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2009年9月的重大科学新闻当属证实了月球上存在水。这些水并不仅仅位于两极环形山的阴影中,而是到处都有。月球上有水,这肯定是爆炸性的.不是吗?不见得。意料之外的发现总是让人感兴趣,但这条新闻对于空间探测来说其实是一个坏消息:如果月球上的水并不是如此普遍地存在,也许会更好。 相似文献
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南极-艾肯盆地Th异常的富集特征和机理 总被引:1,自引:0,他引:1
遥感探测表明月表Th元素分布存在全球不均衡性,形成分别以雨海-风暴洋和南极-艾肯(SPA)盆地为中心的Th异常区.研究认为雨海-风暴洋的Th主要来源于对其下覆KREEP物质的开掘,但对SPA盆地的Th来源有各种不同的认识.本文通过对SPA盆地的地形、盆地构造、撞击坑分布、火山作用和地球化学特征的分析,以及对Th富集机理的探讨,认为SPA盆地内Th更可能来源于撞击作用对富Th下月壳物质的开掘;Th的弧形富集特征与盆地构造有很大相关性,并可能受到Apollo盆地形成的影响. 相似文献
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TheMarsroverSpiritissettobeginitsexplo-rationoftheredplanet,havingsuccessfullyrolledoutontotheMartiansurfaceThursdaymorning.Itsfirsttargetisanamelesscraterthatliesabout250metresnortheastofthelandingsite.Thedepression,createdbyameteorimpact,shouldhaveexposedrockthatisolderandmorepristinethanthatinthelargerGusevcraterthatSpiritlandedin.ScientistshopeitwillcontainmineralsthatprovewateroncefilledGusev-thefirststepinthesearchforlifeonMars.“We'llbecarefulasweapproach,”saysSteveSquyresofCornel… 相似文献
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The object-oriented approach is a powerful method in making classification. With the segmentation of images to objects, many features can be calculated based on the objects so that the targets can be distinguished. However, this method has not been applied to lunar study. In this paper we attempt to apply this method to detecting lunar craters with promising results. Craters are the most obvious fea- tures on the moon and they are important for lunar geologic study. One of the important questions in lunar research is to estimate lunar surface ages by examination of crater density per unit area. Hence, proper detection of lunar craters is necessary. Manual crater identification is inefficient, and a more efficient and effective method is needed. This paper describes an object-oriented method to detect lunar craters using lunar reflectance images. In the method, many objects were first segmented from the image based on size, shape, color, and the weights to every layer. Then the feature of "contrast to neighbor objects" was selected to identify craters from the lunar image. In the next step, by merging the adjacent objects belonging to the same class, almost every crater can be taken as an independent object except several very big craters in the study area. To remove the crater rays diagnosed as craters, the feature of "length/width" was further used with suitable parameters to finish recognizing craters. Finally, the result was exported to ArcGIS for manual modification to those big craters and the number of craters was acquired. 相似文献