@robin_winters @gdinwiddie There are two logical reasons aliens might be hostile. 1) they see us as a threat. We might be one breakthrough away from near light speed spaceflight, and humans would spread like a plague if we got loose.

2) they want the planet. Habitable planets are rare, terraforming doesn't work well, and the easiest way to find habitable planets is to do large scale passive SETI and wait for some idiot to broadcast his presence.