June 11, 2014
Solar Max Has Arrived – But How Strong Will It Actually Be?
Brett Smith for redOrbit.com - Your Universe Online
Our Sun is constantly cycling between periods of low activity and high activity – known as solar minimum and solar maximum, or Solar Max, respectively.
In 2008 and 2009, NASA’s solar experts reported they were surprised to see the Sun descend into one of its deepest solar minimums in recorded history. But now, NASA observers are saying that the solar minimum is almost over.
[ Watch the Video: ScienceCasts: Solar Mini-Max ]
Although many academic sources describe the solar maximums and solar minimums as an ’11-year cycle,’ data has shown the cycle takes anywhere from 9 to 14 years. One Solar Max in the 17th century actually took 70 years to complete.
Pesnell cited several observations in calling the start of a new Solar Max.
"The sun's magnetic field has flipped; we are starting to see the development of long coronal holes; and, oh yes, sunspot counts are cresting,” Pesnell said.
"Solar Maximum is here … Finally,” added Doug Bieseker of the NOAA Space Weather Prediction Center and a panelist, along with Pesnell, on the NOAA/NASA Solar Cycle Prediction Panel.
The panelists are also in agreement that the new Solar Max isn’t one of the strongest on record.
"This solar cycle continues to rank among the weakest on record," said Ron Turner of Analytic Services, a senior science advisor to NASA's Innovative Advanced Concepts program.
Turner created a graph of the current “Cycle 24” against the previous 23 cycles that date back to 1755.
"In the historical record, there are only a few Solar Maxima weaker than this one,” Turner said.
As a result of the extraordinarily weak solar cycle, researchers have dubbed this maximum a “Mini-Max.”
"Solar Cycle 24, such as it is, will probably start fading by 2015,” Pesnell said.
The researchers noted that events like this upcoming transitional period are known for causing some of the most violent solar activity. According to Bieseker, historical accounts of solar activity indicate that most strong solar flares and noteworthy geomagnetic storms normally take place in the falling phase of solar cycles. In fact, this cycle has already unleashed one of the most powerful storms in recorded history.
On July 23, 2012, a plasma cloud or "CME" fired off from the sun at speeds of around 1,800 miles per second, more than four times faster than a standard eruption. While the storm ripped through Earth orbit, we weren't there. The CME did hit NASA's STEREO-A spacecraft, which recorded the phenomenon. Scientists said the event was as powerful as the iconic Carrington Event of 1859, which set telegraph offices on fire and caused the Northern Lights to be as visible as far south as Hawaii. If the 2012 CME had hit Earth, the damage to power grids and satellites would have been considerable, NASA scientists said.
With the 2012 event still relatively fresh and historical records showing we’re in for heavy solar activity, Pesnell called for vigilance.
"We're not out of the woods yet," he said.
SHOP NOW: Magnetohydrodynamics of the Sun