In an unusual space weather event, Earth is bracing for a “cannibal” coronal mass ejection, or CME, from the Sun, a large cloud of magnetized plasma that could potentially trigger minor geomagnetic storms and power outages. The term for this solar storm, which may sound harrowing, describes a relatively rare cosmic phenomenon that scientists are still striving to fully understand.
Typically, our planet gets hit by coronal mass ejections (CMEs) – massive bursts of gas and magnetic field released from the Sun’s corona – fairly frequently. Yet, this incoming wave of energy is anything but typical.
Today’s CME is classified as a “cannibal” due to its formation following a series of solar storms and a peculiar “dark eruption.” This CME distinguished itself from regular ones as it absorbed a preceding ejection, essentially “eating” it to create a much larger and more powerful cloud of gas.
According to scientists, this cannibal CME, despite its ominous name, is unlikely to pose a significant threat to our electronic systems, satellites, or power grids. However, there is the possibility of minor outages and blackouts as the CME strikes Earth today.
“These storms manifest as major disturbances in Earth’s magnetic field, potentially causing various space weather effects,” says Sean Elvidge, an associate professor of space environment at the University of Birmingham. While on one hand, they can disrupt communication systems by causing radio blackouts, on the other, they can lead to spectacular natural light shows in the form of auroras, he explains.
Four days ago, a solar flare distinguished by unusually cool plasma, hence termed a “dark eruption,” was launched in tandem with a CME. Within 24 hours, another, much faster CME erupted from a separate, larger sunspot. This second, speedier CME eventually caught up with the first, creating the “cannibalistic” plasma wave that we now anticipate.
Forecasts by the Space Weather arm of the Met Office and the US-based Space Weather Prediction Center predict unsettled to active geomagnetic activity at first, with the chance of minor geomagnetic storms.
Such impacts are fairly infrequent because they necessitate successive CMEs traveling at specific speeds and in perfect alignment. However, a similar event took place just two years ago, prompting a major geomagnetic storm.
These storms are categorized according to the G-scale, with G-1 being the weakest, causing mild power grid fluctuations and minor impact on satellite operations. The scale progresses through to G-5, the most extreme level, which can instigate blackouts, damage transformers, and make it difficult to control satellites in low-Earth orbit. The storm anticipated for today is predicted to be of the G-1 type.
While cannibal CMEs are quite rare, they become increasingly more common as the sun nears the peak of its 11-year solar cycle. This cycle peak, the next of which is due in 2025, coincides with a greater instability in the Sun’s magnetic field, thereby increasing the number of sunspots from which CMEs can erupt.
Although initial predictions suggested the 2025 peak would be weaker than past solar maximums, recent research posits that it may be stronger and could even occur earlier than expected.
Interestingly, the “cannibal” solar storm arriving today might hold a pleasant surprise for skywatchers, particularly in the Northern parts of Britain. They could have the opportunity to witness the Northern Lights, or aurora borealis, a stunning natural light display triggered by geomagnetic storms.
As the CME sweeps into Earth, it’s predicted to escalate the geomagnetic activity from unsettled to minor or moderate by tomorrow. Consequently, between 9pm GMT and midnight, auroras are likely to be visible, especially from darker, rural areas of Northern England, Scotland, and Northern Ireland.
However, predicting the precise location for observing the Northern Lights can be a challenge, as the conditions can rapidly change.
“To predict exactly where you can see the northern lights is difficult as conditions can change quickly,” said Professor Don Pollacco from the Department of Physics, University of Warwick. Nonetheless, he suggests looking towards the northern horizon from a dimly lit rural environment, preferably away from city lights.
Though the geomagnetic activity is predicted to diminish after this period, the spectacle of auroras could still be observed in the far North of the UK on the following Saturday evening. It’s an extraordinary instance of nature’s power and beauty, reminding us of the immense energy of our Sun, and the effects that this distant star can have on our planet.