How do you know? In the past people would have said, there can be no life there at all. And now people think they have evidence. The universe is so vast, and we

How do you know? In the past people would have said, there can be no life there at all. And now people think they have evidence. The universe is so vast, and we are blind to most of it, why should life be so sparse? It's the norm, not the exception, is that unlikely? How can you be so certain. Seems people so sure of life outside earth or not need it to be that way. Why can't people be okay with it just being ambiguous for now...