INCOMING CME: Big sunspot 1402 erupted on Jan. 23rd, producing a strong M9-class solar flare and a fast-moving coronal mass ejection (CME). Analysts at the Goddard Space Weather Lab say the CME should reach Earth on Jan. 24th at 14:18 UT (+/- 7 hr) and Mars a little more than a day later. Strong geomagnetic storms are possible when the cloud reaches Earth. Our magnetic field is still reverberating from a CME impact on Jan. 22nd, so another blow could spark impressive auroras at high latitudes. Sky watchers in northern Europe, Canada, Alaska, and northern-tier US states such as the Dakotas, Minnesota and Wisconsin should be alert for Northern Lights.

DON'T MISS THE STORM: Would you like a call when geomagnetic storms are in progress? Storm alerts are available from http://spaceweathertext.com (text) and http://spaceweatherphone.com (voice).

GEOMAGNETIC MEGA-STORM: On Sept. 2nd, a billion-ton coronal mass ejection (CME) slammed into Earth's magnetic field. Campers in the Rocky Mountains woke up in the middle of the night, thinking that the glow they saw was sunrise. No, it was the Northern Lights. People in Cuba read their morning paper by the red glow of aurora borealis. Earth was peppered by particles so energetic, they altered the chemistry of polar ice.

Hard to believe? It really happened--exactly 150 years ago. This map shows where auroras were sighted in the early hours of Sept. 2, 1859:

Above: Aurora sightings, Sept. 2, 1859. Image courtesy J.L. Green, NASA

As the day unfolded, the gathering storm electrified telegraph lines, shocking technicians and setting their telegraph papers on fire. The "Victorian Internet" was knocked offline. Magnetometers around the world recorded strong disturbances in the planetary magnetic field for more than a week.

The cause of all this was an extraordinary solar flare witnessed the day before by British astronomer Richard Carrington. His sighting marked the discovery of solar flares and foreshadowed a new field of study: space weather. According to the National Academy of Sciences, if a similar flare occurred today, it would cause $1 to 2 trillion in damage to society's high-tech infrastructure and require four to ten years for complete recovery.

A repeat of the Carrington Event seems unlikely from our low vantage point in a deep solar minimum--but don't let the quiet fool you. Strong flares can occur even during weak solar cycles. Indeed, the Carrington flare itself occured during a relatively weak cycle similar to the one expected to peak in 2012-2013. Could it happen again? Let's hope not.

The "Let's hope not" link above leads to a January 21, 2009 story regarding the release of a NASA-funded study by the National Academy of Sciences entitled Severe Space Weather Events—Understanding Societal and Economic Impacts. In the 132-page report, experts detailed what might happen to our modern, high-tech society in the event of a "super solar flare" followed by an extreme geomagnetic storm. I urge you to read it. - Dave