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SOLAR CYCLE

5th January, 2022

What is the solar cycle?

  • The solar cycle is the cycle that the Sun’s magnetic field goes through approximately every 11 years.
  • Solar minima and maxima are the two extremes of the Sun's 11-year activity cycle.

Solar Minimum

  • Solar minimum is the period of least solar activity in the 11-year solar cycle of the Sun.
  • During this time, sunspot and solar flare activity diminishes, and often does not occur for days at a time.
  • Solar minima are correlated with changes in climate.
  • The most infamous Solar Minimum happened between 1645 to 1715, termed as “Maunder Minimum” - when sunspots were very rare for an extended period.

 

Solar Maximum

  • During solar maximum, large numbers of sunspots appear, and the solar irradiance output grows tremendously.
  • At solar maximum, the Sun's magnetic field lines are the most distorted due to the magnetic field on the solar equator rotating at a slightly faster pace than at the solar poles.
  • Large solar flares occur during a maximum.

What is a sunspot?

  • It’s an area of intense magnetic activity on the surface of the Sun—a storm—that appears as an area of darkness.
  • Sunspots are indicative of solar activity, giving birth to solar flares and coronal mass ejections (CMEs).
  • Sunspots have been continuously counted each day since 1838.
  • This has allowed solar scientists to describe a repeating pattern in the wax and wane of activity on the Sun’s surface—the solar cycle.

How does the solar cycle affect Earth?

  • The more charged-up the solar wind headed towards Earth, the brighter and more frequent are the displays of Northern Lights and Southern Light (Aurora)
  • For example, the solar storm of 1859 struck the Earth with such intensity that the northern lights were visible as far from the poles as Cuba and Hawaii.
  • Power outages, satellite malfunctions, communication disruptions, and GPS receiver malfunctions are other few things that can happen during a solar maximum.