The Earth's Magnetosphere
In spite of its low density, the solar wind, and its accompanying magnet field, is strong enough to interact with the planets and their magnetic fields to shape magnetospheres. A magnetosphere is the region surrounding a planet where the planet's magnetic field dominates. Because the ions in the solar plasma are charged, they interact with these magnetic fields, and solar wind particles are swept around planetary magnetospheres. Life on Earth has developed under the protection of this magnetosphere.
The shape of the Earth's magnetosphere is the direct result of being blasted by solar wind. Solar wind compresses its sunward side to a distance of only 6 to 10 times the radius of the Earth. A supersonic shock wave is created sunward of Earth somewhat like a sonic boom. This shock wave is called the bow shock. Most of the solar wind particles are heated and slowed at the bow shock and detour around the Earth. Solar wind drags out the night-side magnetosphere to possibly 1000 times Earth's radius; its exact length is not known. This extension of the magnetosphere is known as the magnetotail. Many other planets in our solar system have magnetospheres of similar, solar wind-influenced shapes. More about the magnetosphere... Still more about the magnetosphere... Dynamic modeling of the Earth's bow shock and magnetopause -- Real time data from the ACE spacecraft are used to predict the shape and location of these boundaries at the present time and into the near future. -- from Polar/PIXIE
QuickTime movie of the effects of space weather on the magnetosphere -- UCLA
Earth's Magnetosphere in the News:
July 21, 2009: NASA's
Magnetospheric MultiScale Mission takes a step closer to solving the
mystery behind magnetic reconnection -- NASA July 2, 2009: AGU journal highlights -- #11 -- Eurekalert June 22, 2009: Shifts in Earth's magnetic field driven by oceans? -- National Geographic June 14, 2009: The Earth's magnetic field remains a charged mystery -- IOP June 14, 2009: Earth's magnetic field perturbed by 'electric oceans', claims researcher -- Physics World June 2, 2009: Magnetic tornadoes could liberate Mercury's tenuous atmosphere -- NASA May 29, 2009: Sun stealing Earth's atmosphere -- National Geographic May 29, 2009: Waves in Earth's radiation belt get mapped -- Science Daily May 27, 2009: Bricks, mortar and magnetism -- Science News May 11, 2009: "Supergiant" asteroid shut down Mars's magnetic field -- National Geographic April 30, 2009: Magnetic twisters "dance" across Mercury, study says -- National Geographic -- April 30, 2009: Active Mercury -- Science@NASA April 29, 2009: Watching solar activity muddle Earth's magnetic field -- ESA April 24, 2009: Multipolar dance could flip Earth's magnetic field -- Physics World February 11, 2009: ESA extends missions studying Mars, Venus and Earth's magnetosphere [last article] -- ESA January 8, 2009: Magnetic fields could reveal exoplanets -- Physics World January 7, 2009: "Warm plasma cloak" discovered enveloping Earth -- National Geographic December 16, 2008: Sun often "tears out a wall" in Earth's solar storm shield -- NASA THEMIS December 15, 2008: A giant breach in Earth's magnetic field -- Science@NASA October 30, 2008: Magnetic portals connect Sun and Earth -- Science@NASA September 25, 2008: Lava flows reveal clues to magnetic field reversals -- University of Wisconsin - Madison August 28, 2008: Cluster watches Earth's leaky atmosphere -- ESA July 19, 2008: Asteroid switched Mars' magnetic field on and off -- New Scientist July 10, 2008: Enhanced color Caloris -- APOD June 30, 2008: Earth's core, magnetic field changing fast, study says -- National Geographic June 23, 2008: XMM-Newton watches lazy pulsar being jazzed up by companion -- ESA June 4, 2008: Iron snow behind Mercury's magnetism -- Scientific American June 2, 2008: Building a baby Earth to test its magnetic field -- NPR May 8, 2008: Iron 'snow' helps maintain Mercury's magnetic field -- Astronomy.com April 30, 2008: Team of researchers explain how birds navigate -- ASU April 30, 2008: 'Chemical compass' created -- Nature April 28, 2008: 'Broken heart' image the last for NASA's long-lived Polar mission -- NASA GSFC April 17, 2008: The moon and the magnetotail -- Science@NASA March 13, 2008: Japanese satellite first to use magnetic memory -- Scientific American March 9, 2008: New discovery at Jupiter could help protect Earth-orbit satellites -- Eurekalert February 25, 2008: Killer electrons surf celestial tsunamis -- NASA GSFC February 1, 2008: The first Explorer -- APOD January 31, 2008: New discovery on magnetic reconnection to impact future space missions -- Science Daily January 30, 2008: Mercury's magnetosphere fends off the solar wind -- Eurekalert December 31, 2007: Titan's plasma wake (see #16) -- Eurekalert December 20, 2007: News from Earth's magnetic field -- Eurekalert December 13, 2007: Earth's protective magnetic field -- Astronomy.com December 13, 2007: Earth's magnetosphere: On the ropes -- Sky & Telescope December 11, 2007: Earth's magnetic field could help protect astronauts working on the moon -- Eurekalert November 28, 2007: UNH scientists report first findings on key astrophysics problem -- Eurekalert October 3, 2007: Comet Encke's tail ripped off -- APOD September 12, 2007: Cluster and Double Star uncover more on bright aurorae -- Science Daily August 22, 2007: What makes Mars magnetic? -- Spaceflight Now August 1, 2007: Mmmm, space chips -- Popular Science June 1, 2007: Pioneering 3D view of near-Earth magnetic 'dance' -- Science Daily April 13, 2007: Cluster sees tsunamis in space -- SpaceDaily March 29, 2007: Magnetic fields get reconnected in turbulent plasma too, Cluster reveals -- SpaceDaily March 12, 2007: Cluster opens a new window on 'magnetic reconnection' in the near-Earth space -- EurekAlert! February 20, 2007: Lockheed Martin scientists determine magnetic reconnection locations at Earth's magnetopause -- SpaceDaily February 9, 2007: Cluster - new insights into the electric circuits of polar lights -- European Space Agency January 24, 2007: Storm hunt: spacecraft quintet to track down magnetic field tempests -- Space.com Click on images above to
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