The sun is throwing stuff at us again.

A sunspot erupted Wednesday morning with a large, X-class solar flare that caused a wave of plasma called a Coronal Mass Ejection to shoot off the sun and come zooming toward Earth at the speed of 800 to 900 miles per second. 

This material follows on the heels of another CME on Tuesday, so there are actually two waves of charged solar stuff heading our way. 

If both these waves of solar material hit the Earth, scientists say you can expect to see some good auroras on Sept. 12 and 13.

And NASA scientists report another, smaller flare from the left corner of the sun Thursday morning.

"Hopefully that is a sign that some more interesting activity will come into view," said Alex Young, a heliophysicist at NASA's Goddard Space Flight Center in Greenbelt, Md.

In the video above, you can see some cool images of Wednesday's flare taken by the Solar Dynamic Observatory in a few different wavelengths of light. Note how the light follows loops out of the sunspot just before and after the flash of light. Those loops are actually magnetic fields that go out and then back in to the sunspot.

You may also notice that at the time of the flash, the area just to the right of the sunspot goes dark. That's called a "coronal dimming."

"Basically all this material is leaving the sun, so there is less stuff there, and less stuff to glow," Young said. "When you see a coronal dimming, that's a good sign that a CME is coming."

There is no reason to fear a CME, even one headed directly toward Earth. Our planet's atmosphere protects us from these occasional waves of radiation.

However, it is possible that some communication and GPS satellite operations will be temporarily out of service.

The satellites themselves have been built to withstand solar storms, but the signals they send back to Earth have to pass through a part of the upper atmosphere called the ionosphere, which gets all rattled up when a CME washes over it.

"When the sun erupts, it douses this region with extra energy and the GPS signal has trouble getting through it," said Joe Kunches, director of space weather services for the Colorado-based firm ASTRA. 

Kunches said these problems will not affect those of us who use GPS for directions on our mobile phones, however.

"Your cellphone GPS isn't really that accurate," he said.

But people who do precision agriculture and need to know within a few inches where they planted their seeds, for example, may have trouble with their GPS systems for a few hours to a few days.

Quelle: LAT

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