3.07.2012

MAJOR SOLAR FLARE TODAY

A CME propelled toward Earth by this morning's X5-class solar flare is expected to reach our planet on March 8th at 0625 UT (+/- 7 hr). Analysts at the Goddard Space Weather Lab, who prepared the CME's forecast track, say the impact could spark a strong-to-severe geomagnetic storm.



Such a CME could result in a severe geomagnetic storm, causing aurora at low latitudes, with possible disruption to high frequency radio communication, global positioning systems (GPS), and power grids.



 This flare was categorized as an X5.4, making it the second largest flare - after an X6.9 on August 9, 2011 --since the sun’s activity segued into a period of relatively low activity called solar minimum in early 2007. The current increase in the number of X-class flares is part of the sun’s normal 11-year solar cycle, during which activity on the sun ramps up to solar maximum, which is expected to peak in late 2013.

In association with these flares, the sun also expelled two significant coronal mass ejections (CMEs), which are travelling faster than 600 miles a second and may arrive at Earth in the next few days. In the meantime, the CME associated with the X-class flare from March 4 has dumped solar particles and magnetic fields into Earth’s atmosphere and distorted Earth's magnetic fields, causing a moderate geomagnetic storm, rated a G2 on a scale from G1 to G5.

Such storms happen when the magnetic fields around Earth rapidly change strength and shape. A moderate storm usually causes aurora and may interfere with high frequency radio transmission near the poles. This storm is already dwindling, but the Earth may experience another enhancement if the most recent CMEs are directed toward and impact Earth.

In addition, last night’s flares have sent solar particles into Earth’s atmosphere, producing a moderate solar energetic particle event, also called a solar radiation storm. These particles have been detected by NASA’s SOHO and STEREO spacecraft, and NOAA’s GOES spacecraft. At the time of writing, this storm is rated an S3 on a scale that goes up to S5. Such storms can interfere with high frequency radio communication.

Besides the August 2011 X-class flare, the last time the sun sent out flares of this magnitude was in 2006. There was an X6.5 on December 6, 2006 and an X9.0 on December 5, 2006. Like the most recent events, those two flares erupted from the same region on the sun, which is a common occurrence.

This eruption hurled a bright CME into space, shown here in a movie from the Solar and Heliospheric Observatory. Analysts at the Goddard Space Weather Lab estimate that the CME will reach Earth on March 8th at 0625 UT (+/- 7 hr), possibly triggering a strong-to-extreme geomagnetic storm.

No comments:

Post a Comment