This could be the culprit responsible for 2012. Being an unknown type, it is capable of anything, including hurling a galactic wave our way at a predicatble time...

A mystery object near the centre of our galaxy is sending out powerful pulses of radio waves. It is unlike any known source. A team of astronomers led by Scott Hyman of Sweet Briar College, Virginia, detected the mysterious source using the Very Large Array radio telescope in New Mexico. The pulses are coming from a spot just to one side of the galactic centre. Each pulse lasts about 10 minutes, and they repeat regularly every 77 minutes. If, as the researchers think, the source is near the centre of the Milky Way, it would be one of the most powerful emitters in the galaxy. The shape and timing of the pulses rules out most known sources, such as radio pulsars (Nature, vol 434, p 50). The object could be a magnetar - a neutron star with an ultra-strong magnetic field. "Magnetars store plenty of energy to power the observed outbursts," says Hyman. Or it may be something entirely new. To find out more, the team is studying it using the Green Bank radio telescope in West Virginia, and hopes to use NASA's Chandra space telescope to see if it is also spitting out X-rays.

Source: New Scientist