All scenarios / Space
Solar Superstorm
The Sun sneezes. Every power grid catches a cold.
What it is
A solar superstorm is a huge eruption from the Sun, usually a coronal mass ejection, that slams into Earth's magnetic field. In 1859 the Carrington Event set telegraph wires on fire. An event that size today could induce currents strong enough to damage high-voltage transformers, take out satellites and disrupt GPS and the internet.
Why it ranks where it does
Our score moves with NOAA's live planetary K-index, which measures geomagnetic activity. A reading of Kp 9, the top of the scale, would push this scenario up sharply. Estimates of the chance of a Carrington-class storm range from roughly 1% to 12% per decade. One study estimated that a severe storm could leave 20–40 million people without power for up to two years and cost $0.6–2.6 trillion.
Evidence on the board
- Live: NOAA planetary K‑index. A Carrington‑class storm (Kp 9) would add sharply to this score. NOAA SWPC ↗
What the experts say
Space-weather researchers treat this as a serious infrastructure risk, but not an extinction risk. The Sun doesn't harm people directly through the atmosphere. The damage would land on the grid and electronics, and utilities can protect equipment if they get warning. That's why it stays in the low single digits.
What would move the number
Up
- A Kp 8–9 storm with grid disruption
- Large Earth-facing flares near solar maximum
Down
- Grid operators installing current-blocking protection for transformers
- Better forecasting from solar observatories
Live signals we track
The baseline above is set from the evidence as of October 13, 2026. On the live board, your browser adjusts it in real time using these feeds. Chatter can only nudge a score in proportion to its evidence, so attention alone can't make an unlikely scenario look likely.
- Public attention: daily Wikipedia pageviews for Carrington Event
- Public attention: daily Wikipedia pageviews for Geomagnetic storm
- Online chatter: Hacker News stories mentioning "solar storm" this week vs. the prior eight weeks
- Physical sensor: NOAA planetary K-index (geomagnetic storms)
Sources
- Moriña et al., PMC: probability of extreme space weather
https://pmc.ncbi.nlm.nih.gov/articles/PMC6936226/ - Planetary Society: Should you be worried about solar storms?
https://www.planetary.org/articles/should-you-be-worried-about-solar-storms - Jyothi 2021, SIGCOMM: Solar superstorms and the internet
https://ics.uci.edu/~sabdujyo/papers/sigcomm21-cme.pdf - NOAA SWPC
https://www.swpc.noaa.gov/
Baseline scores are an editorial threat index from 0 to 100 that combines current reporting with published expert estimates. They're meant for comparing risks, not as actuarial forecasts. See how the numbers work.