Comment It's about Time (Score 1) 686
The universe is indeed full of life. And life becomes intelligent and thrives. And every ten million years or so...
Gets hit by a meteor.
Another meteor.
Comet this time.
Solar flare.
Nearby nova, supernova or far-away hypernova fries them.
Ice age.
Heat age.
Bacteria this time.
Here comes some volcanoes.
Food poisoning.
Drought.
Floods come.
War.
Mutations.
And finally, time happens, if nothing else. The universe is full of life - BUT NOT ALL AT THE SAME TIME, and not all at a time that happens, in each case, to emit radiation that arrives at our sensors at this tiny opportunity of ours to detect it. The universe is full of little flashes of life in the dark that wink on and off like fireflies, and we can't possibly see them - in time. We are alone, and we had better damned well take care of ourselves.
PS: what makes people think that successful life stays on a planet? That's a surefire way to die, by the list of events above. Successful life gets off the planet, builds terraria in orbit, and sends some off into the darkness to spread and survive the death of the home planet. At the very least. At the most, they spread into adjacent universes or dimensions. Or even travel in time, whatever that is. Life, successful life that lives a long time, grows up and gets out of the petri dish. Or dies with all the other failed flashes of life.