How can you be so sure of that? I think people don't have a very good grasp on the sheer immenseness of the universe. Sure, there's probably life out there. Although we can't be positive of that yet. Somebody has to be the first intelligent species in the universe. Maybe it's us. Probably not, but it's a possibility.

But intelligent life seems extremely rare. On earth, in 4 billion years only one species has developed the ability to go into outer space. And even then, we're far from being able to go to other solar systems and finding out if there's intelligent life there. And we very well may render ourselves extinct before we have the opportunity.

Like it or not, we are constrained by the speed of light. There is just no way to get to light speed without using an infinite amount of energy, which is impossible in our universe. And space is immense. There are billions of stars in just our galaxy alone in a disc 100,000 light years wide. Even if a species invested all its resources into exploring every planet in every solar system in the galaxy, it would take billions of years.