Wednesday, March 7, 2012

A Solar Storm Should be Hitting Earth About Right Now

From NASA: The sun erupted with one of the largest solar flares of this solar cycle on March 6, 2012 at 7PM EST. 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.

This movie of the March 6, 2012 X5.4 flare was captured by the Solar Dynamics Observatory (SDO) in the 171 Angstrom wavelength. One of the most dramatic features is the way the entire surface of the sun seems to ripple with the force of the eruption. This movement comes from something called EIT waves – because they were first discovered with the Extreme ultraviolet Imaging Telescope (EIT) on the Solar Heliospheric Observatory. Since SDO captures images every 12 seconds, it has been able to map the full evolution of these waves and confirm that they can travel across the full breadth of the sun. The waves move at over a million miles per hour, zipping from one side of the sun to the other in about an hour. The movie shows two distinct waves. The first seems to spread in all directions; the second is narrower, moving toward the southeast. Such waves are associated with, and perhaps trigger, fast coronal mass ejections, so it is likely that each one is connected to one of the two CMEs that erupted on March 6. Credit: NASA/SDO/AIA

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