The sun unleashes its strongest glow this cycle

Yesterday the sun released a huge solar flare and it is on its way to Earth! It’s nothing to worry about as it’s not nearly as big as the Carrington Event of 1859, but it’s big enough to give us an amazing aurora.

Large solar flares occur periodically. Quite literally, because the sun goes through an eleven-year cycle of lower and higher activity. Right now the sun is near the maximum of a cycle, so we’re seeing a lot of sunspots and solar flares. When astronomers first studied the cycle, they could only measure the number of sunspots at any given time. Solar flares were largely invisible to early telescopes. But now, orbiting observatories like the Solar Dynamics Observatory allow us to capture images of solar flares in real time. Astronomers now categorize the strength of solar flares by the intensity of the X-rays they emit, known as their x class. The categories are numbered by power level, with each category being double the size of the previous one. For example, an X2 flare is twice as powerful as an X1 and half as strong as an X3.

This latest solar flare is rated X9, which is much stronger than most solar flares. But stronger events have reached Earth before. In 1989, an X15 event caused a regional blackout in Quebec. In November 2003, the sun released an X28 solar flare, but most of it missed Earth. The Carrington event of 1859 occurred before astronomers developed the x-class classification, but it is estimated to have occurred around X45. So this eruption is huge, but it will not seriously endanger our electrical infrastructure.

What it will deliver, however, is an aurora show. As the charged particles released by the eruption reach Earth’s magnetosphere, many of them will be captured by our magnetic field and spiral along the field lines into Earth’s atmosphere in the polar regions. The impact will cause the subtle and beautiful light shows known as aurora. If you live far enough from the equator, you might be able to see them in the next few days. To determine your chances, consult the National Oceanic and Atmospheric Administration’s Space Weather Prediction Center.