Although the sun's current 11-year cycle of activity is one of the quietest ever recorded, this Oct. 20 image (left) is anything but calm. The composite combines different views of extreme ultraviolet light captured by NASA's space-based Solar Dynamics Observatory. The coronal loops -massive magnetic arches of hot gas -sizzle at 1.8 million degrees Fahrenheit (yellow), while plumes of plasma (red) simmer at a relatively cool 90,000 F. In October, the area known as active region 12192 (the bright patch on the left side of the main image) spawned the largest sunspot group in 24 years. According to NASA solar scientist C. Alex Young, the region is unusual because it produced fairly large solar flares but not the huge coronal mass ejections that typically occur at the same time, sometimes damaging satellites.
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机译：尽管太阳目前的11年活动周期是有记录以来最安静的周期之一，但这张10月20日的照片（左图）却完全平静。该复合材料结合了NASA太空基太阳动力学天文台捕获的极端紫外线的不同视图。冠状环-大量的热气-在180万华氏度（黄色）时嘶嘶作响，而等离子（红色）羽流则在相对凉爽的90,000华氏度下沸腾。10月，该区域称为活动区域12192（明亮的区域） （在主图像的左侧）产生了24年以来最大的黑子组。根据NASA太阳科学家C. Alex Young的说法，该地区是不寻常的，因为它产生了相当大的太阳耀斑，但没有产生通常同时发生的巨大日冕物质抛射，有时会损坏卫星。
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