Research explained missing sunspots

WASHINGTON: A recent research explained the “puzzle” of recent period of decreased solar activity during the Sun’s 11-year cycle. The research was conducted jointly sponsored by India’s top science body and NASA and done by a scientist from Kolkata.

The solar cycle, or the solar magnetic activity cycle, is a periodic change in the amount of irradiation from the sun that is experienced on Earth.

It has a period of about 10.7 years (approximately 11 years), and is one component of solar variation, the other being aperiodic fluctuations.

During 2008-2009 solar scientists around the world were puzzled by the extended disappearance of sunspots.

The recent solar minimum, a period characterized by a lower frequency of sunspots and solar storms, was the deepest observed in almost 100 years. The solar minimum has repercussions on the safety of space travel and the amount of orbital debris our planet accumulates, a NASA release said.

Lead author Dibyendu Nandi of the Indian Institute of Science Education and Research in Kolkata said, “Plasma currents deep inside the sun interfered with the formation of sunspots and prolonged the solar minimum.”

Funded by the Department of Science and Technology (DST) of India and NASA’s Living With a Star Programme, the research revealed that during this deep solar minimum, the sun’s magnetic field weakened, allowing cosmic rays to penetrate the solar system in record numbers, making space a more dangerous place to travel.

At the same time, the decrease in ultraviolet radiation caused Earth’s upper atmosphere to cool and collapse.

Solar variation causes changes in space weather and to some degree weather on Earth. However, changes in solar brightness are too weak to explain recent climate change. The cycle is observed by counting the frequency and placement of sunspots visible on the Sun.

Also Richard Fisher, director of the Heliophysics Division in NASA’s Science Mission Directorate at the agency’s headquarters in Washington said, “This research demonstrates how observations from Heliophysics System Observatory missions stimulate new theories and advance modeling techniques.”