
                         Roanoke Times
                 Copyright (c) 1995, Landmark Communications, Inc.

DATE: THURSDAY, May 27, 1993                   TAG: 9305270173
SECTION: NATIONAL/INTERNATIONAL                    PAGE: A8   EDITION: METRO 
SOURCE: Associated Press
DATELINE: PASADENA, CALIF.                                LENGTH: Short

SATELLITE PROBE FINDS EDGE OF SOLAR SYSTEM

The twin Voyager space probes have found the first direct evidence for the existence of the true edge of the solar system, where solar wind hits interstellar space, NASA said Wednesday.

While many people wrongly believe the solar system ends with the outermost planet, scientists say its true edge is called the "heliopause," a place where solar wind - electrically charged particles spewed by the sun - collides with similar particles in interstellar space.

That collision produces intense, low-frequency radio signals that were detected by antennas on the Voyager 1 and 2 spacecraft starting in August, said University of Iowa physicist Don Gurnett, a member of the Voyager science team.

Gurnett announced the discovery Wednesday during the American Geophysical Union's spring meeting in Baltimore.

The exact location of the edge of the solar system "remains one of the great unanswered questions in space physics," although the new discovery narrows its possible location, NASA said.

It probably is located 90 to 120 times further from the sun than Earth, said Ralph McNutt, a Voyager researcher at Johns Hopkins University.

by CNB