Sunspot Grows to 20 Times Size of Earth

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Sunspot Grows to 20 Times Size of Earth

By Robert Roy Britt

Senior Science Writer

posted: 05:10 pm ET

23 July 2004

http://www.space.com/scienceastronomy/hugesunspots_040723.html

 

A sunspot group aimed squarely at Earth has grown to 20 times the

size of our planet and has the potential to unleash a major solar

storm.

 

The amorphous mix of spots, together called Number 652, has been

rotating across the Sun and growing for several days. On Friday, it

sat at the center of the solar disk.

 

Sunspots are areas of intense magnetic energy, cooler and darker

than the surrounding surface of the thermonuclear furnace. Sometimes

the magnetic fields let loose and huge amounts of radiation and

charged particles are hurled into space.

 

The Sun's last bout of intense storminess occurred last fall, when a

string of 10 major flares over two weeks knocked out satellites,

damaged others, and forced the FAA to reroute airlines away from

exposed polar routes.

 

No one can say if this sunspot group will let loose with a major

storm, but it has the characteristics of a potentially big event.

 

"The implications of this spot have scientists on the edge of their

seats," NASA said in a statement Friday. "If the active region

generates coronal mass ejections (CMEs), massive explosions with a

potential force of a billion megaton bombs, it will be a fairly

direct hit to Earth and its satellites and power grids."

 

The Sun is now in a generally quiet period of a well-known 11-year

cycle of activity. But sunspots and flares can occur at any time.

Scientists do not fully understand why the spots appear or how they

erupt.

 

The sunspot is clearly visible from Earth without a telescope. But

don't look at the Sun without a proper, safe filter or other viewing

technique, or permanent eye damage can result.