[FPSPACE] FW: SwRI: IBEX Detects Fast Neutral Hydrogen from the Moon
ljk4 at msn.com
Thu Jun 18 13:07:18 EDT 2009
> Date: Thu, 18 Jun 2009 11:56:15 -0400
> Subject: SwRI: IBEX Detects Fast Neutral Hydrogen from the Moon
> From: rick.fienberg at aas.org
> To: Rick.Fienberg at aas.org
> THE FOLLOWING RELEASE WAS RECEIVED FROM THE SOUTHWEST RESEARCH
> INSTITUTE IN SAN ANTONIO, TEXAS, AND IS FORWARDED FOR YOUR
> INFORMATION. (FORWARDING DOES NOT IMPLY ENDORSEMENT BY THE AMERICAN
> ASTRONOMICAL SOCIETY.) Rick Fienberg, American Astronomical Society:
> rick.fienberg at aas.org, 1-857-891-5649.
> June 18, 2009
> Contact: Maria Martinez
> 1 (210) 522-3305
> mmartinez at swri.org
> IBEX SPACECRAFT DETECTS FAST NEUTRAL HYDROGEN
> COMING FROM THE MOON, GIVES INSIGHT TO
> PARTICLE “RECYCLING” PROCESSES IN SPACE
> San Antonio -- NASA’s Interstellar Boundary Explorer (IBEX) spacecraft
> has made the first observations of very fast hydrogen atoms coming
> from the Moon, following decades of speculation and searching for
> their existence.
> During spacecraft commissioning, the IBEX team turned on the IBEX-Hi
> instrument, built primarily by Southwest Research Institute (SwRI) and
> the Los Alamos National Laboratory, which measures atoms with speeds
> from about half a million to 2.5 million miles per hour. Its companion
> sensor, IBEX-Lo, built by Lockheed Martin, the University of New
> Hampshire, NASA Goddard Space Flight Center, and the University of
> Bern in Switzerland, measures atoms with speeds from about one hundred
> thousand to 1.5 million mph.
> “Just after we got IBEX-Hi turned on, the Moon happened to pass right
> through its field of view, and there they were,” says Dr. David J.
> McComas, IBEX principal investigator and assistant vice president of
> the SwRI Space Science and Engineering Division. “The instrument lit
> up with a clear signal of the neutral atoms being detected as they
> backscattered from the Moon.”
> The solar wind, the supersonic stream of charged particles that flows
> out from the Sun, moves out into space in every direction at speeds of
> about a million mph. The Earth’s strong magnetic field shields our
> planet from the solar wind. The Moon, with its relatively weak
> magnetic field, has no such protection, causing the solar wind to slam
> onto the Moon’s sunward side.
> From its vantage point in space, IBEX sees about half of the Moon --
> one quarter of it is dark and faces the nightside (away from the Sun),
> while the other quarter faces the dayside (toward the Sun). Solar wind
> particles impact only the dayside, where most of them are embedded in
> the lunar surface, while some scatter off in different directions. The
> scattered ones mostly become neutral atoms in this reflection process
> by picking up electrons from the lunar surface.
> The IBEX team estimates that only about 10 percent of the solar wind
> ions reflect off the sunward side of the Moon as neutral atoms, while
> the remaining 90 percent are embedded in the lunar surface.
> Characteristics of the lunar surface, such as dust, craters and rocks,
> play a role in determining the percentage of particles that become
> embedded and the percentage of neutral particles, as well as their
> direction of travel, that scatter.
> McComas says the results also shed light on the “recycling” process
> undertaken by particles throughout the solar system and beyond. The
> solar wind and other charged particles impact dust and larger objects
> as they travel through space, where they backscatter and are
> reprocessed as neutral atoms. These atoms can travel long distances
> before they are stripped of their electrons and become ions and the
> complicated process begins again.
> The combined scattering and neutralization processes now observed at
> the Moon have implications for interactions with objects across the
> solar system, such as asteroids, Kuiper Belt objects and other Moons.
> The plasma-surface interactions occurring within protostellar nebula,
> the region of space that forms around planets and stars -- as well as
> exoplanets, planets around other stars -- also can be inferred.
> IBEX’s primary mission is to observe and map the complex interactions
> occurring at the edge of the solar system, where the million miles per
> hour solar wind runs into the interstellar material from the rest of
> the galaxy. The spacecraft carries the most sensitive neutral atom
> detectors ever flown in space, enabling researchers to not only
> measure particle energy, but also to make precise images of where they
> are coming from.
> Around the end of the summer, the team will release the spacecraft’s
> first all-sky map showing the energetic processes occurring at the
> edge of the solar system. The team will not comment until the image is
> complete, but McComas hints, “It doesn’t look like any of the models.”
> # # #
> IBEX is the latest in NASA’s series of low-cost, rapidly developed
> Small Explorers spacecraft. The IBEX mission was developed by SwRI
> with a national and international team of partners. NASA’s Goddard
> Space Flight Center manages the Explorers Program for NASA’s Science
> Mission Directorate.
> “Lunar Backscatter and Neutralization of the Solar Wind: First
> Observations of Neutral Atoms from the Moon,” by McComas, F.
> Allegrini, P. Bochsler, P. Frisch, H.O. Funsten, M. Gruntman, P.H.
> Janzen, H. Kucharek, E. Moebius, D.B. Reisenfeld, and N.A. Schwadron,
> was just published by Geophysical Research Letters,
> Editors: An image to accompany this story is available at
> For more information on IBEX, visit
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> Fienberg, AAS Deputy Press Officer: rick.fienberg at aas.org, telephone
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