月球？水星！“貝比科隆博號”探測器掠過水星拍下震撼照片！

Which part of the Moon is this? No part -- because this is the planet Mercury. Mercury's old surface is heavily cratered like that of Earth's Moon. Mercury, while only slightly larger than Luna, is much denser and more massive than any Solar System moon because it is made mostly of iron. In fact, our Earth is the only planet more dense. Because Mercury rotates exactly three times for every two orbits around the Sun, and because Mercury's orbit is so elliptical, visitors on Mercury could see the Sun rise, stop in the sky, go back toward the rising horizon, stop again, and then set quickly over the other horizon. From Earth, Mercury's proximity to the Sun causes it to be visible only for a short time just after sunset or just before sunrise. The featured image was captured last week by ESA and JAXA's passing BepiColombo spacecraft as it sheds energy and prepares to orbit the innermost planet starting in 2025.?

這是月球的哪一部分？哪都不是，因為這是水星。水星古老的表面像月球一樣布滿了撞擊坑。水星雖然只比月亮略大，但它比太陽系任何一顆衛(wèi)星的密度都要高得多，質(zhì)量也更大，因為它主要是由鐵構(gòu)成的。事實上，在行星里，也只有我們的地球比它密度更高。水星很精確的每繞太陽公轉(zhuǎn)兩圈就自轉(zhuǎn)三圈，而且水星的軌道非常橢圓，所以水星上的游客可以看到太陽升起，在天空中停留，然后竟然向升起處的地平線返回，并再次停留，最后向另一側(cè)的地平線快速落下。從地球上看，水星與太陽在天空中總是離得很近，所以只能在日落后或日出前很短時間內(nèi)才能看到。上周，歐洲空間局（ESA）和日本航天局（JAXA）的“貝比科隆博號”探測器掠過了這顆最內(nèi)側(cè)行星，拍攝了這張?zhí)厣掌Ｔ撎綔y器計劃從2025年開始環(huán)繞水星運行。