September s Aurora . ... Credit Copyright: Yuichi Takasaka / TWAN / www.blue-moon.ca Explanation: September's equinox arrives today at 0905 UT. As the Sun crosses the celestial equator heading south, spring begins in the southern hemisphere and autumn in the north. And though the seasonal connection is still puzzling, both spring and autumn bring an increase in geomagnetic storms. ... NASA Web Site Statements, Warnings, and Disclaimers . NASA Official: Jay Norris. ...