Kodaikanal Solar Observatory Digitized Data probes Sun’s rotation over the Century

In News-Recently, Scientists have estimated Sun’s rotation over the Century from data extracted from old films and photographs that have been digitized.

About Discoverer/ Researcher:

• Following institutes studied solar rotation by tracing sunspots from century-old digitized films and photographs. 
  • Aryabhatta Research Institute of Observational Sciences (ARIES), an autonomous institute under the Department of Science and Technology (DST),
  • Max Planck Institute for Solar System Research, Goettingen, Germany and
  • Southwest Research Institute, Boulder, USA
• The old films and photographs were taken at the Kodaikanal Solar Observatory (KoSO) of the Indian Institute of Astrophysics (IIA), an autonomous institute of DST, and have now been digitised.

Benefits of Discovery

• Solar Magnetic Field: The estimation would help study the magnetic field generated in the interior of the Sun.
  • The magnetic field causes sunspots and results in extreme situations like the historical mini-ice age on Earth (absence of sunspots).
• Prediction of Solar Cycles: It could also help predict solar cycles and their variations in the future.
  • The researchers can differentiate the behaviours of the bigger and smaller solar spots for the first time.

Key Findings

•  Differential Speed of Poles and Equator: The Sun rotates more quickly at its equator than at its poles.
  • Over time, the Sun’s differential rotation rates cause its magnetic field to become twisted and tangled.
  • The tangles in the magnetic field lines can produce strong localized magnetic fields.
  • When the Sun’s magnetic field gets twisted, there are lots of sunspots.
  • The sunspots which form at the surface with an 11-year periodicity are the only route to probe the solar dynamo or solar magnetism inside the Sun and hence measure the variation in solar rotation.

Source: PIB