Sure

Pope Francis says he'd totes baptize aliens if they landed on Earth:

Pope Francis would absolutely baptize an alien from Mars, if one showed up at the Vatican and asked for it. During his weekly homily on Monday, Franics said that aliens — which he imagines could be "Green, with that long nose and big ears, just like children paint them" — should be baptized just like anyone else who asks for it, because it's not up to any human to decide who should receive the Holy Spirit. In other words: if God prompts some Martians to come to Earth, find the Pope, and say "we want in on this Catholicism thing," the pope would probably say "OK. cool." But probably in Latin.

So, just for the record, the pope can totes imagine baptizing beings from another world, of whose existence there is no evidence, but cannot imagine why it might be a good idea to marry two people of the same sex or give women control over our reproduction. Neat!