NASA SDO: Largest Sunspot in 24 Years Mystifies Scientists

The Jupiter-sized sunspot AR 12192 is the largest active region seen on the sun in 24 years. 

Credit: NASA SDO

The biggest sunspot to grace the face of the sun in more than two decades just rotated out of Earth's view, but it was responsible for kicking up some truly amazing solar activity this week.

The sunspot (called Active Region 12192 or AR 2192) shot off four powerful flares in four days recently, with many more smaller flares sprinkled in as well.

The sunspot region was about the size of the planet Jupiter and is the largest solar flare observed in 24 years.

AR 2192 was actually one of the biggest observed sunspots of all time, ranking 33rd largest of 32,908 active regions since 1874, according to NASA scientists C. Alex Young and Dean Pesnell. But how does a sunspot grow this big?

"The simple answer is we really don't know," Young told reporters.

"Being close to solar maximum [the peak in the sun's 11-year solar cycle] means there is more concentrated magnetic field and magnetic energy under the solar surface waiting to bubble up, but the question of why it comes up as one spot instead of two or more is really still unknown, a mystery."

"I guess a good analogy is when you twist a rubber band or piece of string," Young added. "Why do, say, three knots or bunches form instead of two or four?"

"The physics is probably too complicated for us at this point but we can get a handle on, say, when the knots will start to form once we better understand the properties of the rubber band or string and how much twist we put into them. We are not to that point with the sun but we may get there eventually."

The largest sunspot since November 1990 is seen traveling across the front of the sun in these images from NASA's SDO, captured Oct. 17-Oct 29, 2014.

Image Credit: NASA/SDO

Sunspots are active areas on the sun. They generally form when magnetic field lines are warped, and if they become twisted.

Part of it may break out, and show up on the face of the star. Sunspots look dark because they are cooler than the area surrounding them.

This sunspot is particularly special because of the somewhat strange way scientists have seen it behave.



Instead of shooting out huge bursts of plasma, called coronal mass ejections (CMEs), with powerful flares, the giant sunspot hasn't produced significant CMEs during its time rotating in view of Earth, according to Young.

"What's really curious about it [the large sunspot] is that it's produced so many flares of pretty good size, but little or no coronal mass ejections," Young said.

"It's not that it's never happened before, but it tends to be the case that when you have a big flare, you generally get a big CME."

Earth-directed CMEs are responsible for geomagnetic storms that can harm satellites in orbit or even knock out power grids on the planet.

A CME produced by a sunspot larger than AR 2192 knocked out the power in Quebec, Canada, in 1989, Young said.

The sunspot just rotated out of view of Earth, according to Spaceweather.com, but that doesn't necessarily mean that AR 2192 won't make another appearance on Earth's side of the star.

NASA IRIS Mission: X-Flare - Close-up of Sunspot - Video

NASA's Interface Region Imaging Spectrograph (IRIS) mission can only study small areas of the Sun's surface at a time.

This week’s mission planner pointed the probe at promising sunspot AR2158 just in time for an X1.6-class flare.

Searing plasma "lines" spark and shift at several hundred miles per hour during the flare.



Sun Unleashes Major Solar Flare at Earth.

A coronal mass ejection burst off the side of the sun on May 9, 2014. The giant sheet of solar material erupting was the first CME seen by NASA's Interface Region Imaging Spectrograph (IRIS).

The field of view seen here is about five Earth's wide and about seven and a half Earth's tall.

NASA's Solar Dynamics Observatory (SDO): Massive Sunspot AR1944

One of the largest sunspots in the last nine years, labeled AR1944, was seen in early January 2014, as captured by NASA's Solar Dynamics Observatory (SDO). 

An image of Earth has been added for scale. 

Credit: NASA/SDO

An enormous sunspot, labeled AR1944, slipped into view over the sun's left horizon late on Jan. 1, 2014.

The sunspot steadily moved toward the right, along with the rotation of the sun, and now sits almost dead center, as seen in the image above from NASA's Solar Dynamics Observatory (SDO).

Sunspots are dark areas on the sun's surface that contain complex arrangements of strong magnetic fields that are constantly shifting.

The largest dark spot in this configuration is approximately two Earths wide, and the entire sunspot group is some seven Earths across.

For comparison, another giant sunspot, five to six Earths across, is shown below from 2005. The image was captured by the European Space Agency and NASA's Solar and Heliospheric Observatory (SOHO).

Sunspots are part of what's known as active regions, which also include regions of the sun's atmosphere, the corona, hovering above the sunspots.

Active regions can be the source of some of the sun's great explosions: solar flares that send out giant bursts of light and radiation due to the release of magnetic energy, or coronal mass ejections that send huge clouds of solar material out into space.

As the sunspot group continues its journey across the face of the sun, scientists will watch how it changes and evolves to learn more about how these convoluted magnetic fields can cause space weather events that can affect space-borne systems and technological infrastructure on Earth.

Two of the largest sunspots in the last nine years: the one on the left is from Jan. 17, 2005, captured by ESA/NASA's Solar Heliospheric Observatory; the one on the right is from Jan. 7, 2014, captured by NASA's Solar Dynamics Observatory. 

Credit: ESA/NASA SOHO and NASA SDO

NASA SDO: Sunspots and Solar Flare March 13th 2012

Image Credit: NASA/SDO 

Watch the Video of the event here

NASA's Solar Dynamics Observatory (SDO) captured this image of an M7.9 class flare on March 13, 2012 at 1:29 p.m. EDT.

It is shown here in the 131 Angstrom wavelength, a wavelength particularly good for seeing solar flares and a wavelength that is typically colourised in teal.

The flare peaked at 1:41 p.m. EDT. It was from the same active region, No. 1429, that produced flares and coronal mass ejections the entire week.

The region has been moving across the face of the sun since March 2, and will soon rotate out of Earth view.

A solar flare is an intense burst of radiation coming from the release of magnetic energy associated with sunspots.

Flares are our solar system’s largest explosive events. They are seen as bright areas on the sun and last from mere minutes to several hours.

Scientists classify solar flares according to their x-ray brightness. There are 3 categories: X-, M- and C-class.

• X-class flares are the largest of these events.
• M-class flares are medium-sized; they can cause brief radio blackouts that affect Earth's polar regions.
• C-class flares are small with few noticeable consequences on Earth, compared to X- and M-class.

NASA SDO: Solar Storms Building Toward Peak in 2013

This image from the Solar Dynamics Observatory shows the X6.9 solar flare of Aug. 9, 2011 near the western limb (right edge) of the sun. CREDIT: NASA/SDO/Weather.com

Solar flares like the huge one that erupted on the sun early on Aug. 9, will only become more common as our sun nears its maximum level of activity in 2013, NASA scientists say.

Tuesday's flare was the most powerful sun storm since 2006, and was rated an X6.9 on the three-class scale for solar storms (X-Class is strongest, with M-Class in the middle and C-Class being the weakest).

Flares such as this one could become the norm soon, though, as our sun's 11-year cycle of magnetic activity ramps up, scientists explained.

The sun is just coming out of a lull, and scientists expect the next peak of activity in 2013. The current cycle, called Solar Cycle 24, began in 2008.

Sun Spot activity renewed

Two sunspots are visible on our star’s face for the first time in more than a year, possibly ending an unexpected lull in solar activity.

Solar flares rise and fall on an 11-year cycle, so scientists thought sunspot activity would pick up some time in 2008. It didn’t. And this year has been quiet, too. No sunspots have been visible on the sun for 80 percent of the days this year.

Sunspot activity is correlated with the total amount of energy we receive from the sun. If the sun’s activity were to change remarkably, it would have an influence on global climate. So, in the context of climate change, the fact that the current solar minimum has been the longest and deepest in more than a century has been of special interest.

In May, a big sunspot seemed to augur a return to normal, but it faded away and sunspotless days returned. The latest activity might not mark the end of the solar minimum, however. People have been counting sunspots since Galileo first observed one in the early 17th century. Through the 28 documented cycles, stretching from 1745 to today, some variation in cycle length has been observed.

That’s why NASA’s former chief sunspot watcher, Michael Kaiser, told us earlier this year that the minimum was “not out of the extreme ordinary.”