An enormous sunspot that has doubled in size in only 24 hours is now facing Earth—meaning it could send a solar flare our way.
Sunspots are dark areas on the sun’s surface that are associated with intense bursts of radiation. They appear dark because they are cooler than other parts of the sun’s surface.
Sunspots are relatively cool because they form over areas where the sun’s magnetic fields are particularly strong—so strong that they prevent some heat within the sun from reaching its surface.
These tangled magnetic fields can sometimes suddenly reorganize themselves. When that happens, a sudden explosion of light and radiation is propelled away from the sun in the form of a solar flare.
The sunspot that has been growing in size recently is known as AR3038. Footage from NASA’s Solar Dynamics Observatory on Sunday shows how the sunspot has evolved over the past day or so, twisting and contorting.
“Yesterday, sunspot AR3038 was big. Today, it’s enormous,” reads the SpaceWeather.com website. “The fast-growing sunspot has doubled in size in only 24 hours.”
The magnetic field associated with the sunspot means it could potentially send an M-class solar flare at Earth—the second-strongest type. However, it is not known whether this will be the case.
As of Monday morning the National Oceanic and Atmospheric Administration’s Space Weather Prediction Center (SWPC) hadn’t issued any solar flare warnings.
If strong enough, solar flares can cause disruption on Earth, interfering with radio communication networks and navigation systems. This can cause problems for people who work in the marine or aviation industries, among others.
That said, it’s worth noting that an M-class flare would probably not be particularly disruptive in any case. Although M-class flares are the second-strongest type of solar flares, they only tend to cause moderate radio blackout events. An M9 flare, the strongest of the M-class, might cause loss of radio contact for ten minutes in affected areas of Earth and degradation of low-frequency navigation signals. M-class flares are also common.
It’s the least common X-class flares that can cause more serious trouble. X-class flares are the strongest type of flare. An X20 flare, for instance, would cause complete high frequency radio blackout on the daylight side of Earth for several hours, and boats and planes would not be able to use navigation signals during this time.
Thankfully such flares are very rare, estimated to occur less than once every 11 years—the length of an average solar cycle.