From NASANews@luna.osf.hq.nasa.govWed Nov 8 13:14:11 1995 Date: Mon, 6 Nov 1995 16:19:25 -0500 From: NASA HQ Public Affairs Office To: press-release-com@mercury.hq.nasa.gov Subject: Space Disturbance Detected by NASA Satellite before Reaching Earth Don Savage Headquarters, Washington, DC November 6, 1995 (Phone: 202/358-1547) Jim Sahli Goddard Space Flight Center, Greenbelt, MD (Phone: 301/286-0697) RELEASE: 95-202 SPACE DISTURBANCE DETECTED BY NASA SATELLITE BEFORE REACHING EARTH A NASA spacecraft detected a huge interplanetary disturbance which struck the Earth's protective magnetic field on Oct. 18, producing a magnetic storm and auroral displays, or "Northern Lights" that persisted for two days. The phenomenon was visible in the United States as far south as Denver, according to scientists at NASA's Goddard Space Flight Center, Greenbelt, MD, who reported critical satellite data to other government agencies and scientists around the world. The information was relayed electronically to the U.S. Air Force and to the National Oceanic and Atmospheric Administration's Space Environment Laboratory, in Boulder, CO, where evaluators issued an updated "space weather alert" to commercial satellite operators, electrical utilities and other organizations worldwide. "The rapid response to the Wind observations and the prompt issuance of the alert were made possible by advanced data systems, technology and networks," said Dr. Keith Ogilvie of Goddard, NASA's Project Scientist for Wind. The central processing and distribution systems were developed and implemented by NASA and supported by the Wind science teams, NOAA, the Air Force, and international partners. The disturbance, called a "giant magnetic cloud," was 65 million miles across and speeding toward the Earth at over 2.1 million miles per hour when it was detected at 3 p.m. EST on Oct. 18 by NASA's Wind spacecraft. Wind is an unmanned spacecraft patrolling interplanetary space 662,000 miles from Earth, pointed toward the Sun. Invisible to normal telescopes and to the human eye, the cloud was composed of magnetic fields and electrified subatomic particles ejected from the outer atmosphere or corona of the Sun. About thirty minutes after the front edge of the giant cloud passed over the Wind probe, it swept over Japan's GEOTAIL satellite, which was located on the sunward side of the Earth in its 120,000 X 40,000 mile elliptical orbit. GEOTAIL also gathered important scientific data. Minutes later, the disturbance struck the outer limits of the Earth's magnetic field, which acts as a protective buffer. The impact compressed the magnetic field on the sunward side of the Earth and stretched it out away from the Sun on the night side, triggering the magnetic storm and aurora. "It was detected with instruments on Wind that sense the magnetic fields, particles and waves in interplanetary space," said Dr Ogilvie. "This is a good example of what we had been expecting since Wind was launched Nov. 1, 1994. This wonderful observation is a great first birthday present from Wind." A complete analysis of the Oct.18 Wind data, and data from other spacecraft and instruments, may take months or years, but is expected to tell scientists much about how interplanetary disturbances propagate through space and affect the Earth's environment. Future disturbances are anticipated as the 11-year sunspot cycle is expected to peak shortly after the year 2000, according to NASA scientists. EDITOR'S NOTE: A color drawing depicting the disturbance is available to news media representatives by calling the Headquarters Imaging Branch on 202/358-1900. Photo numbers are: Color: 95-HC-651 B&W: 95-H-664 Users of the Internet World Wide Web can obtain background information on Wind, GEOTAIL and related space missions, and view scientific data on the Oct. 18 disturbance at the following URL: http://bolero.gsfc.nasa.gov/~solart/cloud/cloud.html -end- NASA press releases and other information are available automatically by sending an Internet electronic mail message to domo@hq.nasa.gov. In the body of the message (not the subject line) users should type the words "subscribe press-release" (no quotes). The system will reply with a confirmation via E-mail of each subscription. A second automatic message will include additional information on the service. Questions should be directed to (202) 358-4043.