Solar activity rises and falls on a regular cycle of about 11 years.

太阳的活跃程度按照一个11年代周期涨落。

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While solar activity is currently increasing in its standard 11-year cycle, this same cycle has occurred over millennia.

虽然，太阳活动目前在其标准的11年周期中逐渐增加，这种固定的周期持续了几千年。

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The sun is currently approaching what's known as solar maximum, the peak of our star's roughly 11-year cycle of magnetic activity.

因为目前的太阳正逐渐接近它的“活动峰年”，也就是周期约为11年的地磁活跃高峰期。

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The northern lights have been particularly spectacular in 2013 as the sun is expected to reach the peak of its 11-year solar cycle later this year.

CNN: Northern lights dazzle Northern Hemisphere

The sun is currently in an active phase of its 11-year solar cycle, and it should continue to fire off big storms for a while yet.

MSN: Amazing video captures magical-looking sun storm

The data, from NASA's TIMED mission, show that Earth's thermosphere (the layer above 62 miles or 100 km above the Earth's surface) "responds quite dramatically to the effects of the 11-year solar cycle, " Stan Solomon of the National Center for Atmospheric Research in Boulder, Colo.

MSN: Earth's upper atmosphere cooling dramatically