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ACE of Goddard Space Flight Center (GSFC) and Jet Propulsion Laboratory (JPL)
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The Sun's Heliosphere & Heli
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The Sun's Heliosphere & Heliopause |
| Explanation |
Where does the Sun's influence end? Nobody is sure. Out past the orbits of Neptune [ http://antwrp.gsfc.nasa.gov/apod/neptune.html ] and Pluto [ http://www.nineplanets.org/pluto.html ] extends a region named the heliosphere [ http://science.msfc.nasa.gov/ssl/pad/solar/heliosph.htm ] where the Sun's magnetic field [ http://science.msfc.nasa.gov/ssl/pad/solar/the_key.htm ] and particles from the Solar Wind [ http://science.msfc.nasa.gov/ssl/pad/solar/sun_wind.htm ] continue to dominate. The surface where the Solar Wind [ http://antwrp.gsfc.nasa.gov/apod/ap000318.html ] drops below sound speed [ http://antwrp.gsfc.nasa.gov/apod/ap010221.html ] is called the termination shock [ http://web.mit.edu/space/www/voyager/voyager_science/helio.review/axford.suess.html#Distance ] and is depicted as the inner oval in the above computer-generated illustration [ http://www.cs.indiana.edu/~soljourn/ ]. It is thought that this surface occurs as close as 75-90 AU [ http://neo.jpl.nasa.gov/glossary/au.html ] -- so close that a Pioneer [ http://spaceprojects.arc.nasa.gov/Space_Projects/pioneer/PNhome.html ] or Voyager [ http://voyager.jpl.nasa.gov/ ] spacecraft may soon glide through [ http://www.srl.caltech.edu/personnel/ace/recentpub/JGR_96/pap_preprint.html ] it as they exit the Solar System [ http://antwrp.gsfc.nasa.gov/apod/ap020214.html ] at about 3 AU/year. The actual contact sheet between the Sun's ions [ http://www-istp.gsfc.nasa.gov/Education/wplasma.html ] and the Galaxy's ions is called the heliopause [ http://www-pw.physics.uiowa.edu/plasma-wave/voyager/heliopr.html ] and is thought to occur at about 110 AU. It is depicted above as the middle surface. The Sun's heliopause [ http://web.mit.edu/space/www/voyager/voyager_science/helio.review/axford.suess.html ] moves through the local interstellar medium [ http://antwrp.gsfc.nasa.gov/apod/ap020210.html ] much as a boat moves on water, pushing a bow shock [ http://antwrp.gsfc.nasa.gov/apod/ap001017.html ] out in front, thought to occur near 230 AU. |
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MISR Participates in Aerosol
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PIA03404
Sol (our sun)
Multi-angle Imaging SpectroR
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MISR Participates in Aerosol Characterization Experiment over Asia |
| Original Caption Released with Image |
Before scientists apply new spacecraft measurements to global climate change research, they must carefully test their understanding of the data under controlled conditions. During April 2001, a team of 200 investigators from 11 countries participated in the Aerosol Characterization Experiment (ACE) field campaign in Asia, deploying instruments aboard several ships, aircraft, and island stations in the waters surrounding Japan and Korea. They characterized meteorological conditions, measured the atmospheric energy balance, and directly sampled airborne dust and pollution particles while the Multi-angle Imaging SpectroRadiometer (MISR) and other satellite instruments flew overhead. These MISR images, centered just north of Shikoku Island in southwest Japan, were acquired on April 13, 2001 during Terra orbit 7015. They are two of nine simultaneous views obtained at different angles by the instrument, at 26 degrees aft of vertical (left) and 60 degrees forward of vertical (right). The entire west end of Honshu Island, which crosses the upper half of the images, is covered with broken clouds. Away from the clouds, the atmosphere looks hazier in the steeper MISR view, such differences reveal information about particles in the atmosphere. As these images were taken, the U.S. National Oceanographic and Atmospheric Administration (NOAA) Research Vessel Ron Brown and the National Science Foundation (NSF)/National Center for Atmospheric Research (NCAR) C-130 aircraft probed the environment near Oki island, in the upper left part of the images. At the same time, the Center for Interdisciplinary Remotely Piloted Aircraft Studies (CIRPAS) Twin Otter aircraft made atmospheric chemistry and heat-balance measurements in the bottom-center region of the images. For more about ACE-Asia, see http://saga.pmel.noaa.gov/aceasia/ [ http://saga.pmel.noaa.gov/aceasia/ ] MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Office of Earth Science, Washington, DC. The Terra satellite is managed by NASA's Goddard Space Flight Center, Greenbelt, MD. JPL is a division of the California Institute of Technology. |
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