The thought I've been having lately... for there to be other intelligent life in the universe, a host planet would only need to support life for about as long as our own has. In that time, we've come very close to creating self-aware AI. AI does not have the same sort of environmental restrictions to survive.

So long as there's been organic life for long enough to create artificial life on some other planet at some point during the history of the universe, it's practical to think that "life" could be present on a wide range of planets - much wider than the typical "goldilocks" planets to which we currently focus our interest.

There's a spider in my shower right now. I see it every time I go to the bathroom. I have a few choices...

1. Leave it be
2. Kill it
3. Carry it to the outdoors

My intention is always 3, but the shower is located in the basement and as soon as I'm done relieving myself I forget about my thought experiment and go about the rest of my day, failing to bring a suitable vessel back to rescue the spider.

Then I started to realize that perhaps 3 might even be inconveniencing the spider. There are no predators in its current location (other than me), and it seemingly has a source of food (the drain?) since it's sustained itself for at least a month.

I don't regularly use that shower. If my wife would happen to need it and I forget to carry out 3 by then... unfortunately for the spider, option 2 is suddenly in play.

Point being I imagine intelligent life capable of traveling the universe may treat us in much the same way. We're probably not really worth their time. If we become worth their time, it's likely because they need our resources. That might be a problem for us..

I've said it before, but we always seem to assume aliens are organic life. We're knocking on the door of creating self-aware AI technology here on Earth. it's at least plausible that some other civilization was able to accomplish that (for better or worse) at some point throughout the history of the universe.

Those 'aliens' would not necessarily be constrained to the goldilocks type planets we assume may be able to support 'life'. At that point, the math to support the possible existence of other civilizations becomes even more favorable.