加载中…美国国家航空航天局观察到火星上的“雪花”
(2012-09-14 10:48:24)
标签：
南极二氧化碳轨道飞行器雪花火星上杂谈 |
分类： 科学与技术 |
http://photos.state.gov/libraries/amgov/3234/week_2/09122012_pia16138-640_jpg_600.jpg
来自美国国家航空航天局（NASA）火星勘测轨道飞行器的数据证实火星上有二氧化碳雪花积聚。这是迄今为止太阳系中有二氧化碳雪花积聚的唯一已知例证。
来自美国国家航空航天局（NASA）火星勘测轨道飞行器（Mars Reconnaissance Orbiter）的数据为科学家们提供了迄今为止最明确的证据，证实火星上有二氧化碳雪花积聚。这是迄今为止太阳系中有二氧化碳雪花积聚的唯一已知例证。
二氧化碳（通常称为“干冰”）大约在摄氏零下125度时“结冰”，远低于水结冰的气温。二氧化碳雪花提醒科学家，虽然火星的某些区域看起来与地球相似，其实这个红色行星与地球差异很大。这一探测结果发表于《地球物理研究期刊》（Journal of Geophysical Research）。
该研究报告的第一作者 保罗·海恩（Paul Hayne）说：“这是第一次确切地探测到二氧化碳雪云。我们有足够证据表明这些雪云由二氧化碳构成——即火星空气构成的‘雪花’——这些雪花有足够的厚度，能够在飘落后积聚在火星表面。”海恩是位于加利福尼亚州帕萨迪纳（Pasadena, California）的美国国家航空航天局喷气推进实验室（Jet Propulsion Laborator）的研究人员。
上图显示了火星南极极冠（polar cap）部位的“积雪”，即小颗粒二氧化碳结成的冰。这是火星勘测轨道飞行器利用红外线测量的结果。
关于火星“雪花”的详细信息，请查阅美国国家航空航天局发布的新闻稿（英文）。
Read more: http://iipdigital.usembassy.gov/st/chinese/inbrief/2012/09/20120913135946.html#ixzz26POYSnpv
NASA Observations Point to “Dry Ice” Snowfall on Mars
http://photos.state.gov/libraries/amgov/3234/week_2/09122012_pia16138-640_jpg_600.jpg
Data from NASA’s Mars Reconnaissance Orbiter have given scientists the clearest evidence yet of carbon-dioxide snowfalls on Mars.
Data from NASA’s Mars Reconnaissance Orbiter have given scientists the clearest evidence yet of carbon-dioxide snowfalls on Mars. This reveals the only known example of carbon-dioxide snow falling anywhere in the solar system.
Frozen carbon dioxide, better known as “dry ice,” requires temperatures of about minus 125 degrees Celsius, which is much colder than needed for freezing water. Carbon-dioxide snow reminds scientists that although some parts of Mars may look quite Earth-like, the Red Planet is very different. The report is being published in the Journal of Geophysical Research.
“These are the first definitive detections of carbon-dioxide snow clouds,” said the report’s lead author, Paul Hayne of NASA’s Jet Propulsion Laboratory in Pasadena, California. “We firmly establish the clouds are composed of carbon dioxide — flakes of Martian air — and they are thick enough to result in snowfall accumulation at the surface.”
This map shows the distribution of small-grain carbon-dioxide ice deposits formed by snowfall over the south polar cap of Mars. It is based on infrared measurements by the Mars Reconnaissance Orbiter.
For more on the Martian snowfall, see the NASA press release.
Read more: http://iipdigital.usembassy.gov/st/english/inbrief/2012/09/20120912135841.html#ixzz26POZrkz5
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