Giant Sunspot Cluster Could Pelt Earth with a Cannibal Coronal Mass Ejection

A sunspot cluster as wide as 16 Earths has already erupted its magnetic field and solar plasma at least five times, several of which could merge in Earth’s atmosphere this weekend to form a “cannibalistic” solar storm.

The event prompted the National Oceanic and Atmospheric Administration (NOAA) to issue its first G4 geomagnetic storm watch since 2005. The National Oceanic and Atmospheric Administration (NOAA) categorizes solar storms on a five-point scale, with G4 standing for “severe” solar storms. Severe solar storms can cause voltage surges in the power grid and affect satellite and high-frequency radio communications, said Rob Steenburgh, a space weather scientist at NOAA, adding that operators in these industries have adapted to protect their equipment during these storms. These protections can include backup systems and radiation shielding, as well as temporary changes in operations. However, the potential new storm could become public knowledge through colorful auroras seen from the northern part of the continental U.S. and possibly in the southern states, depending on the intensity of the storm.The G4 watch goes into effect at noon this afternoon.

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“We expect this activity to continue through Sunday,” Steenburgh said.

The sunspot cluster is similar in size to the one that triggered a plasma and magnetic field eruption in 1859, called a coronal mass ejection (CME), and triggered the Carrington event, the most intense geomagnetic storm ever recorded. This event disrupted the only mass communication available at the time, the telegraph network, and triggered auroras around the world.

However, current sunspots do not necessarily cause storms of a similar magnitude.Steenburgh said that since 1996, there have been 141 sunspot clusters as large or larger than the current one, known as Active Region 3664 (AR3664).

“CMEs headed for Earth are probably much smaller and less powerful than the large CMEs that led to the Carrington event,” said astronomer Tony Phillips, who runs Spaceweather.com, a website that tracks space weather events.

At least some of the CMEs spewed out by the sunspot group over the past few days could merge, creating so-called “cannibal CMEs”, Palmerio said, adding that the impact would depend on the speed of the CMEs and the direction of their merging magnetic fields. These electrically charged bubbles can travel away from the Sun at speeds ranging from less than 55,000 miles per hour to more than 6.7 million miles per hour.

A few days ago, the sunspot group rotated into Earth’s field of view. At the time, the area looked fairly normal. But then “it just blew up into this behemoth,” Phillips said. The fortunate timing allowed researchers to observe the development of the giant sunspot cluster, Palmerio said. Over the next few days, the sun’s rotation will mean that the sunspot cluster will be moving away from Earth, Steenburgh said, so any further CMEs it sends out will go harmlessly into space. The spot could reappear, however. Sunspot clusters of this size usually last for months, and a new rotation of the sun could bring the behemoth into Earth’s view within two weeks.