Global Geological And Climatic Events

What is Solar Minimum?


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.
Notify of
Inline Feedbacks
View all comments