All scenarios / Space
Asteroid Strike
Worked great on the dinosaurs.
What it is
An asteroid strike is the dinosaurs' apocalypse. A rock around 10 km across hit Mexico 66 million years ago and ended the Cretaceous period. Smaller impacts happen more often: an asteroid around 140 m across hits roughly every 20,000 years, a 1 km asteroid about every 700,000 years, and a 10 km giant roughly every 100 million years.
Why it ranks where it does
This is one of the best-monitored risks on the board. NASA says more than 90% of near-Earth asteroids larger than 1 km have been found, and no known asteroid larger than 140 m has a significant chance of hitting Earth in the next 100 years. Our score uses NASA's live close-approach feed and a prediction market on a meteor strike of 10 kilotons or more this year.
Evidence on the board
- Live: NASA's close‑approach feed for the next 7 days. Nothing known is on course for a civilization‑ending hit. NASA CNEOS ↗
What the experts say
Toby Ord estimates the existential risk from asteroids at about 1 in 1,000,000 per century. In 2022 NASA's DART mission showed that we can nudge an asteroid's orbit. This is one of the few apocalypses that humanity has already practised preventing.
What would move the number
Up
- Discovery of a large object with a non-trivial impact probability
- Gaps in sky-survey coverage
Down
- NEO Surveyor and other surveys finding more of the remaining small asteroids
- Further deflection tests
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.
- Prediction market: Major meteor strike (10kt+) in 2026, 6.5% at snapshot Polymarket ↗
- Public attention: daily Wikipedia pageviews for Impact event
- Online chatter: Hacker News stories mentioning "asteroid" this week vs. the prior eight weeks
- Physical sensor: NASA near-Earth object close approaches
Sources
- NASA: Asteroid facts
https://science.nasa.gov/solar-system/asteroids/facts/ - NASA: Planetary defense overview
https://science.nasa.gov/planetary-defense-overview/ - NASA: 10 things to know about planetary defense
https://science.nasa.gov/solar-system/10-things-you-should-know-about-planetary-defense/ - Planetary Society: Will an asteroid hit Earth?
https://www.planetary.org/articles/will-an-asteroid-hit-earth - 80,000 Hours: Toby Ord's existential risk estimates
https://80000hours.org/articles/existential-risks/ - NASA CNEOS
https://cneos.jpl.nasa.gov/sentry/ - Polymarket: Major meteor strike (10kt+) in 2026
https://polymarket.com/event/major-meteor-strike-10kt-in-2026
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.