New Delhi: A new study by NASA scientists has revealed that the Sun has become increasingly active since 2008. The most well-known and well understood solar cycle is the 11-year long Schwabe cycle, with the waxing and waning of sunspot numbers and outbursts such as solar flares, filament eruptions and coronal mass ejections. The Sun reached the peak of the current cycle in October last year, but there are a number of periodic variations of the Sun, lasting between a few years to many thousands, that are named after the scientists that discovered them. Since the 1980s, solar activity has been on a decreasing trend, reaching the weakest on record in 2008. At that point, scientists expected the Sun to reach historically low levels of activity, but the Sun has bucked the trend.

New analysis reveals that the Sub is becoming increasingly active, that could lead to an uptick of space weather events such as solar flares, coronal mass ejections and solar storms. Scientists have been tracking solar activity since 1600s, when Galileo Galileo started counting and documenting sunspots, that are cooler, darker regions on the surface or photosphere of the Sun, produced by a concentration of tangled magnetic field lines. Clusters or sunspots are active regions are numbered and tracked by solar scientists, and are associated with solar outbursts such as solar flares and coronal mass ejections, where plasma from the surface of the sun is violently hurled outwards into space.

Clouds of charged, energetic particles are launched outwards through interplanetary space by these solar outbursts, that can induce geomagnetic storming on encountering the Earth. These solar storms impact satellites, communications systems and energy distribution networks that modern human civilisation relies so heavily on, which is why scientists are so invested in tracking solar activity. The quietest periods of solar activity was a three-decade stretch between 1645 and 1715, as well as a four-decade stretch between 1790 and 1830. These longer-term trends are more difficult to predict. Researchers had expected the ‘deep solar minimum’ of 2008 to mark the start of a new low-period in solar activity, but the Sun has proven difficult to predict. The research has been published in The Astrophysical Journal Letters.