This has been argue for many generations already. The main proof (from a Torah source) advanced in favor of intelligent life elsewhere in the universe is the pasuk in Shoftim (5:23) ?????? ?????? ????? ???????? ?’ ????? ?????? ?????????? ???? ??? ????? ????????? ?’ ????????? ?’ ??????????????
The Gemara in Moed Katan in discussing ???? says ???? ????? ???? ??? ??? ????? ????? ????? ??? ????? ??? ???? ????? ???????. So there is an opinion that it is a star. And the pasuk refers to ?????????? i.e. its inhabitants.
I believe (I’m saying believe in case I am misremembering) that R’ Soloveitchik said that it is plausible that there is other life because H’ wants to do chessed so why would the chessed be limited to the infinitesimally miniscule Earth. It’s likely that there is a lot of life out there – the more life = the more chessed that H’ can do. You can look this up in “The Rav Thinking Aloud” which I don’t currently have. (If I had it I would quote the relevant portion.)