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48587
From: ryan, [DNS_Address]
Subject: auroras and more in the usa
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AURORAS (AND MORE) IN THE USA: On March 21st, a crack opened in Earth's magnetic field. Solar wind poured through the gap to fuel a G2-class geomagnetic storm. Auroras spilled across the Canadian border into the USA as far south as Colorado, Arizona and maybe even Texas. Michele Sadauskas was watching the show from Glidden, Wisconsin, when she remembered one of her golden rules of aurora photography: "Always turn around and look behind you!" she says. "There was STEVE, very bright and easy to see with the naked-eye." STEVE is the narrow purple pillar embedded in the broader glow of red and green auroras. At first glance, STEVE looks like an aurora, but it is not. The phenomenon is caused by ribbons of hot gas flowing through Earth’s magnetosphere at speeds exceeding 13,000 mph. Discovered less than 10 years ago, STEVE appears unpredictably during some geomagnetic storms. "Within only a couple of minutes, the pink-purple color was lost, and what remained was a wider red arc that stretched from east to west," says Sadauskas. She then witnessed another light that is not an aurora--the SAR arc:  This pure red band is a sign of heat energy leaking into the atmosphere from Earth's ring current system–a donut-shaped circuit carrying millions of amps around our planet. SAR arcs are yet another luminous phenomenon that can appear during geomagnetic storms alongside auroras. Always turn around! |
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[48588]
48588
From: Redhart, [DNS_Address]
Subject: Re: auroras and more in the usa
| cool stuff! |
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None
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