giovedì 15 giugno 2017

spaceweather.com

NASA TRIES AGAIN TO PRODUCE ARTIFICIAL CLOUDS: Tonight, June 15th, NASA will attempt to overcome a series of weather and hazard-related postponements to launch a sounding rocket over the east coast of the USA.  The Terrier-Improved Malemute rocket will blast off between 9:05 and 9:20 p.m. EDT and release a network of red and blue-green vapors more than 100 miles high. Tracking the motions of the colorful gases will help researchers study the dynamics of Earth's ionosphere. The vapor tracers may be visible from New York to North Carolina and westward to Charlottesville, Virginia.
A HOLE IN THE SUN'S ATMOSPHERE: A large hole has opened in the sun's atmosphere and it is turning toward Earth. NASA's Solar Dynamics Observatory is monitoring the structure, shown here in an extreme ultraviolet image taken on June 13th:
This is a coronal hole (CH) -- a region where the sun's magnetic field peels back and allows solar wind to escape. A fast-moving stream of solar wind from this coronal hole is expected to arrive on June 16th, possibly sparking G1-class geomagnetic storms. High-latitude sky watchers should be alert for auroras, especially in the southern hemisphere where autumn darkness favors visibility.

Forecasters note that this stream is unusually fast with wind speeds as high as 700 km/s. Moreover, it is threaded with "negative polarity" (south-pointing) magnetic fields. Such fields do a good job connecting to Earth's magnetosphere and energizing geomagnetic storms. Free: Aurora Alerts

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