A massive sunspot capable of knocking out communications and power is once again aligning with Earth.
Renamed Active Region 12192, because it is a sunspot that has come around a second time, it is due to come into alignment in a few days.
Sunspots of this kind spew solar flares that can create what’s called a coronal mass ejection, or CME, that flings hot bursts of millions of tons of highly charged particles into space at 4 million miles per hour.
If the sunspot is aimed at Earth at the time of the CME, it would interfere enough with the magnetic poles to seriously damage satellites and electrical power grids. The damage could include all unprotected electronics and automated control systems that operate life-sustaining critical infrastructures.
In addition to the electrical grid, the critical infrastructures include communications, transportation, food and water deliveries, oil and natural gas pipelines, banking and financial systems, emergency systems and satellites.
The last time AR 12192 aimed its flares toward Earth was in October and early November. Even though numerous flares ejected from the surface, none included CMEs. At the time, the flares skirted Earth and there was no direct hit, NASA scientists say.
AR 12192 then rotated out of view but now is coming back again. A few weeks ago, AR 12192 was large enough to fit 14 Earths into it.
The sunspot is not as large this time but still is big enough to fit 10 Earths into it, according to Holly Gilbert of the National Aeronautical and Space Administration.
AR 12209 ranks 33rd largest of 32,908 active regions recorded since 1874 and is the largest recorded since 1990.
“This time around,” Gilbert told Science.com, “it’s more likely to have some coronal mass ejections associated with it, even though the solar flares might be smaller.”
Gilbert is chief of the Solar Physics Laboratory at NASA’s Goddard Space Flight Center in Maryland.
“We have a good idea, based on the structure of the magnetic field and the sunspot, that it’s very possible that it will create some midlevel flares.”
The frequency of solar flares is due to the sun reaching its solar-storm maximum, which occurs every 11 years. Once it reaches its zenith, there still are flares, but they diminish until the cycle begins to repeat itself.
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Currently, the sun is in Solar Cycle 24, which when multiplied by 11 gives the length of time sunspots have been recorded on the sun. In 1755, extensive solar sunspot activity began to be recorded.
However, it wasn’t until 1859 that the largest solar flare was recorded in a direct hit on Earth. At that time, only the telegraph was in existence. The flare knocked out the telegraph system and caused local fires.
There even were reports that the oceanic underwater cable just laid from the United States to Europe similarly was knocked out and had to be restrung across the Atlantic Ocean.
On the surface of the sun, sunspots are blemish-like regions where magnetic fields become very tightly bundled, Gilbert said. The magnetic fields block light and heat from passing through the sunspot region, causing them to appear dark compared to the surrounding area.
Scientists still can’t predict if a sunspot will produce flares or kick out a CME, but NASA’s Solar Dynamics Observatory has a fleet of satellites that study the sun and its effects on Earth and know almost instantly when a flare has been ejected from the sun’s surface.
As the sun continues to revolve, AR 12209 is expected to become smaller with each passing rotation. However, it likely will make one more rotation before it disappears as the sun gradually heads toward a solar storm minimum when fewer active regions appear.