At least 17 solar eruptions from a single sunspot have blasted into space in recent days, and moderate geomagnetic storms could reach Earth by Thursday (March 31)
The flares were caused by an overactive sunspot called AR2975, which has been erupting since Monday (March 28).
What are Sunspots?
Sunspots are darker, cooler regions on the sun’s surface known as the photosphere.
The temperature of the photosphere is 5,800 degrees Kelvin. Temperatures in sunspots are around 3,800 degrees K. Only in comparison to the brighter and hotter regions of the photosphere around them do they appear dark.
Sunspots can be extremely large, with diameters of up to 50,000 kilometres. They are caused by unknown interactions with the Sun’s magnetic field. However, a sunspot is similar to the cap on a soda bottle: if you shake it, it can cause a large eruption. Sunspots form over areas of high magnetic activity, releasing energy in the form of solar flares and large storms known as coronal mass ejections.
Sunspots are solar eruptions that occur when magnetic lines twist and realign abruptly near the visible surface.
Coronal mass ejections (CMEs), or streams of charged particles that shoot into space, are sometimes associated with these explosions.
The Solar and Heliospheric Observatory, as well as NASA’s powerful Solar Dynamics Observatory, captured stunning views of the solar eruptions.
“The eruptions have hurled at least two, possibly three, CMEs toward Earth,” wrote SpaceWeather.com of the event.
According to NASA and the National Oceanic and Atmospheric Administration, the first CME is expected on Thursday (March 31), with at least one more on Friday (April 1), according to the report.
CMEs (coronal mass ejections) are large plasma and magnetic field expulsions from the Sun’s corona. They have the ability to eject billions of tonnes of coronal material and carry an embedded magnetic field (frozen in flux) that is stronger than the interplanetary magnetic field (IMF) strength in the solar wind.
CMEs travel at speeds ranging from less than 250 kilometres per second (km/s) to nearly 3000 km/s as they leave the Sun. CMEs aimed at Earth can reach our planet in as little as 15-18 hours. The arrival of slower CMEs can take several days.
As they travel away from the Sun, they grow in size, and larger CMEs can cover nearly a quarter of the distance between Earth and the Sun by the time they reach our planet.
The more explosive CMEs usually start when the Sun’s lower corona’s highly twisted magnetic field structures (flux ropes) become overly stressed and realign into a less tense configuration, a process known as magnetic reconnection.
Solar activity is monitored by NASA and other space agencies
Although auroras (northern lights and southern lights) are notoriously difficult to predict, modelling suggests that the particles could cause G2 or G3 (moderate) geomagnetic storms.
While this potential storm is only mild, NASA and other space agencies monitor solar activity in order to improve solar weather forecasts.
A strong flare aimed at Earth, combined with a large CME, could cause problems such as power line damage or satellite disabling.
Overall, the Sun is expected to be relatively quiet in 2022, as we are still near the start of the 11-year solar cycle, which began in December 2019.
There are usually fewer sunspots and eruptions at the start of a cycle. As we get closer to the peak, which is expected in mid-2025, activity should pick up.
According to the report, scientists are debating how strong this current solar cycle will be, with forecasts indicating that the average number of sunspots may be lower than usual.
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