There is a high probability that Earth will be targeted by a solar flare on Monday due a rapidly growing giant sunspot on the surface of the sun.
The sunspot, known as AR3098, is currently facing in the direction of our planet meaning any eruptions that come from it are likely to interact with us. Solar activity news site Spaceweather.com reported it has quadrupled in size since September 11.
Sunspots are areas of the sun that hold powerful magnetic fields. These magnetic fields are so strong that they prevent some heat from the sun’s interior from reaching its surface, so sunspots appear darker and cooler than the surrounding areas.
When the magnetic field lines associated with sunspots suddenly shift or realign, a massive amount of energy is released. This energy can be released as a flash of radiation known as a solar flare, or a cloud of plasma and frozen magnetic fields known as a coronal mass ejection (CME), or both.
When these solar eruptions interact with Earth’s atmosphere and magnetic field, this can cause disruption to current technologies, including communication and navigation systems and power grids. These effects are referred to as geomagnetic storms.
The chances of an eruption from a given sunspot vary depending on how they are magnetically arranged; each sunspot can have multiple regions with different magnetic polarities, either positive or negative.
Sunspots are becoming more common as the sun is experiencing an increase in activity as part of its roughly 11-year solar cycle. On September 5, a hidden sunspot released an eruption so strong that one scientist said it would be studied “for years to come.”
In the case of sunspot AR3098, the chances of an eruption are highly likely, particularly due to its unstable magnetic field. Thankfully, they won’t necessarily be disruptive.
Solar activity news website Spaceweatherlive.com reported there was a 15 percent chance of M-class solar flares on September 12, plus a 70 percent chance of a weaker C-class flare. M-class flares are the second-strongest type of solar flare, ranked between M1 and M9 in increasing strength.
The National Oceanic and Atmospheric Administration’s (NOAA) Space Weather Prediction Center (SWPC) described the effects of solar flares via a radio blackout scale which starts with small M-class flares.
According to the scale, a weak M-class flare would have minor effects on Earth, including some small degradation of high-frequency radio communications and brief degradation of low-frequency navigation signals.
A strong M-class flare could have moderate effects including limited high-frequency radio blackout for tens of minutes and longer degradation of navigation signals.
It is unlikely that either of these events would be noticeable for the vast majority of people on Earth. It would take the strongest type of solar flare—an X-class event—for noticeable disruption.