Thread by @mcnees

The first solar flare observations were made #OTD in 1859 by Carrington & Hodgson, preceding one of the largest geomagnetic storms on record. Both amateur astronomers made their observations independently, and published them simultaneously in MNRAS.
adsbit.harvard.edu/cgi-bin/nph-ia…

The solar storm that followed was one of the most intense on record. Auroras were reported all over the world and there were mass telegraph outages. Currents induced in the telegraph lines were strong enough to melt contacts, shock operators, and set some kinds of paper on fire.

A “Carrington-class” solar storm occurred in 2012, but the coronal mass ejection from that one just missed the Earth.
Image: NASA/STEREO

At some point it will happen again, and it won’t miss. But the infrastructure we rely on now is much more susceptible than it was in 1889. The National Academy of Sciences says the economic impact of a modern-day 'Carrington Event' could top $2 trillion.
science.nasa.gov/science-news/s…

As global disasters go, it will be one of the prettier ones. The aurora will be dazzling and bright enough for you to read a book by; birds will think day is here. But telecoms will be down for a while, and there’s a pretty good chance your power grid will collapse.
Image: NAS

A great post by @BadAstronomer, from a few years back, on the near-miss in 2012.
slate.com/blogs/bad_astr…

Anyway, happy Saturday evening!