Sedna的精選

PerhapsamassiveunseenobjectisresponsibleforSedna'smystifyingorbit,itsgravitationalinfluencekeepingSednafixedinthatfar-distantportionofspace.一顆近期被發現的褐矮星“賽德娜”(Sedna)有一個超長的橢圓形的...