Solar cycle will be weakest since 1928
A panel of international experts has predicted that the Sun's new solar cycle, which is thought to have begun in December 2008, will be the weakest since 1928.india Updated: May 12, 2009 13:20 IST
A panel of international experts has predicted that the Sun's new solar cycle, which is thought to have begun in December 2008, will be the weakest since 1928.
Solar activity waxes and wanes every 11 years.
Cycles can vary widely in intensity, and there is no foolproof way to predict how the sun will behave in any given cycle.
In 2007, an international panel of 12 experts split evenly over whether the coming cycle of activity, dubbed Cycle 24, would be stronger or weaker than average.
The group did agree the sun would probably hit the lowest point in its activity in March 2008 before ramping up to a new cycle that would reach its maximum in late 2011 or mid-2012.
But, the sun did not bear out those predictions.
Instead, it entered an unexpectedly long lull in activity with few new sunspots. It is thought to have reached its minimum in December 2008, and now seems to be slowly waking up.
According to a report in
one such sign is two new active regions captured this week by the ultraviolet camera on one of NASA's twin STEREO probes.
"There's a lot of indicators that Cycle 24 is ready to burst out," said panel chair Doug Biesecker of the National Oceanic and Atmospheric Administration Space Weather Prediction Center in Boulder, Colorado.
The panel now expects the sun's activity will peak about a year late, in May 2013, when it will boast an average of 90 sunspots per day.
That is below average for solar cycles, making the coming peak the weakest since 1928, when an average of 78 sunspots was seen daily.
Sunspots are Earth-sized blotches that coincide with knotty magnetic fields. They are a common measure of solar activity.
The higher the number of sunspots, the higher the probability of a major storm that could wreak havoc on Earth.
A lower number of sunspots could mean space weather will be relatively mild in the coming years.