http://wiki.newmars.com/index.php?action=history&feed=atom&title=Magnetic_fields_of_Mars 2026-05-25T12:18:57Z Revision history for this page on the wiki MediaWiki 1.29.1 http://wiki.newmars.com/index.php?title=Magnetic_fields_of_Mars&diff=299&oldid=prev 2009-01-21T11:02:31Z

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Josh Cryer http://wiki.newmars.com/index.php?title=Magnetic_fields_of_Mars&diff=298&oldid=prev 2009-01-20T13:14:20Z

<p>Reverted edit of TadroNcnab, changed back to last version by Noosfractal</p> <p><b>New page</b></p><div>[[Image:Mars magnetic fields 01.jpg|thumb|200px|right|Local magnetic fields on Mars]]<br /> Unlike Earth, Mars has no strong global magnetic field, only weak local ones are present.<br /> <br /> Surveys in the 1990s of magnetic fields on Mars, by the orbiting [[Mars Global Surveyor]], detected the signatures of relatively intense magnetism in some of the planet&#039;s more modern surfaces. But the fields were found to be very weak in two large and old impact basis, Hellas and Argyre. Each basin, carved out by a colossal space asteroid, is more than 3 billion years old. The data implied that Mars had a weak magnetic field back then.<br /> <br /> New research calls into question the validity of measuring magnetism from an orbital perch. It has been found that rocks in the 2-billion-year-old Vredefort impact crater in South Africa -- the oldest such structure on Earth -- are highly magnetized, yet from above the magnetism appears weak. Two other ancient craters reveal similar differences.<br /> <br /> The basic reason is simple: While magnetism is strong in individual rocks, the direction varies from rock to rock in these impact craters, so when examined from a distance, they cancel each other out.<br /> <br /> So, viewed from a high altitude of 100-400 km, certain areas of Mars might appear magnetically featureless if the magnetic vectors of their source rocks vary in direction over distances of a few kilometers or less.<br /> <br /> ==Geological implications==<br /> Magnetic fields on Mars are &quot;striped&quot;, a feature that clearly shows that Mars had crustal plates movement in its history. Stripe patterns like these are widespread on Earth – particularly along the Mid-Atlantic Ridge.<br /> <br /> {{MainArticle|[[Geology of Mars]]}}<br /> <br /> [[Category:Marsian features]]</div>

Josh Cryer