Nasa launched its Solar Dynamics Observatory successfully from Cape Canaveral today.
The timing – coinciding with the sun’s awakening from the longest quiet spell for a century – is perfect.
The SDO will observe variations in solar activity, to help scientists predict “space weather” better.
Violent bursts of activity, such as solar flares and “coronal mass ejections” (CMEs), can disrupt satellites, communications and power systems on Earth. And a good warning can reduce the damage.
The recent minimum in the 11-year solar cycle has lasted longer and been quieter than experts had expected. Over the past two years, more than 250 days have had no sunspots at all.
Some people were even speculating that the sun might be entering a period of inactivity lasting several decades, similar to the Maunder Minimum of the 17th century.
But the past month has seen a renewed burst of solar flares, suggesting that the cycle is on an upward curve toward a likely maximum in 2013.
Three instruments on the $850m SDO will be observing the workings of the solar dynamo, whose fluctuations are responsible for our space weather, over the next five years.
Margaret McCartney
Clive Cookson
Andrew Jack