Until proven otherwise, belief that life exists elsewhere in this solar system remains the only secularly accepted religion in Western culture (with the possible exception of Buddhism and perhaps Islam).
Every new discovery that we make in astrophysics increases the odds against the possibility of life (and certainly intelligent life) existing anywhere else in the universe.
Humm, let’s see if as you say there is only life on this planet, we need to do some calculations.
In one quadrant of the universe so far imaged there are something like 52 billion galaxies or all four at the same rate would be 208 billion galaxies each with around 300 billion stars 208x300=624,000,000,000,000,000,000 stars in all.
So you are saying that G-d got lucky in one of those galaxies, on one of those stars, on the fringe of that one galaxy, on one planet?
Boy! Those are such long odds, its a wonder G-d even bothered rolling the dice ...
Actually, Judaism has little opinion on the issue of intelligent life elsewhere.
The Rebbe was of the opinion that it was possible.
There is some argument to be made that the Book of Judges 5:23, Devorah the prophetess sings about the victory of Barak over Sisera. In her song, she says, “Cursed be Maroz! Cursed, cursed be its inhabitants, says the angel of G-d!”
The Talmud says that Maroz is a star or planet.
Entities from heavenly bodies had also come to help the Israelites, as Devorah stated just one verse earlier,”From the heavens they fought, the stars from their orbits…”.
Maroz, however, which was the dominant star of Sisera, apparently did not come to their aid. And so, General Barak penalized Maroz—and its inhabitants.
Does life exist? That wouldn't shock me. Particularly if it's not "as we know it" - say, silicon based instead of carbon-based.
Is it intelligent? As we define it? I'd call that "A whole lot less likely".
Will we ever find intelligent life? And communicate with it? I'd call those chances "Slim to none, and Slim just left town". Figure that enormous times and distances work against any life forms (intelligent or not) travelling across space. Additionally, if there is "intelligent" life, what makes us think that it wants to communicate with us? For instance - you're aware of the ants in your driveway, but you don't stand around outside trying to talk to them.