A recently discovered near-Earth asteroid, dubbed 2024 YR4, is making headlines because of the slim possibility that it could impact Earth on Dec. 22, 2032. Early observations suggest that it has about a 1% chance of colliding with our planet. So why all the fuss?
2024 YR4 is garnering so much attention because of more than 37,000 near-Earth asteroids already discovered, it is the only one with more than a 1 in 1,000 chance of impact. “It is rare to have an asteroid with a non-zero probability of hitting Earth,” said Heidi Hammel, Vice President for Science at the Association of Universities for Research in Astronomy and Vice President of the The Planetary Society’s board of directors.
To put it into context, 2024 YR4 has a Torino scale rating of as high as 3. The Torino Impact Hazard Scale ranges from 0 (no chance of impact) to 10 (certain impact likely to cause planetwide devastation). Ratings of 1 are fairly common among newly discovered asteroids, but follow-up observations have always reduced that rating to 0. Asteroid 2024 YR4’s rating of 3 is the second-highest an asteroid has ever reached. The only asteroid ranked higher was Apophis, discovered in 2004 and rated 4, but subsequently downgraded to 1 and then 0.
Right now, ESA estimates that 2024 YR4’s diameter is in the range of 40-100 meters (around 130-330 feet). If it did collide with Earth, an impactor of that size could cause an explosion in the atmosphere or even an impact crater, either of which could cause serious, even devastating, damage on the ground.