NOAA map for August 4 depicting the size of the aurora.

Aurorae and meteors light up the sky this week. Let’s discuss the unusually low curtains of light first, and then you can skip below the fold for our annual August meteor shower.

Astronomical sad face: Washington is just a smidge too low in latitude to be seeing some incredible sky action this week, but let’s talk about it anyway. Some incredible aurorae have been hitting the poles; typically, aurorae can be seen only in the most northern and southern latitudes (Iceland is a great place to see them), but some major solar activity is bringing it well down into the States. In the map at the right, from the National Oceanic and Atmospheric Administration, the primary aurora activity is still over Alaska and northern Canada, but the edges actually stretch all the way down to New York, Pennsylvania, and even West Virginia. Continued activity means we’ll see more aurorae tonight and tomorrow, and even just getting the mere edges of an aurora down here is pretty spectacular. Tell your friends to the north to Look Up.

So what is aurora and why is it traveling so far from the poles? Aurorae are the visual effects of solar activity impacting Earth’s magnetic field. For example, on Sunday and again on Tuesday, the Sun let loose some strong coronal mass ejections (CMEs). Scientists believe CMEs are the result of the “lines” in the Sun’s magnetosphere realigning or “snapping” back together, resulting in a sudden release of energy. If the CME is directed towards Earth, high energy particles will ride the solar wind until it reaches us a couple days later, ionizing the nitrogen and oxygen in the upper atmosphere. Then these molecules, in their excited state, will get swept up in our magnetic field, concentrating them at either pole and becoming, usually, red and green curtains of light. Keep reading for an incredible video of Sunday’s CME.