I'm wondered about how many people are imagining just positive outcomes, like the objectively best things that could happen if aliens are confirmed as being rea

I'm wondered about how many people are imagining just positive outcomes, like the objectively best things that could happen if aliens are confirmed as being real. but, what if the scenario is more an actual "danger Will Robinson" situation, a true existential risk for humanity, like it is throughly exemplified in many scifi movies/books, let's mention just one truely terrible: "Dreamcatcher". What would you do then? Are somebody doing anything already? is it even possible to prevent a bad outcome? But you cannot unknow what you know.