There could be alien life forms and believing they exist isn't contradictory to having faith in God, the top astronomer at the Vatican said in an interview published Tuesday.
In the Vatican newspaper piece, titled "The Extraterrestrial Is My Brother," the Rev. Jose Gabriel Funes said the expansiveness of the universe means there could be life on planets other than Earth.
"In my opinion this possibility exists," Funes, the director of the Vatican Observatory, told L'Osservatore Romano. "Astronomers believe the universe is made up of 100 billion galaxies, each of which consists of 100 billion stars. ... Life forms could exist in theory even without oxygen or hydrogen."
Funes said that there might even be other intelligent life out there, but believing in its existence doesn't pose a problem for those of the Catholic faith.
"It is possible. So far we have no proof. But certainly in a universe so big we can not exclude this hypothesis," he told the paper.
"As there is a multiplicity of creatures on earth, so there may be other beings, intelligent, created by God. This does not conflict with our faith, because we cannot put limits on the creative freedom of God."
He said human beings could even consider another life form an "extraterrestrial brother" because it, too, would be one of God's creatures.
"How can we rule out that life may have developed elsewhere?" Funes said. "Just as we consider earthly creatures as 'a brother,' and 'sister,' why should we not talk about an 'extraterrestrial brother'? It would still be part of creation."
The interview covered a variety of topics, including the relationship between the Roman Catholic Church and science, and the theological implications of the existence of alien life.
Funes said science, especially astronomy, does not contradict religion, touching on a theme of Pope Benedict XVI, who has made exploring the relationship between faith and reason a key aspect of his papacy.
The Bible "is not a science book," Funes said, adding that he believes the Big Bang theory is the most "reasonable" explanation for the creation of the universe. The theory says the universe began billions of years ago in the explosion of a single, super-dense point that contained all matter.
But he said he continues to believe that "God is the creator of the universe and that we are not the result of chance."
Funes urged the church and the scientific community to leave behind divisions caused by Galileo's persecution 400 years ago, saying the incident has "caused wounds."
In 1633 the astronomer was tried as a heretic and forced to recant his theory that the Earth revolved around the sun. Church teaching at the time placed Earth at the center of the universe.
"The church has somehow recognized its mistakes," he said. "Maybe it could have done it better, but now it's time to heal those wounds and this can be done through calm dialogue and collaboration."
Pope John Paul declared in 1992 that the ruling against Galileo was an error resulting from "tragic mutual incomprehension."
The Vatican Observatory has been at the forefront of efforts to bridge the gap between religion and science. Its scientist-clerics have generated top-notch research and its meteorite collection is considered one of the world's best.
The observatory, founded by Pope Leo XIII in 1891, is based in Castel Gandolfo, a lakeside town in the hills outside Rome where the pope has a summer residence. It also conducts research at an observatory at the University of Arizona, in Tucson.
The Associated Press contributed to this report.