Well, I think everyone is pretty sure that there is no intelligent alien life in our solar system, since everything we can see is either a rock, or ball of gas

Well, I think everyone is pretty sure that there is no intelligent alien life in our solar system, since everything we can see is either a rock, or ball of gas or ice. The only things we can detect outside the solar system are stars and maybe some of their planets, or things much bigger than stars, all of which we are also pretty sure are naturally occurring given their scale. That doesn't leave a lot else that we have observed outside of this Oumuamua object and maybe a few stray radio signals that we can't account for.