It was a stormy weekend, geomagnetically speaking, as solar flares sparked two coronal mass ejections (CME) last week, both heading straight for Earth. Fortunately, the relatively moderate CMEs caused little disruption as they plowed into Earth’s magnetosphere, other than a glorious display of auroras. The northern lights could be seen as far south as Iowa, Nebraska and Maryland.

The solar show began on June 13 as the first flare erupted from an area of increased solar activity lovingly called AR 1504, a hotspot of action that rotated around to face the Earth on June 10. The second CME-causing solar flare leaped from AR 1504  on June 14. Both CMEs collided with Earth on Saturday, June 16, slightly “warping” or flattening the planet’s protective outer “shell” known as the magnetosphere, leading to the dramatic display of northern and southern lights.

CMEs are gigantic clouds of plasma set off by solar flares and can potentially cause catastrophic damage, disrupting or destroying satellites and bringing down electronics and electric grids for weeks or months. CMEs this debilitating are created from X-class solar flares, the strongest class of solar eruption. Next are M-class, or medium flares, and then C-class, the weakest. Last week’s flares from AR 1504 were M-class and never expected to do much damage, even though they both smashed into the Earth pretty much head-on. Scientists say both CMEs were relatively slow-moving, lessening their potential to cause damage. The first CME traveled to Earth at about 375 miles per second, with its counterpart traveling at approximately 800 miles per second (San Francisco to L.A. and back in one second!).

While scientists aren’t currently anticipating the imminent approach of any more CMEs, they’re keeping an eye out on the “rapidly evolving” AR 1504 sunspot:

“Solar Radiation Storm levels have returned to background levels after the small S1 (Minor) storm observed on June 16,” report officials at the Space Weather Prediction Center. “No further activity is currently expected, but Region 1504 is still present and harbors a slight chance for subsequent activity.”

Celebrate the Summer Solstice – Live Solar Show

The SLOOH Space Camera will broadcast a live solar show tonight starting at 7 p.m. EDT (2300 GDT). The show will give viewers a chance to examine recent solar activity and celebrate the start of summer in the Northern Hemisphere. Tune in!

Main image credit: Preserved Light by Caillum Smith, courtesy Flickr

Video credit: NASA SDO