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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

By Elizabeth Harrison and Ian R. Bartky

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

By M. A. Gordon and W. B. Burton

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

By Alan D. Krisch

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

By Elias Lazarides and Jean Paul Revel

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

By Avigdor M. Ronn

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

By Mary Ann Baker

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

By Ashok K. Chandra and Larry J. Stockmeyer

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

By Roberta J. M. Olson

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

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May 1979

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