What in the heck just happened to the sun?
In the early hours of Tuesday morning, our nearest star put on a show that won't be forgotten for a long, long time. Under the ever-watchful eyes of an armada of solar observatories, the sun unleashed an M2-class solar flare.
Keep in mind that an M2 flare, although powerful, is still only classed as a "medium" explosion. But there was nothing medium about this event.
Erupting from an active region of sunspots (sunspot complex 1226-1227) - where highly stressed and concentrated magnetic fields are forced through the solar surface (the "photosphere"), pushing the hot plasma aside, exposing the cooler plasma below the surface - the flare ejected a huge coronal mass ejection (CME).
A surprisingly large quantity of plasma didn't escape the gravitational pull of the sun, however, and was dragged back down as a vast cloud of cooler plasma, resembling the foaming, bubbly mess after popping a champagne cork.
The veil of darker plasma (it appears darker as it's cooler - at a temperature of around 80,000 K, compared with the surrounding million degree coronal plasma) expanded and appeared to cover half the sun's disk before being funneled along the powerful magnetic field lines, raining back into the photosphere. There even appeared to be sparks of sudden plasma heating as the huge blobs of gas impacted the dense plasma at the surface.
"I've never seen material released like this before," C. Alex Young, solar physicist of NASA's Goddard Space Flight Center, exclaims in the video depicting the event (below).
"It looks like somebody just kicked a giant clod of dirt up into the air."
The plasma that did escape the sun's gravity in the form of a CME is now racing through space at a breakneck speed of 1,100 kilometers per second (that's 2,448,000 miles per hour!). A rough calculation reveals the CME will reach the orbital distance of Earth in a little under 40 hours after the event and Spaceweather.com confirms that we may receive a "glancing blow," potentially causing geomagnetic storms (resulting in aurorae) at high latitudes later on Wednesday.
There's little cause for concern however. As dramatic at the explosion looks, it's only predicted to cause some minor interference to communications, satellites and potentially power grids if we do get hit. NASA states that the CME's impact is expected to be "fairly small."
Image: The eruption as seen by NASA's Solar Dynamics Observatory (SDO)> Credit: NASA/SDO/AIA