The Solar Cycle 25

On 15th September 2020, our scientific research community in Heliophysics has confirmed that a new Solar Cycle has started. To be precise, we have entered into Solar Cycle 25. It is a substantial task for each one of us to be familiar with more about our Sun’s behaviour. So, let’s discourse some essential solar physics.

What does the Solar Cycle mean?

Our star, the Sun is a gigantic ball of electrically charged hot gas. As the movement of charged gas occurs, a powerful magnetic field is generated. Accordingly, our Sun’s magnetic field undergoes some cyclic changes which repeats in every 11 years called Solar Cycle. During this time period, Sun flips its north and south poles. This cycle bases variations in solar activity which do occur on the surface of the Sun. This activity majorly comprises solar flares, solar winds, and sun spots. Sun spots are nothing but some blackish spots on the surface of Sun from Earth’s frame of reference. It may look boring in simple images as there may seem no processes occurring. But, the reality is just the opposite as there are certain frequent sudden explosions of electromagnetic radiations are seen. We call those explosions simply as solar flares which are basically stemmed by reorganization of magnetic lines near the sun spots. Because of Sun’s surface magnetic engagements, we are only able to see sun spots in black colour from our Earth. The fundamental methodology in characterizing Solar Cycle is done by counting the number of sun spots. At the commencement phase of each Solar Cycle, sun spots will be least in number, and the stage can be called as solar minimum. As the cycle evolves, the number of sun spots gets increased and reaches a maximum called solar maximum. By the end of cycle again it touches solar minimum and subsequently Sun will go in into next cycle. The coronal mass ejection of Sun will also get increased by the intensification of solar activity. These expulsions can have upshots on other celestial entities too including our Earth. Moreover, the stunning phenomena of aurora borealis and aurora australis are the result of interaction of our Earth’s Magnetosphere with these solar eruptions. Concurrently there are a lot of negative impacts as well, these solar radiations also cause damages to our satellites, radio communications, and even to electricity grids on our Earth. Certain cycles may have more solar activity and there by higher number of solar maximums. At the same time, some cycles may not have, then there will experience more frequent solar minimums. The solar conditions including all these phenomena are basically called space weather. Better the space weather forecasting, better will be the ease of protection of our satellite electronics, radio communication systems, etc. Furthermore, these solar-flare-coronal radiations can be vicious to the health of our astronauts particularly who do work outside the International Space Station (ISS). Therefore, a precise space weather prediction is significant in all the respect.

Reference/Picture courtesy: NASA Solar Dynamics Observatory