Solar activity weakest in a century

Last Updated: Wednesday, December 25, 2013 - 14:45

New York: The Sun is at its weakest in 100 years despite being at the peak of its 11-year cycle, scientists have found.

Scientists think this could be the reason why the solar storms that have erupted during Solar Cycle 24 - the current solar cycle which began in 2008 - have caused relatively fewer problems on Earth.
Sun is now at "solar maximum," the peak phase of its 11-year activity cycle.
However, researchers said this solar max is weak and the overall current cycle conjures up comparisons to the famously feeble Solar Cycle 14 in the early 1900s, `SPACE.Com` reported.

"None of us alive have ever seen such a weak cycle. So we will learn something," Leif Svalgaard of Stanford University said.

Researchers said the powerful coronal mass ejections (CMEs) have rarely been seen during Solar Cycle 24, even though the total number of CMEs hasn`t dropped off much.

These CMEs can trigger geomagnetic storms, which in turn can disrupt radio communications, Global Positioning System (GPS) signals and power grids.
The explanation lies in the reduced pressure currently present in the heliosphere, a vast region of space surrounding the Sun.

This lower pressure has allowed CMEs to expand greatly as they cruise through space, researchers said.

On average, Solar Cycle 24 CMEs are 38 per cent bigger than those measured during the last cycle a difference with real consequences for Earth, the report said.

Scientists also believe this weaker solar activity could be the reason why relatively few super-fast solar energetic particles or SEPS have been measured in Earth`s neighbourhood during the current cycle.

First Published: Wednesday, December 25, 2013 - 14:45
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