Earth is bracing for an extreme geomagnetic storm this week after the sun blasted a massive solar flare toward our planet this week.
Sunspot AR3842 – a dark, fast-growing region of strong magnetic fields on the sun’s surface – erupted Tuesday evening around 6pm ET, producing the second-strongest flare in the last five years.
The flare has already caused a shortwave radio blackout over Hawaii and shot a coronal mass ejection (CME) – a blast of solar plasma and high energy particles – into space.
The National Oceanic and Atmospheric Administration (NOAA) predicted that the CME will slam into Earth early to mid-day on October 5.
The collision could trigger a strong geomagnetic storm that could cause radio blackouts, power grid damage and disruptions to satellite communications.
NASA’s Solar Dynamics Observatory captured this image of the solar flare that erupted on Oct. 1, 2024, seen as the bright flash in the lower left
Solar flares are powerful bursts of radiation that come from a release of magnetic energy associated with sunspots. They are the largest explosive events in the solar system.
Tuesday’s flare was an X7.1, according to NASA.
X is the largest class of solar flare, which can trigger radio blackouts across the globe and widespread damage to satellites, spacecraft and power grids.
It is followed by M, C, and B-class in descending order of severity. Within each letter class, there is a finer scale of one to nine that further specifies the flare’s intensity.
This was the second largest solar flare to occur since the sun entered its 25th recorded solar cycle in December 2019.
The solar cycle refers to the roughly 11-year cycle of solar activity that’s driven by the sun’s magnetic field.
The sun’s activity fluctuates throughout this cycle, becoming more active during solar maximum – the stage we’re currently in – and less active during solar minimum.
The largest flare of this cycle to-date occurred in May, when a X8.9 flare erupted from the sun’s surface.
Solar flares can trigger coronal mass ejections (CMEs). A CME is currently hurtling toward our planet at nearly 800 miles per second
When CMEs impact our planet, they can trigger dazzling auroras. But they can also significantly disrupt and damage communications and power infrastructure
The one on Tuesday sent radiation blasting through Earth’s magnetosphere, ionizing the upper atmosphere and triggering a temporary radio blackout across a wide area above the Pacific Ocean, including over Hawaii.
It also sent a CME hurtling towards Earth at hundreds of miles per second. NASA predicts this blast of solar radiation will slam into our planet sometime between Saturday and Sunday, according to spaceweather.com.
When CMEs impact Earth’s magnetosphere – the region of space surrounding our planet that is dominated by its magnetic field – they can cause major disturbances called geomagnetic storms.
Geomagnetic storms can cause dazzling aurora displays to appear at unusually low latitudes, and it’s likely that we could see some this weekend.
But like solar flares, they can also trigger radio blackouts, disrupt satellite communications and damage power grids.
The impact of this storm will depend on how strong it is. Geomagnetic storms are classified on a scale of G1 (minor) to G5 (extreme).
More severe storms are rarer, cause more widespread aurora and have a greater effect on Earth’s infrastructure.
It’s currently unclear exactly when this weekend’s geomagnetic storm could hit, and how strong it will be.
But experts at NOAA have issued a G1 to G3 geomagnetic storm watch for Thursday, Oct. 3 through Saturday, Oct 5, with the most likely timing of the CME’s impact slated for Saturday.
This week’s solar activity adds to mounting evidence that the sun has entered solar maximum, the period during its 11-year cycle when solar activity is at its peak.
In 2019, scientists predicted that solar maximum would begin around July 2025. But as the sun’s activity ramped up over the course of 2024, it became clear that this peak would arrive much sooner than expected, prompting experts to revise their forecast.
The sun has already shot out 41 X-class solar flares this year. That’s more than have occurred in the last nine years combined, according to spaceweather.com.
In an average year, X-class solar flares only occur around 10 times.
Solar maximum could last for at least another year, so we can expect to see plenty more intense solar flares, CMEs and geomagnetic storms battering our planet in 2025.
