What's up in space

CHANCE OF STORMS: NOAA forecasters estimate a 65% chance of polar geomagnetic storms on March 15th when a CME might deliver a glancing blow to Earth's magnetic field. The CME was launched by a filament of solar magnetism that erupted on March 12th. High-latitude sky watchers should be alert for auroras when the cloud arrives.  The source of the explosion was active region AR1690 on the sun's central meridian. Although AR1690 is almost directly facing our planet, debris from the blast will mostly miss Earth. A CME produced by the explosion is traveling north of the sun-Earth line. Nevertheless, the southern fringe of the CME might hit Earth's magnetic field on March 15th.

THE COMET SHOW BEGINS: Last night, March 12th, a rare meeting occured in the sunset sky. Comet Pan-STARRS (C/2011 L4) was only a few degrees away from the exquisitely-slender crescent Moon. Brian Klimowski sends this picture from the countryside near Flagstaff, Arizona:

"Beautiful show this evening!" says Klimowski. "I took the photo from an altitude of about 9500 feet in the San Francisco Peaks near Flagstaff. A 1-second exposure with my Canon digital camera easily revealed the comet."

Because of the sunset glow, Comet Pan-STARRS remains at the lower limit of naked-eye visibility. A small number of observers have reported seeing the comet with averted vision but, for the most part, binoculars are required. The situation will improve in the nights ahead as Comet Pan-STARRS moves away from the sun into darker skies. Later this week it might be possible to walk outside after nightfall, look west, and see the comet with the unaided eye. If you would like to try tonight, look for Comet Pan-STARRS directly underneath the waxing crescent Moon: sky map.

The show is just getting started. Stay tuned! More: NASA video, 3D orbit, ephemeris, light curves.     www.spaceweather.com