New clues to Mars: Perseverance discovers strange rocks, and Curiosity finds large organic molecules to provide a basis for exploring ancient life.

On the vast Red Planet, two NASA rovers the size of a small car, Perseverance and Curiosity, are working tirelessly in different areas to find evidence that this now-barren planet may have once had a suitable environment for life. Scientists are convinced that the unique geological structure of Mars may contain key clues to solving the mystery of ancient life. As a result, these remotely controlled robotic explorers are traversing the rugged surface one step at a time, carefully collecting fascinating rock samples.

Just last month, the two Martian messengers made exciting new discoveries that further point to the speculation that life may have existed on Mars in ancient times.

Perseverance is still on an early exploration mission on the edge of the Jezero crater, where it landed four years ago. Not long ago, it came across a strange rock whose surface was covered with hundreds of tiny spheres of millimeters. The rock, which the team named "St. Pauls Bay", has a unique composition, with small, dark gray spheres ranging from elongated to angular and even tiny pinhole-like depressions. The discovery was first recorded on 11/0, and ten days later, NASA released the composite images taken by Perseverance's SuperCam long-range microimager. NASA scientists are working hard to unravel the mystery of the origin of these mysterious spheres.

In fact, Mars probes have previously discovered similar spherical structures. For example, both Curiosity that is still active and Opportunities that have "retired" have had similar records. Just a few months ago, Perseverance himself observed popcorn-like textures in the sedimentary rocks of Jezero Crater. In past cases, scientists have tended to think that these spheres are the product of groundwater interactions circulating in rock pores.

However, the discovery of the "St. Pauls Bay" rock appears to be unusual, and initial observations suggest that it may not have been generated in situ. Scientists theorize that the rock may be related to a dark layer of rock observed from space by the Mars Reconnaissance Orbiter. "Analyzing these geological features in the context in which they were formed will be critical to understanding their origins and their significance to the geological evolution history of the Jezero crater rim and beyond," NASA stressed in a press release. ”

Eyes turn to another highly decorated rover, Curiosity. It is being explored in an area about 2300 miles away from Perseverance. Recently, Curiosity scientists re-analyzed a rock sample collected earlier and named "Cumberland" and made a breakthrough. Through remote analysis of rock powder inside the rover, they discovered the largest organic compound ever found on Mars.

The findings were published in the Proceedings of the National Academy of Sciences on 24/0. Scientists believe that these large organic compounds are likely fatty acid fragments preserved in the sample. NASA notes that fatty acids are one of the basic chemical units of life on Earth. Of course, fatty acids are not exclusive to life, they can also be produced naturally through chemical reactions triggered by specific geological processes. But regardless of the exact source, this discovery is undoubtedly extremely exciting for the Curiosity team. "Curiosity scientists have previously discovered small, simple-structure organic molecules on Mars," NASA said in a statement, "and these larger, more complex compounds are the first to provide evidence that organic chemical processes on Mars may have advanced to the level of sophistication necessary to produce life." ”

回顧這兩位火星探險家的旅程：Perseverance 於2020年7月啟程，經歷了長達200天、跨越3億英里的漫漫征程，最終在2021年2月成功降落在 Jezero 隕石坑。在近四年的時間里，它搜尋並採集了超過二十份岩石樣本，其中許多已被精心存放在人類於其他星球建立的第一個樣本緩存點，等待未來任務將其帶回地球。Jezero 隕石坑底部，據信形成於約39億年前的一次劇烈撞擊，一直被視為尋找火星古老生命跡象的黃金地帶。在坑底探索多年後，Perseverance 於去年12月成功攀登上了隕石坑的陡峭邊緣，開啟了探索隕石坑邊緣地帶的新征程。

與此同時，Curiosity 早已是火星上的“老兵”。它於2012年8月登陸 Gale 隕石坑，一個據信形成於37億年前的區域。自那時起，它利用機械臂末端的鑽頭，已經成功採集並分析了42份岩石粉末樣本。這次發現大型有機分子的 “Cumberland” 樣本，便是2013年5月從 Gale 隕石坑內一個名為 “Yellowknife Bay” 的淺窪地精心鑽取的。當時，科學家們對 “Yellowknife Bay” 這個酷似古老湖床的地貌產生了濃厚興趣，甚至在指揮 Curiosity 前往其主要目標——從隕石坑中心高聳的 Mount Sharp——之前，特意安排它先對 “Yellowknife Bay” 進行了探訪。這次“節外生枝”的探索被證明極具價值。NASA 表示，分析顯示 “Cumberland” 岩石富含關於 Gale 隕石坑地質歷史的寶貴資訊，其中不僅包含了通常在水環境中形成的粘土礦物，還發現了能夠有效保存有機分子的硫元素，以及其他對生物過程至關重要的分子。

While Perseverance and Curiosity's relentless exploration has shed a light on the mysterious geology of Mars, it may be just the tip of the iceberg compared to what can be revealed in the future when samples are brought back to Earth for detailed study using the most cutting-edge lab equipment on Earth. NASA is currently actively planning a grand Mars sample return mission, and looks forward to bringing these precious "Martian visitors" back to their home park for more in-depth analysis in the next few years.

As Daniel Glavin, a senior scientist at NASA's Goddard Space Flight Center, puts it, "We are ready to take this critical next step in bringing Martian samples back to our lab, and hopefully finally unravel the long-running mystery of whether there is life on Mars." ”

This article was translated from floridatoday and edited by BALI.