Satellites solve mystery of low gravity over Canada


	Satellites solve mystery of low gravity over Canada

Octane

5-27-2007 4:05 AM

479 views

tags:

canada, nasa, german aerospace center, physics, gravity, space, research

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<div style="margin: 12px 0px; font-family: arial; color: #333333; background: #ffffff; border: solid 4px #e5e5e5; width: 100%; clear: left;"><div class="CM_CTB_Content_Wrap" style="margin: 0px; padding: 0px;background-color: #ffffff;"><div style="border-bottom: solid 1px #dcdcdc; white-space: nowrap; margin-bottom: 8px; background-color: #eeeeee ;background-image: url(http://www.clipmarks.com/images/source-bg.gif); background-repeat: repeat-x; height: 24px; line-height: 24px; vertical-align: middle; padding-bottom: 4px; color: #666666; font-size: 10px;" ><a href="http://clipmarks.com/clip-to-blog/" title="see clips that are hot right now"><img src="http://content.clipmarks.com/blog_embed/2e469317-451a-41f4-8119-76f9934f317b/19989F67-EA63-429C-AFE1-91089C61B3DB/" alt="" width="19" height="19" border="0" style="vertical-align: middle; margin: 0px 4px; display: inline; border: none; float:none;" /></a>clipped from <a title="http://space.newscientist.com/article.ns?id=dn11826&feedId=space_rss20" href="http://space.newscientist.com/article.ns?id=dn11826&feedId=space_rss20" style="font-size: 11px;">space.newscientist.com</a></div><blockquote style="text-align: left; padding: 0px 8px; margin: 4px 0px 8px 0px; background: transparent; border: none;" cite="http://space.newscientist.com/article.ns?id=dn11826&feedId=space_rss20"><H2 class="inline">Satellites solve mystery of low gravity over Canada</H2></blockquote><div style="height: 2px; font-size: 2px; background: #dcdcdc; border-bottom: solid 1px #f5f5f5; margin: 2px 4px;"></div><blockquote style="text-align: left; padding: 0px 8px; margin: 4px 0px 8px 0px; background: transparent; border: none;" cite="http://space.newscientist.com/article.ns?id=dn11826&feedId=space_rss20"><P>If it seems Canadians weigh less than their American neighbours, they do – but not for the reasons you might think. A large swath of Canada actually boasts lower gravity than its surroundings.</P></blockquote><div style="height: 2px; font-size: 2px; background: #dcdcdc; border-bottom: solid 1px #f5f5f5; margin: 2px 4px;"></div><blockquote style="text-align: left; padding: 0px 8px; margin: 4px 0px 8px 0px; background: transparent; border: none;" cite="http://space.newscientist.com/article.ns?id=dn11826&feedId=space_rss20"><P>Researchers have puzzled for years over whether this was due to the crust there rebounding slowly after the end of the last ice age or a deeper issue involving convection in the Earth's mantle – or some combination of the two.</P></blockquote><div style="height: 2px; font-size: 2px; background: #dcdcdc; border-bottom: solid 1px #f5f5f5; margin: 2px 4px;"></div><blockquote style="text-align: left; padding: 0px 8px; margin: 4px 0px 8px 0px; background: transparent; border: none;" cite="http://space.newscientist.com/article.ns?id=dn11826&feedId=space_rss20"><P>Now, ultra-precise measurements taken over four years by a pair of satellites known as GRACE (Gravity Recovery and Climate Experiment) reveal that each effect is equally responsible for Canada's low gravity. The work could shed light on how continents form and evolve over time.</P></blockquote><div style="height: 2px; font-size: 2px; background: #dcdcdc; border-bottom: solid 1px #f5f5f5; margin: 2px 4px;"></div><blockquote style="text-align: left; padding: 0px 8px; margin: 4px 0px 8px 0px; background: transparent; border: none;" cite="http://space.newscientist.com/article.ns?id=dn11826&feedId=space_rss20">The two spacecraft fly 500 kilometres above the Earth, 220 kilometres apart. Using a microwave ranging system, the two spacecraft can measure distance differences between them as tiny as a micron.</blockquote></div><div style="margin: 0px 6px 6px 4px;"><table style="font-size: 11px;border-spacing: 0px;padding: 0px;" cellpadding="0" cellspacing="0" width="100%"><tr><td style="background:transparent;border-width:0px;padding:0px;">&nbsp;</td><td align="right" style="background:transparent;border-width:0px;padding:0px;width:107px" width="107"><a href="http://clipmarks.com/share/19989F67-EA63-429C-AFE1-91089C61B3DB/blog/" title="blog or email this clip"><img src="http://content6.clipmarks.com/images/c2b-foot.png" border="0" alt="blog it" width="107" height="17" style="border-width:0px;padding:0px;margin:0px;" /></a></td></tr></table></div></div>