{"id":2041,"date":"2011-07-23T19:39:51","date_gmt":"2011-07-24T02:39:51","guid":{"rendered":"https:\/\/www.wkiri.com\/today\/?p=2041"},"modified":"2011-07-23T19:41:09","modified_gmt":"2011-07-24T02:41:09","slug":"pluto-has-four-moons","status":"publish","type":"post","link":"https:\/\/www.wkiri.com\/today\/?p=2041","title":{"rendered":"Pluto has four moons!"},"content":{"rendered":"<p>Recently I read the announcement that <a href=\"http:\/\/science.nasa.gov\/science-news\/science-at-nasa\/2011\/20jul_p4\/\">astronomers found a fourth moon orbiting Pluto<\/a> in Hubble Space Telescope observations.  Apparently they were not looking for more moons; instead, they were looking for possible rings around Pluto.<\/p>\n<p>My first thought: Wait, Pluto had three moons before?<\/p>\n<p>I blush to admit that I only knew of Charon, Pluto&#8217;s largest moon (1207 km in diameter).  I missed the announcement in 2005 of the discovery of two more Pluto moons: <a href=\"http:\/\/en.wikipedia.org\/wiki\/Nix_%28moon%29\">Nix<\/a> (46-137 km) and <a href=\"http:\/\/en.wikipedia.org\/wiki\/Hydra_%28moon%29\">Hydra<\/a> (61-167 km).  Now&#8217;s a good time to catch up!  The new moon (temporarily designated <a href=\"http:\/\/en.wikipedia.org\/wiki\/S\/2011_P_1\">P4 as &#8220;Pluto&#8217;s 4th satellite&#8221;<\/a>) is only 13-34 km in diameter.   That&#8217;s small, but there is precedent: Phobos and Deimos, the moons of Mars, are only 20 and 15 km in diameter respectively.<\/p>\n<p>Here is a composite of two images that provides the basis of the new moon&#8217;s discovery:<\/p>\n<p><a href=\"http:\/\/www.nasa.gov\/images\/content\/571868main_i1123ay.jpg\"><img decoding=\"async\" width=400 src=\"http:\/\/science.nasa.gov\/media\/medialibrary\/2011\/07\/20\/splash2_strip.jpg\"><\/a><\/p>\n<p>The timing of this serendipitous discovery is excellent.  The <a href=\"http:\/\/pluto.jhuapl.edu\/\">New Horizons<\/a> mission will fly past Pluto in July of 2015, and perhaps it will have the chance to investigate P4 up close &#8212; or even add more moons to Pluto&#8217;s tiny family!<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Recently I read the announcement that astronomers found a fourth moon orbiting Pluto in Hubble Space Telescope observations. Apparently they were not looking for more moons; instead, they were looking for possible rings around Pluto. My first thought: Wait, Pluto had three moons before? I blush to admit that I only knew of Charon, Pluto&#8217;s [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[36],"tags":[],"_links":{"self":[{"href":"https:\/\/www.wkiri.com\/today\/index.php?rest_route=\/wp\/v2\/posts\/2041"}],"collection":[{"href":"https:\/\/www.wkiri.com\/today\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.wkiri.com\/today\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.wkiri.com\/today\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.wkiri.com\/today\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=2041"}],"version-history":[{"count":7,"href":"https:\/\/www.wkiri.com\/today\/index.php?rest_route=\/wp\/v2\/posts\/2041\/revisions"}],"predecessor-version":[{"id":2048,"href":"https:\/\/www.wkiri.com\/today\/index.php?rest_route=\/wp\/v2\/posts\/2041\/revisions\/2048"}],"wp:attachment":[{"href":"https:\/\/www.wkiri.com\/today\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=2041"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.wkiri.com\/today\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=2041"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.wkiri.com\/today\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=2041"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}