Feature

Front Matter

Colleges Can Handle GI’s

Over 400 Astronomers See Vatican Observatory

Porpoises May Have Their Own Sonar Device

Gum Disease Curable, Preventing Loss of Teeth

Spectral Lines Measured

[Photograph]: Ripple Tank

Helium Burned to Carbon for Older Stars’ Energy

Problems of Space Travel

Belly Landing Makes Runways Obsolete

Snails and Tortoise Not Lazy but Muscles Slow

Football-Sized Core