Indian astronomers believe they have discovered why the spots on the Sun have virtually disappeared from its surface for two years. Indeed, between 2008 and 2009, scientists observed a virtual absence of sunspots.
This sharp drop, a record lull since 1913, has all the more surprising scientists that the Sun was supposed at the time to be at a peak of activity after a cycle estimated at about 11 years .
A complex phenomenon
These spots are characterized by a high magnetic intensity. They are, in a way, like concentrated nodes of plasma (electrically charged particles) that emerge on the surface of the star.
This plasma is constantly moving on the surface, a bit like the oceans on the Earth. Science knew that these flows flow in Ecuador, then move towards the poles, before diving below the surface to emerge in Ecuador and start a new cycle.
The researchers compare the action of plasma to a treadmill.
With an average speed of 65 km / h, the passage of plasma in the entrails of the Sun recharges particles that form visible spots on its surface.
A late cycle
Dr. Dibyendu Nandi and his colleagues at the Indian Institute of Educational Sciences and Research in Kolkata modeled cycles and solar flows over a period of about 2,000 years to better understand the phenomenon.
Analyzes show that the origin of the “problem” of sunspots dates back to the late 1990s, as the Sun began a new cycle. At that time, the “treadmill” would have accelerated, which would have resulted in a slowdown in plasma flows and caused a delay in the recovery of solar activity.
This gap has since been filled, since our star produced last February 14 its strongest eruption for more than four years.
This eruption was accompanied by a powerful magnetic explosion in the sun’s corona that projected about 900 km per second of ionized plasma into space.
Consequences for the Earth
This type of solar flares can cause serious disruption to ground and space telecommunications and power distribution systems.
The details of this work are published in Nature magazine .