Scouring others’ observations for new discoveries is actually common among astronomers:
1. In 2013, Rémi Soummer and colleagues reprocessed Hubble infrared data extending as far back as 1999. Where other scientists found nothing, Soummer’s team discovered five stars (including HD 141943, pictured at top of the page) with surrounding dust disks — the breeding grounds of planets.
2. When looking through 15-year-old radio data from several observatories in 2013, astronomers found clumpy segments along a ring shape in our galaxy; when they searched for it in visible light, they came up empty. Francesco de Gasperin and colleagues believe they’ve spied an old stellar explosion whose material has mostly dispersed, making it invisible in optical light but leaving behind radio imprints at the site.