From UPSC perspective, the following things are important :
Prelims level : Solar minima and maxima
Mains level : Solar minima and maxima, its impact on space weather and earth
The sun is said to have gone into a state called the ‘solar minimum’ and is about to enter the deepest period of ‘sunshine recession’ as sunspots are virtually not visibly at all.
Practice question for Mains:
Q. What are Solar minima and maxima? Discuss its impact on space weather and the Earth.
What is a solar minimum and why is it happening now?
- Sun has a cycle that lasts on average 11 years, and right now we are at the peak of that cycle.
- Every 11 years or so, sunspots fade away, bringing a period of relative calm.
- This is called the solar minimum. And it’s a regular part of the sunspot cycle.
- While intense activity such as sunspots and solar flares subside during solar minimum, that doesn’t mean the sun becomes dull. Solar activity simply changes form.
What about Solar Maximum?
- Solar minima and maxima are the two extremes of the Sun’s 11-year and 400-year activity cycle.
- At a maximum, the Sun is peppered with sunspots, solar flares erupt, and the Sun hurls billion-ton clouds of electrified gas into space.
- Sky watchers may see more auroras, and space agencies must monitor radiation storms for astronaut protection.
- Power outages, satellite malfunctions, communication disruptions, and GPS receiver malfunctions are just a few of the things that can happen during a solar maximum.
What are its effects on Earth?
a) On space weather
- The Solar wind from coronal holes will temporarily create disturbances in the Earth’s magnetosphere, called geomagnetic storms, auroras, and disruptions to communications and navigation systems.
- The space weather during solar minimum will also affect Earth’s upper atmosphere on satellites in low Earth orbit changes.
- This means that the Earth’s upper atmosphere will cool down which is generally heated and puffed up by ultraviolet radiation from the sun.
- However, the heat at the upper atmosphere of our planet helps Earth to drag debris and keep the low Earth orbit clear of manmade space junk.
- Apart from this, the solar minimum will change the space weather significantly which will lead to an increase in the number of galactic cosmic rays that reach Earth’s upper atmosphere.
- These Galactic cosmic rays are high energy particles which are a result of distant supernova explosions and other violent events in the galaxy.
b) On astronauts
- According to NASA the sun’s magnetic field weakens and provides less shielding from these cosmic rays during a solar minimum which will directly increase the threat to astronauts travelling through space.
- This may cause health risks to astronauts travelling through space as the sun’s magnetic field weakens and provides less shielding from these cosmic rays.