Marcin Frąckiewicz

In early July 2025 astronomers using the NASA‑funded ATLAS telescope in Chile discovered a hyper‑fast object now designated 3I/ATLAS—only the third confirmed interstellar body to enter our Solar System after ’Oumuamua and Borisov. Follow‑up astrometry shows an inbound velocity of ≈58 km s⁻¹ and an orbital eccentricity of ≈6.1, values far in excess of anything gravitationally bound to the Sun, proving an extrasolar origin. First photometric estimates put the nucleus at 9‑20 km—an order of magnitude larger than Borisov—and early images already reveal a developing coma and tail. Dynamical modelling by Oxford–Canterbury researchers traces its trajectory back to the Milky Way’s thick disc, implying the ice‑rich body may be ≥7 billion years old—much older than the Solar System itself. Although 3I/ATLAS will dive just inside Mars’ orbit on 30 October, it never comes closer than 1.6 au to Earth and poses no hazard. Instead it offers an unprecedented laboratory for studying planet formation chemistry beyond our neighbourhood, and it is galvanising plans for rapid‑response spacecraft such as ESA’s 2029 Comet Interceptor.