... Tonight's Sky . ... Moon . ... Observing . ... One Sedna mystery solved . What influences Sedna's lethargic rotation speed? ... CfA astronomer Scott Gaudi and his colleagues have solved the case of Sedna's missing moon. ... Unlike the first Sedna mystery, these answers will not be as easily resolved. ... Only registered members of Astronomy.com are allowed to comment on this article. ... Receive news, sky-event information, observing tips, and more from Astronomy's weekly email newsletter. ...