The detection of “mini-moons”—small asteroids temporarily captured in orbit around Earth—will vastly improve our scientific understanding of asteroids and the Earth-Moon system, says a new review published in Frontiers in Astronomy and Space Science. These small and fast-moving visitors have so-far evaded detection by existing technology, with only one confirmed mini-moon discovery to date. The advent of the Large Synoptic Survey Telescope (LSST) will verify their existence and track their paths around our planet, presenting exciting scientific and commercial opportunities.