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Even “quiet” sun can lash Earth: Scientists

The sun can strike the earth with powerful winds even when it is in its dormant phase

Singapore, September 19 -- U.S. scientists revealed that the sun can lash the Earth with powerful winds even when it is in the quiet stage of its 11-year solar cycle. These winds can lead to an interruption in the communication system and aviation and power lines.

The activity on the sun is measured by observing the number of sunspots on its surface. There is a point when the number of sunspots reaches at the highest and this is known as the “solar maximum”. It then declines to come back to a minimum number.

When the sunspots are at the peak, strong solar flares and geomagnetic storms expel huge amounts of energy into space. All these storms crash into the magnetic fields that shield the Earth. They can blow out satellites, disturb communications and cause colorful aurorae.

However, scientists at the National Center for Atmospheric Research in the United States and the University of Michigan reported that the Earth was lashed by powerful solar winds last year despite the sun being in its quite phase.

Sarah Gibson of the center’s High Altitude Observatory and lead author of the study was quoted as saying, “The sun continues to surprise us.”

She further added, “The solar wind can hit Earth like a fire hose even when there are virtually no sunspots.”

Earlier, the scientists supposed that the streams of energy mainly vanished as the solar cycle moved towards the minimum.

Co-author Janet Kozyra of the University of Michigan, said, “The new observations from last year are changing our understanding of how solar quiet intervals affect the Earth and how and why this might change from cycle to cycle.”

Research study details and observations by scientists
The research team for the present study included scientists from the National Oceanic and Atmospheric Administration (NOAA) and National Aeronautics and Space Administration (NASA).

The researchers compared measurements gathered from the current solar minimum interval, taken in 2008, with the measurements of the last solar minimum in 1996.

They found out that although the present solar minimum has lesser sunspots than any minimum in 75 years, the sun’s effect on Earth’s outer radiation belt was above three times more last year than in 1996.

It was discovered that the occurrence of high-speed streams during the solar minimum in 2008 is associated with the structure of the sun.

The latest research study has been published in the current issue of the Journal of Geophysical Research.