1.古大西洋
2.亚皮特斯海
3.土卫八
1.a natural satellite of Saturn, discovered in 1671. It is 1,436 km (892 mi) in diameter and occupies an outer orbit.
1.If the outer layers of Iapetus froze solid at this time, some remnant of that shape might be preserved.
如果它的外层在此时凝固成固体，这个形状的残迹可能还能被保存下来。
2.Whatever the truth, the range is remarkable and makes Iapetus look like a walnut in space.
不管事实到底如何，这些山脉确实非常壮观，而且使得土卫八看起来像太空中的一个核桃。
3.EVEN a cursory glance at Saturn's moon Iapetus reveals it to be an oddball.
甚至只是对于土星的卫星土卫八粗略地一瞥，也足以表露出它的古怪。
4.The subsatellite would have spiraled slowly away from Iapetus until Saturn grabbed it.
子卫星缓慢地成螺旋形远离Iapetus直到其被土星捕获。
5.The other half of Iapetus is relatively bright but oddly covered with long and thin streaks of dark.
而另一半边的土卫八则是相对明亮但是怪异地布满又长又细的深色条纹。
6.In the 17th century, the astronomer Giovanni Cassini noticed Iapetus had one dark side and one lighter side, but had no idea why.
在17世纪，天文学家乔万尼·卡西尼（GiovanniCassini）发现“土卫八”一面暗一面亮，但他当时不知道其原因。
7.The ring circles in the same direction as Phoebe, while Iapetus, the other rings and most of Saturn's other moons go the opposite way.
光环和“土卫九”沿同一方向形成圈，而“土卫八”、其它光环以及土星的大多数其它卫星沿相反方向运动。
8.And its flattened shape implies that Iapetus once spun very quickly, completing a rotation in 16 hours.
并且它平坦的外形意味着其曾经旋转的很快，完成一个自转周期为16小时。
9.A sub-satellite of the Saturnian moon would explain two of the most puzzling features of Iapetus.
土星卫星的子卫星将解释Iapetus的两个最使人迷惑的特征。
10.Possibly solving a 300-year-old mystery, two recent studies suggest a likely mechanism behind Iapetus' two-faced nature.
最近的两个研究可能能解释伊阿珀托斯两面性的产生机理，解决这个300年之久的谜题。