On the cover: Cas A is the remnant of a star that exploded as a supernova in Cassiopeia about 300 years ago, seen here in radio waves. Such a violent cosmic event would have sent gravitational waves rippling along the fabric of spacetime. Scientists are now building detectors to try to catch and decode such ripples. Write for StarDate Magazine Writer's Guidelines (84K pdf -- free Adobe Acrobat software is required to view the document.)

Scientists are building a new observatory to search for these ripples. Called the Laser Interferometer Gravitational-Wave Observatory (LIGO), it will use lasers to measure tiny variations in space itself.

These ripples are called gravity waves. All moving objects generate gravity waves - like the ripples from a stone tossed into a pond. But gravity is so weak that it takes a lot of mass to create waves that are strong enough to detect. In fact, no one has ever detected a single gravity wave.

As author Christoper Wanjek explains in "Catching a Wave of Gravity," LIGO, which is scheduled to enter operation next year, and space-based detectors scheduled for launch later in the decade, could change that. Their precise instruments just may give us our first look at these tiny but ever-present ripples in the universe.