Close approach of asteroid 2024 ON

Asteroid 2024 ON will safely fly past Earth on 17 September 2024 at 10:17 UTC (12:17 CEST). It is between 210 and 500 m across and will briefly pass within one million km of our planet. 

This asteroid poses no danger to Earth, but objects such as 2024 ON are a central focus of planetary defence efforts.

Large asteroids are few in number and easier to spot when they are far away from Earth, while there are many small asteroids that evade discovery but burn up harmlessly in Earth's atmosphere.

Asteroids that are tens or a few hundreds of metres across, like 2024 ON, may only be discovered a few weeks or months before they pass Earth but are large enough to cause significant damage if they impact our planet.

It is asteroids like these that Earth's planetary defenders are working hard to detect, catalogue and track by constructing custom asteroid-hunting telescopes and carrying out daily sky surveys.

Find out more about asteroids and ESA's Planetary Defence activities.