{"id":647,"date":"2006-09-27T08:09:14","date_gmt":"2006-09-27T08:09:14","guid":{"rendered":"http:\/\/scienceblogs.com\/principles\/2006\/09\/27\/that-my-liege-is-how-we-know-t-1\/"},"modified":"2006-09-27T08:09:14","modified_gmt":"2006-09-27T08:09:14","slug":"that-my-liege-is-how-we-know-t-1","status":"publish","type":"post","link":"http:\/\/chadorzel.com\/principles\/2006\/09\/27\/that-my-liege-is-how-we-know-t-1\/","title":{"rendered":"That, My Liege, Is How We Know the Earth to Be Banana Shaped"},"content":{"rendered":"

The AIP news feed features a story about a paper suggesting that the universe is ellipsoidal<\/a>. Or at least, that it was, back in the early days.<\/p>\n

The work is based on the famous WMAP picture of the microwave background (and no, it’s not because the picture is oblong):<\/p>\n

\"i-f5fce7e4a436e519d364cc18fa24c0ab-med_wiener_map.gif\"<\/p>\n

As you know, Bob, the picture shows the distribution of temperature fluctuations in the early universe. These temperature correlations correspond to slight variations in the density of matter at that time, density fluctuations that eventually evolved into galaxies and galaxy clusters.<\/p>\n

(Explanation after the cut.)<\/p>\n

<\/p>\n

We can’t directly compare this measured distribution to the current distribution of matter that we see, or to theoretical models, but it is possible to do a statistical sort of comparison. Mathematically, this is expressed in terms of functions called “spherical harmonics” (the term “moments” is also used), but the basic idea is just a measurement of how likely you are to find a structure of a particular angular size. Basically, you measure how frequently blobs of a certain size occur in the WMAP image, and compare that the frequency at which blobs of that size occur in theoretically generated plots of temperature fluctuations.<\/p>\n

These comparisons work very nicely for a certain class of theoretical models, with one exception. The models all predict more structure at larger scales than is seen in the WMAP image– there’s a nice summary graph at the bottom of this page<\/a>. The problem is that the theory curve turns up at the left-hand edge of the graph, while the experimental points drop down.<\/p>\n

The new claim being touted by AIP is that this arises naturally from a model in which the early universe is not spherically symmetric, but is stretched very slightly (about one percent) in some direction. The authors claim that by introducing a slight bulge, they can exactly match the WMAP data. This could be caused by a magnetic field filling all of space, or the wonderfully Star Trek<\/cite> sounding “a defect in the fabric of spacetime.”<\/p>\n

How solid is this result? Beats me. This isn’t my field at all, but maybe Steinn<\/a> will have something to say. I mostly just wanted to use the Python quote in the post title…<\/p>\n","protected":false},"excerpt":{"rendered":"

The AIP news feed features a story about a paper suggesting that the universe is ellipsoidal. Or at least, that it was, back in the early days. The work is based on the famous WMAP picture of the microwave background (and no, it’s not because the picture is oblong): As you know, Bob, the picture… Continue reading That, My Liege, Is How We Know the Earth to Be Banana Shaped<\/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":[10,33,7,11],"tags":[],"class_list":["post-647","post","type-post","status-publish","format-standard","hentry","category-astronomy","category-in_the_news","category-physics","category-science","entry"],"_links":{"self":[{"href":"http:\/\/chadorzel.com\/principles\/wp-json\/wp\/v2\/posts\/647","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=647"}],"version-history":[{"count":0,"href":"http:\/\/chadorzel.com\/principles\/wp-json\/wp\/v2\/posts\/647\/revisions"}],"wp:attachment":[{"href":"http:\/\/chadorzel.com\/principles\/wp-json\/wp\/v2\/media?parent=647"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chadorzel.com\/principles\/wp-json\/wp\/v2\/categories?post=647"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chadorzel.com\/principles\/wp-json\/wp\/v2\/tags?post=647"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}