丘格彗星上的一公里高悬崖

丘格彗星上的一公里高悬崖

A Kilometer High Cliff on Comet Churyumov – Gerasimenko
Image Credit & Licence (CC BY-SA 3.0 IGO): ESA, Rosetta spacecraft, NAVCAM; Additional Processing: Stuart Atkinson

Explanation: This kilometer high cliff occurs on the surface of a comet. It was discovered on the dark nucleus of Comet Churyumov – Gerasimenko (CG) by Rosetta, a robotic spacecraft launched by ESA, which orbited the comet from 2014 to 2016. The ragged cliff, as featured here, was imaged by Rosetta early in its mission. Although towering about one kilometer high, the low surface gravity of Comet CG would likely make a jump from the cliffs by a human survivable. At the foot of the cliffs is relatively smooth terrain dotted with boulders as large as 20 meters across. Data from Rosetta indicates that the ice in Comet CG has a significantly different deuterium fraction — and hence likely a different origin — than the water in Earth’s oceans. The probe was named after the Rosetta Stone, a rock slab featuring the same text written in three different languages that helped humanity decipher ancient Egyptian writing.

Tomorrow’s picture: near to the heart

丘格彗星上的一公里高悬崖
影像提供与授权 (CC BY-SA 3.0 IGO): ESA, Rosetta spacecraft, NAVCAM; Additional Processing: Stuart Atkinson

说明: 这个1公里高的悬崖座落在彗星的表面上。它是由欧洲航天局（ESA）发射的无人航天器罗塞塔号，发现于丘格彗星（comet Churyumov-Gerasimenko，CG）的黝黑彗核上。罗塞塔号在2014年到2016年期间绕这颗彗星运行，而呈现这片崎岖悬崖的影像，则是由罗塞塔号摄于任务的初期。虽然悬崖的高度约为1公里，但由于丘格彗星的表面重力极低，从悬崖 跳下的人应该能存活。悬崖底部的原野相对平坦，上头散布的大圆石之直径可达20公尺。罗塞塔号回传的数据显示，丘格彗星水冰的氘含量与地球海洋的水差异颇大，显然二者的来源不同。罗塞塔号探测船是因罗塞塔石碑而得名，而这块刻着相同文稿的3种语言版本的石碑，对人类解读古埃及文字贡献了关键的助力。

明日的图片: near to the heart