{"id":13445,"date":"2017-08-10T00:49:25","date_gmt":"2017-08-09T22:49:25","guid":{"rendered":"http:\/\/karmaka.de\/?p=13445"},"modified":"2017-08-10T01:14:32","modified_gmt":"2017-08-09T23:14:32","slug":"a-two-billion-year-history-for-the-lunar-dynamo","status":"publish","type":"post","link":"https:\/\/karmaka.de\/?p=13445","title":{"rendered":"A two-billion-year history for the lunar dynamo<span class=\"badge-status\" style=\"background:#787878\">OPEN ACCESS<\/span>&nbsp;"},"content":{"rendered":"<p>Sonia M. Tikoo, Benjamin P. Weiss, David L. Shuster, Cl\u00e9ment Suavet, Huapei Wang and Timothy L. Grove<\/p>\n<p>Science Advances  09 Aug 2017:<br \/>\nVol. 3, no. 8, e1700207<br \/>\nDOI: 10.1126\/sciadv.1700207<\/p>\n<p><a href=\"http:\/\/advances.sciencemag.org\/content\/3\/8\/e1700207.full\" target=\"_blank\"><strong>LINK (OPEN ACCESS)<\/strong><\/a><br \/>\n<a href=\"http:\/\/advances.sciencemag.org\/content\/3\/8\/e1700207.full.pdf\" target=\"_blank\"><strong>PDF (OPEN ACCESS)<\/strong><\/a><br \/>\n<a href=\"http:\/\/advances.sciencemag.org\/highwire\/filestream\/197649\/field_highwire_adjunct_files\/2\/1700207_SM.pdf\" target=\"_blank\">SUPPLEMENTARY MATERIALS (PDF)<\/a><\/p>\n<p>&#8220;Magnetic studies of lunar rocks indicate that the Moon generated a core dynamo with surface field intensities of ~20 to 110 \u03bcT between at least 4.25 and 3.56 billion years ago (Ga). The field subsequently declined to <~4 \u03bcT by 3.19 Ga, but it has been unclear whether the dynamo had terminated by this time or just greatly weakened in intensity. We present analyses that demonstrate that the melt glass matrix of a young regolith breccia was magnetized in a ~5 \u00b1 2 \u03bcT dynamo field at ~1 to ~2.5 Ga. These data extend the known lifetime of the lunar dynamo by at least 1 billion years. Such a protracted history requires an extraordinarily long-lived power source like core crystallization or precession. No single dynamo mechanism proposed thus far can explain the strong fields inferred for the period before 3.56 Ga while also allowing the dynamo to persist in such a weakened state beyond ~2.5 Ga. Therefore, our results suggest that the dynamo was powered by at least two distinct mechanisms operating during early and late lunar history.\"\n<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Sonia M. Tikoo, Benjamin P. Weiss, David L. Shuster, Cl\u00e9ment Suavet, Huapei Wang and Timothy L. Grove Science Advances 09 Aug 2017: Vol. 3, no. 8, e1700207 DOI: 10.1126\/sciadv.1700207 LINK (OPEN ACCESS) PDF (OPEN ACCESS)&#8230;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[115,219],"tags":[218,1857,590],"_links":{"self":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/13445"}],"collection":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=13445"}],"version-history":[{"count":2,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/13445\/revisions"}],"predecessor-version":[{"id":13453,"href":"https:\/\/karmaka.de\/index.php?rest_route=\/wp\/v2\/posts\/13445\/revisions\/13453"}],"wp:attachment":[{"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=13445"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=13445"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/karmaka.de\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=13445"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}