The Reason Solar Flares Are Hard to Predict

The Reason Solar Flares Are Hard to Predict

A few weeks ago Australia was blessed with some breathtaking auroras, which were the result of solar flares from the sun.

While these produce some pretty skies, they cause chaos to our technology due to the magnetic intensity, so expect technology like MRIs, planes and satellites to be impacted by the galactic weather event.

But there is another tidbit about solar flares, they’re hard to predict. 

CSIRO space weather scientist, Dr John Morgan spoke with Gizmodo Australia about solar flares and why they are so dang hard to track. 

What is a solar flare?

Solar flares are a sudden and localised enhancement in the ultraviolet and x-ray radiation emitted by the Sun. Morgan said they are caused by magnetic activity on the Sun. 

“Sunspots are actually planet-sized bundles of strong magnetic fields (as strong as in MRI machines),” he said.

“These sunspots are being churned by plasma flows beneath the surface of the Sun. When sunspots collide, it stresses the magnetic bundles until they snap. This leads to solar flares and eruptions.”

Why are solar flares hard to predict?

Tracking and predicting solar flares isn’t an easy job, Morgan said predicting them is much more uncertain than predicting conventional weather, and there are lots of reasons for this.

“One big difference is an extra variable: the magnetic field of the storm. This is both important to how the storm impacts the Earth and very difficult to measure remotely,” he said. 

Morgan explained another problem is that once an event happens on the sun, us mere mortals have little to no ability to track it as it comes towards Earth. 

“Often the first definitive information that we have is when storm reaches a cluster of satellites that we have parked up-stream of the Earth towards the Sun,” he said.  

“Among other things, these satellites measure the speed of the solar wind, and the size of the southward pointing magnetic field. These give a very good indication of what is heading towards us, however, they only give us about an hour’s notice.”

The CSIRO along with its national and international partners is actively working on novel ways to track storms on their way to Earth, as well as trying to measure their magnetic field remotely, Morgan added.

The number of solar flares generally corresponds to the number of sunspots on the Sun. It is incredibly difficult to predict if/when large solar flares are likely to occur, Morgan explained. 

“Generally speaking, we know sunspot numbers wax and wane over an 11-year solar cycle,” he said. 

“The US National Oceanic and Atmospheric Administration (NOAA) has forecast the solar maximum will peak in 2024, making flares and coronal mass ejections more likely.”

How does a solar flare impact Earth?

Once a solar flare is emitted, the radiation takes about eight minutes to reach the Earth, Morgan said. 

“The energetic radiation can ionise atoms in the Earth’s upper atmosphere and cause it to puff up. This can cause radio communications blackouts, errors in global positioning systems, and increase drag on satellites, changing their orbits,” Morgan explained.  

“The radiation is commonly followed by a cloud of plasma that travels to Earth more slowly and can trigger a large disturbance of the Earth’s magnetic field called a geomagnetic storm.

“This can produce further impacts such as errors in satellite navigation and effects on power networks.”

With the recent solar flare occurring only weeks ago, it didnt impact Australia’s technological infrastructure too much, Morgan said. 

“It appears we got lucky. The recent solar storm appears to have had very few and minor impacts,” he explained. 

“There were a number of actions taken to mitigate the impact of the storm – for example, some airlines re-routed polar flights and there were some communication disruptions and impacts to some precision satellite navigation.”

But, we aren’t out of the woods just yet as Morgan said we cannot assume that there won’t be more severe impacts in the future. 

“As recently as 2022, 38 Starlink satellites came back down to Earth shortly after launch, largely due to increased atmospheric drag during a relatively minor space weather disturbance,” he said. 

“Potential space weather impacts include more serious communications and satellite navigation outages, disruption to aviation, and even extended local power outages.”

Image: CSIRO

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