Sedna的精选

PerhapsamassiveunseenobjectisresponsibleforSedna'smystifyingorbit,itsgravitationalinfluencekeepingSednafixedinthatfar-distantportionofspace.一颗近期被发现的褐矮星“赛德娜”(Sedna)有一个超长的椭圆形的...