WATCH: The Solar Eruptions That Caused Today’s Spectacular St. Patrick’s Day Auroras

By Tom Yulsman | March 17, 2015 8:24 pm
St. Patrick's Day

The auroral display at Donnelly Creek, Alaska, photographed at 1:30 a.m., March 17, 2015, by Sebastian Saarloos. (Source: NASA Goddard Space Flight Center)

Curtains of hyper-luminous green, white, purple and red light glittered in the skies around the world today as a result of a severe geomagnetic storm caused by two massive explosions on the Sun.

These St. Patrick’s Day auroral displays started early on Tuesday, March 17th, and they are predicted to continue overnight.

St. Patrick's Day

The two eruptions from the Sun, called coronal mass ejections, responsible for the major geomagnetic storm here on Earth on March 17, 2015, are see in this animation created using data from the SOHO spacecraft. (Source: SOHO/

The video above, from the SOHO spacecraft, shows the two coronal mass ejections from the Sun, or CMEs, responsible for the auroral fireworks. 

These massive explosions of material occurred on Sunday. (The black circle is called an “occulting disk.” It blocks out the extremely bright, obscuring light of Sun and its inner atmosphere so that CMEs can be seen more clearly.)

CMEs are gargantuan bubbles of gas many times larger than the Earth that explode from the Sun. Threaded with magnetic field lines, Sunday’s CMEs traveled across the 92,960,000 miles separating us from the Sun and seriously jostled the Earth’s protective magnetic field, triggering the geomagnetic storm responsible for the auroral displays.

Today’s geomagnetic storm was recorded at the G4 level. This is on a scale that goes from G1 to G5. That makes it the most powerful one since 2013.

G4 storms are characterized as “severe” events, according to the Space Weather Prediction Center, and they are capable of producing a good deal of mayhem, in addition to beautiful auroral displays:

Power systems: Possible widespread voltage control problems and some protective systems will mistakenly trip out key assets from the grid.

Spacecraft operations: May experience surface charging and tracking problems, corrections may be needed for orientation problems.

Other systems: Induced pipeline currents affect preventive measures, HF radio propagation sporadic, satellite navigation degraded for hours, low-frequency radio navigation disrupted, and aurora has been seen as low as Alabama and northern California (typically 45° geomagnetic lat.).

Luckily, as I’m writing this post, no significant impacts like that have been reported.

So with that comforting news in mind, enjoy these auroral images:

CATEGORIZED UNDER: Astronomy, Earth Science, select, Sun, Top Posts
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ImaGeo is a visual blog focusing on the intersection of imagery, imagination and Earth. It focuses on spectacular visuals related to the science of our planet, with an emphasis (although not an exclusive one) on the unfolding Anthropocene Epoch.

About Tom Yulsman

Tom Yulsman is Director of the Center for Environmental Journalism and a Professor of Journalism at the University of Colorado, Boulder. He also continues to work as a science and environmental journalist with more than 30 years of experience producing content for major publications. His work has appeared in the New York Times, Washington Post, Audubon, Climate Central, Columbia Journalism Review, Discover, Nieman Reports, and many other publications. He has held a variety of editorial positions over the years, including a stint as editor-in-chief of Earth magazine. Yulsman has written one book: Origins: the Quest for Our Cosmic Roots, published by the Institute of Physics in 2003.


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