之前你從來沒見過的火星：巨大的冰牆上顯示紅色星球的另一面
Mars as you've never seen it before: The colossal ice walls that show another side of the Red Planet
By Daily Mail Reporter
Last updated at 5:58 PM on 22nd March 2010
It looks like a filmmaker's apocalyptic vision of Earth following a devastating natural disaster.
它看起來像一個電影人的地球天啟景象，在毀滅性的自然災害後。
But this colossal ice formation is actually a portion of the wall terraces of a huge crater on Mars.
但這巨大的冰塊構成，實際上是火星上的一個巨大隕石坑的牆梯田的一部分。
Approximately 37 miles in diameter, a section of the Mojave Crater in the planet's Xanthe Terra region has been digitally mapped by Nasa scientists.
The result is this digital terrain model that was generated from a stereo pair of images and offers a synthesized, oblique view of a 2.5-mile portion of the crater's wall terraces.
Colossal: This ice formation is a portion of the wall terraces of the Mojave Crater on Mars. It has barely suffered any erosion so offers scientists a tantalising glimpse of what a very large complex crater looks like龐大：這冰的構成是火星上的莫哈韋隕石坑梯田牆的一部分，它沒有受到任何侵蝕，提供科學家們大略一瞥，一個非常大的複雜火山口看起來像甚麼
The sheer depth of the crater - about 1.6 miles - demonstrates that Mojave has experienced little infilling or erosion.
The result offers scientists a tantalising glimpse of what a very large complex crater looks like on Mars because it remains so fresh while most others - especially this size - have been affected by erosion, sedimentary infilling and overprinting by other geologic processes.
Such a fresh crater provides an insight into the impact process.
This view, in which the vertical dimension is exaggerated three-fold compared with horizontal dimensions, shows the ponding of material backed up behind massive wall-terrace blocks of bedrock.
Hundreds of impact craters on Mars have similarly ponded features with pitted surfaces. These 'pitted ponds' are thought to result when material melted by the crater-causing impacts is captured behind the wall terraces.
The portion of the Mojave Crater's north-western edge shown here spans about 2.5 miles in width halfway between the bottom and top of the image. The view is toward the north.
Mojave is one of the freshest large craters on Mars. A survey of its features indicates very few overprinting craters on them, and an analysis of that infrequency suggests the crater may be as young as about ten million years, very young for a crater of this size.
The fans and channels hint that impacts such as Mojave's may have unleashed water or water-ice from the subsurface to flow across the surface and, perhaps, condense as rain or snow for a brief period of Martian time.
This further suggests that early climate on Mars could have been heavily influenced by the intense bombardment about 3.9billion years ago when impacts creating craters Mojave's size and far larger were more common.
http://www.dailymail.co.uk/sciencetech/article-1259813/Mars-Ice-walls-Red-Planet.html
火星上的遠古湖可能有生命
火星有樹？
“機遇號”再傳喜訊 星球相撞暴露內核岩石
群芳
2010年01月27日10:33
來源：《科學時報》
美國宇航局（NASA）的機遇號火星探測器又為科學家帶來了一個驚喜。據美國《科學》雜志在線新聞報道，這塊名為“馬凱特島”的火星岩石（如上圖）與這部6輪機器人之前發現的其他任何石頭都不一樣。其紋理粗糙的結構表明它並非來自於行星表面，而是產自火星內核。過去的某一天，一顆巨大的天體——可能是小行星——與火星表面發生碰撞，從而使外殼內部的岩石裸露出來。在被拋向天空后，這塊籃球大小的岩石落在了子午平原——這裡正是機遇號6年來辛勤工作的地方。項目首席科學家Steve Squyres表示：“它來自距離這裡很遠的火星深處。但是究竟有多深、多遠，我們現在尚無法估計。”
（責任編輯：王太拓（實習））
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