蓝色的告别

A blue halo glows around Pluto’s receding crescent in this parting image taken by NASA’s New Horizons spacecraft on July 14, 2015. At the time of this shot, New Horizons was 120,000 miles (200,000 kilometers) away from Pluto.

Shown in approximate true color, the picture was constructed from a mosaic of six black-and-white images from the Long Range Reconnaissance Imager, with color added from a lower resolution Ralph/Multispectral Visible Imaging Camera color image.

Scientists believe the haze is a smog resulting from the action of sunlight on methane and other molecules in Pluto’s atmosphere. This reaction produces a complex mixture of hydrocarbons that accumulate into small haze particles which scatter blue light. As they settle down through the atmosphere, the haze particles form numerous intricate horizontal layers that extend to altitudes of over 120 miles (200 kilometers).

Image Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute

2015年7月14日，NASA的新视野号飞船拍摄的这张临别照片中，蓝色的光环围绕着后退的月牙形冥王星发光。拍摄时，新视野号距离冥王星12万英里（20万公里）。

这张照片以近似真实的颜色显示，由来自远程侦察成像仪的六幅黑白图像拼接而成，并从低分辨率Ralph/多光谱可见成像相机彩色图像中添加了颜色。

科学家们认为，这种雾霾是太阳光对冥王星大气中甲烷和其他分子的作用产生的烟雾。这一反应产生一种复杂的碳氢化合物混合物，这些碳氢化合物聚集成细小的雾霾颗粒，从而散射蓝光。当雾霾颗粒在大气中沉降时，形成了许多复杂的水平层，延伸到超过120英里（200公里）的高度。

图片来源：NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute