A year ago yesterday, lightning bolts across parts of Europe and Asia changed direction. The switch was caused by an exploding star two billion light-years away — the possible birth of a black hole.

Gamma-ray burst GRB 221009A was first seen by space telescopes. They recorded a blast of gamma-rays, the most energetic form of light. The outburst lasted for more than five minutes — far longer than most outbursts. And it was the most powerful ever seen. Astronomers nicknamed it the BOAT — brightest of all time.

Other telescopes in space and on the ground recorded the event in every form of light. It was even bright enough to see through small telescopes.

Charged particles from the outburst flooded Earth’s upper atmosphere. They disrupted part of the ionosphere — a layer with an electric charge. That caused the ionosphere to expand, and knocked out some radio communications. Particles that flew deeper into the atmosphere caused changes in lightning activity, and even set up mild currents in the ground.

The outburst probably erupted when the core of a huge star collapsed to form a black hole. Magnetic fields created a swirling disk around the black hole. The disk powered enormous beams of energy that sliced into space from the poles of the dying star. Earth lined up along one of those beams, so we got a powerful dose of energy — announcing the birth of a black hole.
 

Script by Damond Benningfield

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