During the different phases of the solar cycle, the intensity of solar activities also varies and the phases during which they are at their peak and nadir are known as solar maxima and minima respectively.
As for the comparison between solar cycle 24 and solar cycle 25, the scientists have termed the new solar cycle weak just like the previous cycle.
American space agency NASA and the National Oceanic and Atmospheric Administration (NOAA) have issued a joint statement announcing the beginning of solar cycle 25. Being the centre of the solar system, the Sun exerts huge impacts on the overall solar, climatic and weather conditions of the planet and its cycle also holds great significance, the Indian Express reported.
What is a Solar Cycle? Just like various seasons are manifested on the surface of the Earth, the Sun also goes through a cycle of eleven years. During the different phases of the solar cycle, the intensity of solar activities also varies and the phases during which they are at their peak and nadir are known as solar maxima and minima respectively. Space scientists keep a track of these phases with the help of the number of sunspots on the surface of the Sun. When the number of sunspots is maximum the phase is termed solar maxima and when the number of sunspots are minimum the phase is termed the solar minima. Spots on the solar surface are characterised as small, dark and cooler areas that emerge on the surface of the Sun. Beginning from appearing at the higher latitudes of Sun, these spots progress towards the equator of the Sun. Scientists determine the commencement of the new cycle when the number of sunspots are at their lowest.
Since the space phenomena are always in a flux, a battery of solar physicists from NASA and NOAA observe the data of around six to eight months before confirming that the Sun has entered its solar minima phase and a new solar cycle is set to begin.
How do scientists record sunspots on the solar surface? In previous centuries, scientists relied on Telescopes to observe the sunspots on the solar surface. However, with the arrival of new technology like satellite viewing, the task of observing the solar cycle of the Sun is completed more precisely. For the new solar cycle, the scientists have said that the previous cycle ended in December 2019 and a new solar cycle is set to begin.
How does the Sun transition between different cycles? Starting from December 2008, the solar cycle 24 before ending in December 2019 had stopped its solar activities to a very large extent in the last few months. Reportedly, no sunspots were observed for a total of 281 days in the year 2019. However, soon after the month of December, the solar activities have started picking up hinting at the arrival of the new cycle.
As for the comparison between solar cycle 24 and solar cycle 25, the scientists have termed the new solar cycle weak just like the previous cycle. However, a weak cycle does not translate into the absence of extreme space weather and other phenomena. Doug Biesecker, panel co-chair and solar physicist at NOAA’s Space Weather Prediction Centre, Colorado was quoted as saying that despite the new cycle being a weak and less active cycle, the risks of extreme space weather remain. Dibyendu Nandi from IISER, Kolkata also attested to the findings of the NASA scientists and told IE that the solar cycle 25 began with a hesitant start. He also said that during the transition from cycle 24 to cycle 25, there were days when the number of spots on the solar surface dropped to just 1.8. He further said that the condition of deep minima at the beginning of cycle 25 has also troubled the scientists’ community.
How can space weather impact humans? Solar flares, high-speed solar wind and Coronal Mass Ejections (CME) are some of the events that are a regular feature in the Space Weather. Solar storms and other extreme events could pose danger to some of the space dependent operations like Global Positioning System (GPS), Radio and Satellite communication and space exploration programmes of various countries. Jake Bleacher, chief scientist at Human Exploration and Operations Mission Directorate, NASA was quoted as saying that awareness about the space weather helps space agencies take mitigation measures for various space exploration missions.