Above: A photo of the sun on Oct. 31, 1903, from the Royal Observatory in Greenwich. [ref]
Don't let Solar Minimum fool you.
The sun can throw a major tantrum even during the quiet phase of the 11-year solar cycle. That's the conclusion of
a new study published in the July 1st edition of the
Astrophysical Journal Letters.
"In late October 1903, one of the strongest solar storms in modern history hit Earth," say the lead authors of the study, Hisashi Hayakawa (Osaka University, Japan) and Paulo Ribeiro (Coimbra University, Portugal). "The timing of the storm interestingly parallels where we are now-near Solar Minimum just after a weak solar cycle."
The 1903 event wasn't always recognized as a great storm. Hayakawa and colleagues took an interest in it because of what happened when the storm hit. In magnetic observatories around the world, pens scrabbling across paper chart recorders literally flew offscale, overwhelmed by the disturbance. That's the kind of thing superstorms do.
So, the researchers began to scour historical records for clues, and they found four magnetic observatories in Portugal, India, Mexico and China where the readings were whole. Using those data they calculated the size of the storm.
Comment: Storm Isaías leaves nearly 500,000 without electricity in Puerto Rico - flooding and landslides also hit the island