Games, May 1979
- Amateur Scientist
The Amateur Scientist, May 1979
- Departments
The Authors, May 1979
Bibliography, May 1979
