Where is Voyager Headed? Where did 3I/ATLAS Come From?

We've been visited by at least three interstellar objects — and we've sent five spacecraft on paths that will eventually leave the solar system. In this video I switch from a heliocentric view to a galactocentric one to show what these trajectories really look like as the Sun moves through the Milky Way, then fast-forward to see which stars our probes will (and won't) pass near.

We also rewind the clock on ʻOumuamua, Borisov and 3I/ATLAS to explore what we can — and can't — say about where they came from, and why "alien tech" is the wrong kind of weird.

Sources and further reading

• Schönrich, Binney & Dehnen (2010), MNRAS
• Bailer-Jones & Farnocchia (2019), Spacecraft interstellar encounters — see also the Voyager and ʻOumuamua pages
• Bailer-Jones et al. (2018b), A&A 616, A37
• 1I/ʻOumuamua: arXiv:1809.09009
• 2I/Borisov: A&A 637, A31
• 3I/ATLAS: arXiv:2509.07678 and arXiv:2509.03361

The Milky Way stand-in uses the publicly available FIRE-2 cosmological zoom-in simulations (Wetzel et al. 2023, 2025) from the Feedback In Realistic Environments project, generated with the Gizmo code (Hopkins 2015) and the FIRE-2 physics model (Hopkins et al. 2018).