These Solar flares are also the cause behind the beautiful northern lights (aurora).

Solar Flare

Solar Flares (large bursts of gas from the sun) happen all the time.  Approximately every 11 years or so, the sun seems to have an extra large burst of activity.  2012 was thought to be the end of the next 11 cycle where sun spots would start to appear as the tell tale sign of extra solar activity - i.e. solar flares (which stay close to the surface of the sun) and Coronal Mass Ejections (which can travel millions of miles out into space).  However, NASA scientists have said recently that it looks like the next cycle will come around in 2013 and not 2012.

Coronal Mass Ejection

Coronal mass ejections (or CMEs) are huge bubbles of gas threaded with magnetic field lines that are ejected from the Sun over the course of several hours. Although the Sun's corona has been observed during total eclipses of the Sun for thousands of years, the existence of coronal mass ejections was unrealized until the space age. The earliest evidence of these dynamical events came from observations made with a coronagraph on the 7th Orbiting Solar Observatory (OSO 7) from 1971 to 1973. A coronagraph produces an artificial eclipse of the Sun by placing an "occulting disk" over the image of the Sun. During a natural eclipse of the Sun the corona is only visible for a few minutes at most, too short a period of time to notice any changes in coronal features. With ground based coronagraphs only the innermost corona is visible above the brightness of the sky. From space the corona is visible out to large distances from the Sun and can be viewed continuously. The animated sequence of images at the top of this page were obtained with the High Altitude Observatory's coronagraph on the Solar Maximum Mission in April of 1980.

solar flares

Solar flares happen when when energy stored in twisted magnetic fields is suddenly released causing an explosion of plasma shot up from the sun's surface.  Apparently the energy from these solar flares can be enough to produce 100 billion atomic bombs.  But it's nothing to be concerned about because this all happens low down in the sun's corona (outer surface).  This burst of electromagnetic radiation produced from these solar flares includes radio waves, x-rays and gamma-rays.  Sometimes there will be a CME (CORONAL MASS EJECTIONS)associated with solar flares.  Solar Flares and CME's can happen independently of each other.

The Truth about 2012 from NASA Lunar Science Institute on Vimeo.

NASA's David Morrison, expert on Earth impact hazards and currently Interim Director of the NASA Lunar Science Institute, speaks on what are the risk to Earth in 2012. He addresses misconceptions related to the year 2012, Earth crossing objects, planetary alignment, and related myths like Nibiru. 

For more information on this topic, please see
 astrobiology.nasa.gov/ask-an-astrobiologist/intro/nibiru-and-doomsday-2012-questions-and-answers.