Translate

Thursday, July 18, 2013

A space weather forecast


AURORAS OVER YELLOWSTONE

 A CME swept past Earth on July 13th. The impact was gentle and did not spark a geomagnetic storm. However, south-pointing magnetic fields in the CME's wake had greater effect. The "negative Bz" opened a crack in Earth's magnetosphere, allowing solar wind to pour in and fuel high-latitude auroras. Zack Clothier photographed these over Yellowstone National Park on July 15th:
 
 

"At about midnight on July 15th, just as the moon was setting, the lights came alive over White Dome Geyser in the Lower Geyser Basin of Yellowstone National Park," says Clothier. "While I was standing there in the darkness a coyote started howling nearby, adding to the already eeriness of the scene. If you look closely you can see a meteor streaking down towards the geyser, to the left of the Milky Way."

More scenes like this are possible on July 18th when a solar wind stream is expected to hit Earth's magnetic field. NOAA forecasters estimate a 50% chance of geomagnetic storms.

No comments: