Hundred-metre wide asteroid rises to top of impact risk lists after being spotted in December by automated telescope

A 100 metre-wide asteroid has triggered global planetary defence procedures for the first time after telescope observations revealed it has a chance of colliding with Earth in 2032.

Asteroid 2024 YR4 was spotted by an automated telescope in Chile on 27 December last year but has since risen to the top of impact risk lists maintained by the US and European space agencies.