36亿年的彩色蜡笔

The Pilbara in northwestern Australia exposes some of the oldest rocks on Earth, over 3.6 billion years old. The iron-rich rocks formed before the presence of atmospheric oxygen, and life itself. Found upon these rocks are 3.45 billion-year-old fossil stromatolites, colonies of microbial cyanobacteria. The image, acquired in October 2004, is a composite of ASTER bands 4-2-1 displayed in RGB.

With its 14 spectral bands from the visible to the thermal infrared wavelength region and its high spatial resolution of about 50 to 300 feet (15 to 90 meters), ASTER images Earth to map and monitor the changing surface of our planet and is one of five Earth-observing instruments launched Dec. 18, 1999, on the Terra satellite. The instrument was built by Japan’s Ministry of Economy, Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and data products.

The broad spectral coverage and high spectral resolution of ASTER provides scientists in numerous disciplines with critical information for surface mapping and monitoring of dynamic conditions and temporal change. Example applications are monitoring glacial advances and retreats; monitoring potentially active volcanoes; identifying crop stress; determining cloud morphology and physical properties; wetlands evaluation; thermal pollution monitoring; coral reef degradation; surface temperature mapping of soils and geology; and measuring surface heat balance.

Image Credit: NASA/METI/AIST/Japan Space Systems, and U.S./Japan ASTER Science Team

澳大利亚西北部的皮尔巴拉地区暴露出地球上最古老的岩石，这些岩石已有36亿年的历史。富含铁的岩石形成于大气中存在氧气和生命之前。在这些岩石上发现了34.5亿年前的叠层石化石，是微生物蓝藻的菌落。该图像拍摄于2004年10月，是ASTER波段4-2-1的合成图像，以RGB显示。

ASTER拥有从可见光到热红外波长范围的14个光谱带，其高空间分辨率约为50至300英尺（15至90米），对地球进行成像以绘制和监测我们星球不断变化的表面，是1999年12月18日在Terra卫星上发射的五个地球观测仪器之一。该仪器由日本经济产业省制造。美国/日本联合科学团队负责仪器和数据产品的验证和校准。

ASTER的广谱覆盖和高光谱分辨率为众多学科的科学家提供了地表测绘和动态条件和时间变化监测的关键信息。示例应用是监测冰川的形成和消退；监测潜在的活火山；识别作物压力；确定云的形态和物理性质；湿地评价；热污染监测；珊瑚礁退化；土壤和地质的地表温度绘图；并测量表面热平衡。

影像来源：NASA/METI/AIST/Japan Space Systems, and U.S./Japan ASTER Science Team