哈葛尔沙丘场

哈葛尔沙丘场(Hagal)是火星北极高原下方一处沙丘场的非正式名称[1][2] ,其名字来源于弗兰克·赫伯特小说《沙丘》中虚构的哈葛尔星球[2]。它的中心坐标位于北纬78.0度、东经84度处,由带东南向背风面的线形和圆形沙丘组成[2]。它是火星勘测轨道飞行器高分辨率成像科学设备相机在季节性探索[2]的第三年(火星31年)[3],以每六周一次的速率进行成像的目标沙丘之一。由于该沙丘呈直线和圆形,具有点、杠的外观,因此也被称为“火星莫尔斯密码”[1][4][5][6]

哈葛尔沙丘场黑白图像,投影地图,带距离比例尺。

形成

虽然通常可从沙丘的走向和形状获得有关风向的信息,但由于哈葛尔沙丘形状复杂,所以很难确定所形成的风向。在该沙丘场情况中,理论上认为可能是陨石撞击在地面形成装满沙子的局部陨坑,减少了形成沙丘的沙子数量;反过来这又会影响当地的地形,导致风向发生变化[1][4]

美国宇航局关于火星摩尔斯电码的视频剪辑。

线形沙丘(横杠)是通过垂直于沙丘线的双向风产生出漏斗效应,引导沙子沿沙丘线性轴堆积而成;而当导致线性堆积的风被阻断时,则就形成了圆形沙丘(圆点),圆形沙丘被归类为“新月形沙丘”。然而,这两种结构的确切形成机制仍不清楚,这也是高分辨率成像科学设备任务选择该区域进行成像的原因[4]

高分辨率成像科学设备相机定位专家维罗妮卡·布雷(Veronica Bray)评论说,火星上的其他地方也有类似形状的沙丘,但由于其地形的罕见特征,哈葛尔沙丘场提供了更好的图像。布雷还将沙丘的分布结构“莫尔斯码”解码为“NEE NED ZB 6TNN DEIBEDH SIEFI EBEEE SSIEI ESEE SEEE!!”[7][8]

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参考文献

  1. ^ 1.0 1.1 1.2 Jeffrey Kluger. Here's What Explains the 'Morse Code' on Mars. Time magazine. 12 July 2016 [2022-04-05]. (原始内容存档于2021-11-26). 
  2. ^ 2.0 2.1 2.2 2.3 C.J. Hansen; S. Byrne; G. Portyankina; M. Bourke; C. Dundas; A. McEwen; M. Mellon; A. Pommerol; N. Thomas. Observations of the northern seasonal polar cap on Mars: I. Spring sublimation activity and processes (PDF). Icarus. 2013, (225): 881–897 [19 July 2017]. (原始内容存档 (PDF)于2022-02-01). Please see note at Table 1 page 883: Table 1 Sites imaged systematically by HiRISE in study year 3 (MY31) of seasonal campaign. The names are informal, some based on the sand dunes in the science fiction book Dune. 
  3. ^ Colin M. Dundas; Shane Byrne; Alfred S. McEwen; Michael T. Mellon; Megan R. Kennedy; Ingrid J. Daubar; Lee Saper. HiRISE observations of new impact craters exposing Martian ground ice. Journal of Geophysical Research. 27 January 2014, 119 (1): 109. Bibcode:2014JGRE..119..109D. doi:10.1002/2013JE004482. Six sites were discovered in the northern summer of Mars Year 29 (MY29), seven in MY30, and seven in MY31. (MY refers to the Mars calendar of Clancy et al. [2000], and this notation will be used throughout this paper; years begin at LS = 0°, the beginning of northern spring. MY32 began on 31 July 2013.) 
  4. ^ 4.0 4.1 4.2 Martian Morse Code. NASA. 8 July 2016 [2022-04-05]. (原始内容存档于2022-03-31). 
  5. ^ Martian Morse Code ESP_045334_2580. HiRISE. 29 June 2016 [2022-04-05]. (原始内容存档于2021-10-22). 
  6. ^ Jessica F. Morse Code in Sand Dunes Found on Mars?. Nature World News. 12 July 2016 [2022-04-05]. (原始内容存档于2020-01-06). NASA calls the formation the "Martian Morse Code," 
  7. ^ Maddie Stone. There's a Secret Message Written Into the Sands of Mars. Gizmodo. 8 July 2016 [2022-04-05]. (原始内容存档于2022-04-09). 
  8. ^ Doug Criss. Message from Mars? Morse code dunes found on red planet. CNN. 13 July 2016 [2022-04-05]. (原始内容存档于2022-04-05). 

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