These dark spots had been recorded by Galileo himself

A city-based physicist and his colleagues have unravelled the mystery behind an occurrence that has intrigued scientists across the world – the disappearance for nearly two years of sun spots on the surface of the sun. These dark spots had been recorded by Galileo himself.

The findings of Dibyendu Nandi, a researcher at the India Institute of Science Education and Research, Kolkata, and his colleagues Andres Munoz-Jaramillo and Petrus Martens were published in the prestigious international journal “Nature” on Thursday.

Sunspots are created from the interaction of magnetic fields with the ionised gases in the interior of the sun that emerge to its surface because of the buoyancy of the magnetic fields.

These globs of charged particles, called plasma, are in a continuous flow from the surface of the sun to its interiors resulting in a flow of plasma, which is often called the “great conveyor belt”, explained Dr. Nandi to The Hindu.

A computer model developed by the researchers that is based on equations of the activity in the core of the sun as observed from satellites explains this flow of plasma. From the model they have been able to explain the lag in the observance of the sunspots for nearly two years.

“It happened as a result of speeding up in the 1990s and then slowing down after 2000 of the flow of plasma from the surface to the core and its subsequent re-emergence. It can be visualised as two cars moving at different speeds on the highway as a result of which the difference between them is increasing,” Dr. Nandi said.

“Sun spots have been well documented for over 400 years. The last time such a lag was reported was nearly a hundred years ago in 1913,” he said.

If this solar activity can be predicted, it will have a significant impact on both aviation and monitoring of satellites because sunspots affect what is described as space weather.

The explosions containing the energy of a thousand-billion atom bombs emit from the sun and can reach the earth, in a way like lightning. However, the earth and weather here are protected from them because of its own magnetic field, he explained.

However, satellites orbiting the earth are not protected from these emissions.