The Sun recently exploded, causing a brief but intense radio blackout in the western United States and the Pacific Ocean as it affected the Earth's upper atmosphere.

On 2 July 2023, at 7.14 a.m. Eastern Standard Time, an active sunspot region called AR 3354 unleashed a class X solar flare, the most powerful category our Sun is capable of.

The X1.0 magnitude flare (the largest ever recorded was X28, about 20 years ago) ionised the Earth's upper atmosphere, interfering with high-frequency radio signals on the side of the Earth facing the Sun at the time.
As serious as it sounds, the impact on Earth was less severe than it could have been, as the flare faded without further incident. Astronomers saw no sign of the coronal mass ejection that usually accompanies such events, which would eject plasma streams into space.

The flare was consistent with the upward trajectory of the current solar cycle, suggesting some rowdy months ahead as we head towards the upcoming 11-year peak of solar activity. According to the Royal Observatory of Belgium, sunspot numbers have reached a 21-year high, with the average for June reaching 163 sunspots per day.
This kind of activity is quite normal for the Sun. Every 11 years it goes through peaks and troughs of activity, called solar maxima and solar minima. It is not known exactly what drives these cycles, but we record it based on sunspot numbers. This is because the Sun's magnetic field controls its activity, and sunspots are transient regions where magnetic fields are particularly strong.

Solar flares and coronal mass ejections are usually caused by the rupture and reconnection of magnetic field lines in sunspot regions. This causes a burst of energy that manifests as a solar flare. The more sunspots there are on the Sun, the more often these flares occur.
The last solar minimum and the end of Solar Cycle 24 were recorded in 2020. We are now in Solar Cycle 25 and are heading towards solar maximum around July 2025. But this solar cycle is a little out of our expectation, with NASA and NOAA predicting that the cycle will peak relatively quietly with about 115 sunspots at solar maximum.

It is not entirely clear why the Sun is much more active than the official estimates. Monitoring this process could tell us more about what is going on inside the Sun - of which we don't have a very clear picture - and allow us to make better predictions going forward.
This is important because, as the recent flare showed, solar activity can affect us here on Earth, and not just in the form of radio blackouts. A strong enough flare can interfere with satellite communications, including navigation. It can cause surges and outages in the electricity grid. It can disrupt migratory behaviour in animals.

In 1859, a coronal mass ejection created a solar storm called the Carrington Event, which caused catastrophic failure of telegraph systems. We have yet to record anything this powerful since then, but experts say it is a distinct possibility that could change the world.
The most powerful solar cycle on record took place between 1954 and 1964. At its peak, we recorded a maximum of 285 sunspots.

Solar Cycle 25 isn't quite at that level yet, but scientists predict it could be one of the most powerful cycles ever recorded, and we certainly seem to be heading down that path. Let's hope we can learn something new about the mysterious inner workings of our beautiful home star from this wild solar weather.

 

Source: https://www.sciencealert.com/