The space-weather forecast for the next few years: solar storms, with a chance of catastrophic blackouts on Earth. Are we prepared?
An X-class flare, the most powerful in NOAA’s classification system, overloads a sensor on the Solar Dynamics Observatory. With the solar cycle expected to peak in 2013, more flares and coronal mass ejections (CMEs) may be headed earthward. Photograph by NASA SDO, August 9, 2011 / National Geographic
The seething turmoil in our sun’s atmosphere is captured in extreme ultraviolet light by NASA’s Solar Dynamics Observatory (SDO), launched in 2010 to better understand solar activity and its impact on Earth. In this colorized view (NASA color-codes SDO images to represent different wavelengths of light), bright coronal loops arc between regions of intense magnetic activity, while cooler, darker filaments hang suspended in the sun’s magnetic field.
An aurora flutters above the Sommarøy bridge on the island of Kvaløy in northern Norway during a week of intense solar activity. Auroras appear when charged solar particles strike atmospheric gases, lighting them up like neon in a tube. Most common near the Poles, auroras also occur in lower latitudes during strong solar storms.
The Solar Dynamics Observatory captured a coronal mass ejection (at four o’clock in this and the following two images) using different wavelengths of light that reflect temperatures in layers of the sun’s atmosphere. Temperatures in the relatively cool chromosphere (above) are a mere 90,000 degrees Fahrenheit.
Why the sun’s atmosphere gets hotter farther from its surface remains a mystery. Regions of the corona can rise to more than ten million degrees during solar eruptions.
source National Geographic
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