Table of Contents

The Chlorine Threat to Stratospheric Ozone
by Joe W. Waters
From JPL's satellite-borne microwave instrument, launched in 1991, has come dramatic additional evidence implicating chlorine chemistry in Antarctica's ozone hole—and the suggestion that similar processes of ozone destruction are occurring in the north.

New Light on the Nature of Darkness
by H. Jeff Kimble
In the bizarre world of quantum optics, it's possible to make light that is darker than ordinary darkness, and othet even stranger things.

Roundworm Cells and Cancer Genes
by Paul W. Sternberg
By studying a creature the size of this comma, biologists may be closing in on the secrets of the human body's cancer-causing genes.

The Bad News Bearings
by Douglas L. Smith
How do you get to something hidden behind 14½ tons of glass on one side and 20 tons of steel on the other, without separating the two? Such was the Palomar Observatory staff's dilemma when bearings deep within the Hale Telescope's 200-inch mirror began to stick.



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