真实色彩的土卫二

2025年6月10日

Enceladus in True Color
Image Credit: NASA, ESA, JPL, SSI, Cassini Imaging Team

Explanation: Do oceans under the ice of Saturn’s moon Enceladus contain life? A reason to think so involves long features — some dubbed tiger stripes — that are known to be spewing ice from the moon’s icy interior into space. These surface cracks create clouds of fine ice particles over the moon’s South Pole and create Saturn‘s mysterious E-ring. Evidence for this has come from the robot Cassini spacecraft that orbited Saturn from 2004 to 2017. Pictured here, a high resolution image of Enceladus is shown in true color from a close flyby. The deep crevasses are partly shadowed. Why Enceladus is active remains a mystery, as the neighboring moon Mimas, approximately the same size, appears quite dead. A analysis of ejected ice grains has yielded evidence that complex organic molecules. These large carbon-rich molecules bolster — but do not prove — that oceans under Enceladus’ surface could contain life.

APOD Turns 30!: Free public lecture in Anchorage tomorrow (Wednesday) at 7 pm
Tomorrow’s picture: top 25

真实色彩的土卫二
影像提供: NASA, ESA, JPL, SSI, Cassini Imaging Team

说明: 土卫二（Enceladus）冰层下方的海洋里头有生命吗？我们之所以会如是想，是因为它表面名为虎纹的颀长表面结构，咸认是这颗卫星把内部寒冰喷到太空中的窗口。从这些表面裂缝喷出的微细冰粒，成为笼罩在土卫二南极的云团，并造就了土星神秘的E环。支持上述窗口说法的观测证据，来自2004年2017年间探测土星的卡西尼号探测器。而上面这幅土卫二的真色彩高解析影像，来自卡西尼号探测器的某次近距离飞越。影像中的部分深邃裂缝，沉浸在暗影里。然而，为何土卫二如此活跃，而邻近大小相近的卫星土卫一（Mimas），却是个死寂的天体？此外，针对喷出冰粒所进行的分析显示，它们带着复杂的有机分子。这些富含碳的分子，支持但并不能证明土卫二表面下的海洋有生命。