[27]Not so lonely sea in the sky.

感谢收听,期待你对本期节目的评论留言哦～ Science and technology Oceans in space Not so lonely sea in the sky Pluto[’plʊto]冥王星 is the latest place thought to have subsurface['sʌbsɜːfɪs]地下的 waters. Is the solar system about to get another ocean? So far, besides Earth, six bodies are known or suspected to harbour藏匿 oceans. These are Europa[juə'rəupə]木卫二, Callisto[kə'listəu]木卫四 and Ganymede木卫三['ɡænimi:d] (all moons of Jupiter['dʒuːpɪtə]木星), Enceladus[en'selədəs]土卫二 and Titan[taɪtn]土卫六 (both moons of Saturn['sæt(ə)n]土星) and Triton ['traɪtn]海卫一(a moon of Neptune[ˈneptju:n]海王星). The latest candidate is Pluto, the most famous inhabitant[ɪn'hæbɪt(ə)nt]居住者 of the Kuiper belt柯伊伯带, a girdle['gɜːd(ə)l]带 of asteroids ['æstərɔidz]小行星that orbit ['ɔːbɪt]绕轨道运行the sun beyond Neptune. Pluto’s claim to an ocean, argued this week in two papers published in Nature, is based on data collected in 2015 by New Horizons, a robotic[rəʊˈbɒtɪk]自动的 spacecraft航天器 that zoomed[zuːm]急速上升 past it in July of that year. The ocean in question, if it exists, is beneath在......下方 Pluto’s surface. That makes it unlike Earth’s ocean, but like those of the other six bodies. To human sensibilities that is,perhaps, a funny sort of ocean. But add it to the other six and it is Earth’s surface ocean that looks anomalous[ə'nɒm(ə)ləs]异常的, rather than Pluto’s buried one. The argument for a Plutonic[plʊ'tɑnɪk] ocean—advanced by teams led by Francis Nimmo of the University of California, Santa Cruz,and James Keane, of the University of Arizona[,æri'zəunə]亚利桑那州,Tucson['tu:sɔn]（城市名）, centres on Sputnik['spʌtnɪk] Planitia史泼尼克平原，a basin['beɪs(ə)n] 盆地1,300km across ,caused by a collision[kə'lɪʒ(ə)n]碰撞 in Pluto’s distant past.Pluto and its largest moon, Charon['kɛrən], are tidally潮水似地 locked. As they orbit their common centre of gravity, they always show each other the same face and, relative to the horizon, the position in the sky of either observed from the other never changes. The curiosity is that Sputnik Planitia lies almost exactly on the opposite side of Pluto from Charon, on the “tidal axis[ˈæksɪs]轴线”, a line that runs through the centre of both bodies. That is quite a coincidence[kəʊ'ɪnsɪd(ə)ns]—or, rather, in Dr Nimmo’s view it isn’t. He calculates the odds of it happening by chance as one in 20. He would therefore prefer to believe there is a physical explanation. And there might be. If Sputnik Planitia were an anomalously dense part of Pluto’s surface,and thus a concentration of mass[mæs] 质量, it would affect Pluto’s orientation with respect to its moon. That would cause Pluto to topple['tɒp(ə)l]倾倒 over until Sputnik Planitia lay atone[ə'təʊn]弥补 of the two points at which the tidal axis intersects[ɪntə'sekt]相交 its surface. Unfortunately, basins are characterised以......为特征 by the absence of mass rather than its presence. But Dr Nimmo is unfazed[,ʌn'feɪzd]不苦恼的. He suggests that the huge quantities of material blasted out by the impact which created Sputnik Planitia would have reduced the pressure on Pluto’s crust[krʌst] 地表, letting the subterranean[,sʌbtə'reɪnɪən]地下的 water of a hypothetical[ˌhaɪpəˈθetɪkl]假想的ocean bulge[bʌldʒ]凸出closer to the surface. Since water is denser than most of the stuff found at or near Pluto’s surface, that upwelling 上升流would have increased the relative mass of Sputnik Planitia rather than decreasing it. Though speculative['spekjʊlətɪv]推测的, this idea is plausible['plɔːzɪb(ə)l]貌似可信的. Water is common in the Kuiper belt,and Pluto in particular is thought to consist of a rocky core岩核 overlain[,əuvə'lein]放在......上面 by a thick mantle['mænt(ə)l]覆盖of ice. That rocky core will contain radio active有辐射的 elements, the decay[dɪ'keɪ]衰减 of which might provide enough heat to melt some of the mantle. Add a dash[dæʃ]冲撞 of ammonia[əˈməʊniə]氨气, also common on Pluto, to lower the water’s freezing point, and Presto['prestəʊ]转眼间! You have an ocean. 歌曲:Fuckin' perfect----P!nk