{"id":518,"date":"2006-08-21T13:43:26","date_gmt":"2006-08-21T13:43:26","guid":{"rendered":"http:\/\/scienceblogs.com\/principles\/2006\/08\/21\/in-the-dark-no-more\/"},"modified":"2006-08-21T13:43:26","modified_gmt":"2006-08-21T13:43:26","slug":"in-the-dark-no-more","status":"publish","type":"post","link":"http:\/\/chadorzel.com\/principles\/2006\/08\/21\/in-the-dark-no-more\/","title":{"rendered":"In the Dark No More"},"content":{"rendered":"<p>As <a href=\"http:\/\/scienceblogs.com\/principles\/2006\/08\/keeping_us_in_the_dark.php\">hinted last week<\/a>, the Chandra X-Ray Observatory has some new results conclusively showing that dark matter is a real, physical thing. This is big news, because the previous evidence for dark matter was all indirect, and based on inferring the mass distribution of galaxies and clusters of galaxies from looking at their motion. These results could indicate the presence of dark matter, or they could point to a flaw in our understanding of gravity at extremely long ranges.<\/p>\n<p>The <a href=\"http:\/\/chandra.harvard.edu\/press\/06_releases\/press_082106.html\">new observation<\/a> shows fairly conclusively that dark matter and ordinary matter are different things, by combining two different observations: graviational lensing of distant objects by a cluster of galaxies, to show where the mass of the cluster is concentrated, and X-ray observations of the hot gas associated with the cluster, to show the mass distribution of ordinary matter in the cluster. These turn out to be in two very different places, showing that the gas cannot account for the mass distribution, even if we fiddle with the mechanics of gravity.<\/p>\n<p>Sean Carroll, who was on the panel NASA put together to announce the result, has a <a href=\"http:\/\/cosmicvariance.com\/2006\/08\/21\/dark-matter-exists\/\">very nice explanation<\/a> of the whole thing. With spiffy pictures!<\/p>\n","protected":false},"excerpt":{"rendered":"<p>As hinted last week, the Chandra X-Ray Observatory has some new results conclusively showing that dark matter is a real, physical thing. This is big news, because the previous evidence for dark matter was all indirect, and based on inferring the mass distribution of galaxies and clusters of galaxies from looking at their motion. These&hellip; <a class=\"more-link\" href=\"http:\/\/chadorzel.com\/principles\/2006\/08\/21\/in-the-dark-no-more\/\">Continue reading <span class=\"screen-reader-text\">In the Dark No More<\/span><\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"1","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[10,33,11],"tags":[],"class_list":["post-518","post","type-post","status-publish","format-standard","hentry","category-astronomy","category-in_the_news","category-science","entry"],"_links":{"self":[{"href":"http:\/\/chadorzel.com\/principles\/wp-json\/wp\/v2\/posts\/518","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/chadorzel.com\/principles\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chadorzel.com\/principles\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chadorzel.com\/principles\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"http:\/\/chadorzel.com\/principles\/wp-json\/wp\/v2\/comments?post=518"}],"version-history":[{"count":0,"href":"http:\/\/chadorzel.com\/principles\/wp-json\/wp\/v2\/posts\/518\/revisions"}],"wp:attachment":[{"href":"http:\/\/chadorzel.com\/principles\/wp-json\/wp\/v2\/media?parent=518"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chadorzel.com\/principles\/wp-json\/wp\/v2\/categories?post=518"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chadorzel.com\/principles\/wp-json\/wp\/v2\/tags?post=518"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}