Drudge has linked to an article about the Vatican hosting a conference on astrobiology--the somewhat speculative field of science concerned with the possibility of extraterrestial life and, perhaps more significantly, the possibility that life arose on Earth as a result of being "seeded" by space rock. In the course of the AP article, a reference is made to Giordano Bruno who "was burned at the stake as a heretic in 1600 for speculating, among other ideas, that other worlds could be inhabited."
According to Wikipedia (I know, I know...but it's late at night, and I have homework to do...) the "other things" he was accused of include:
- Holding opinions contrary to the Catholic Faith and speaking against it and its ministers.
- Holding erroneous opinions about the Trinity, about Christ's divinity and Incarnation.
- Holding erroneous opinions about Christ.
- Holding erroneous opinions about Transubstantiation and Mass.
- Believing in metempsychosis and in the transmigration of the human soul into brutes.
- Dealing in magics and divination.
- Denying the Virginity of Mary.
Just sayin'.

It is underappreciated today that St. Thomas Aquinas (the theologian recognized by the Church since well before the 1600s as the most eminent expositor of Christian theology) was interested on philosophical and theological grounds in the question of the existence of extraterrestrial intelligent life.
For the record, he considered it improbable but not impossible.
The question, though not a threat to the Church, does have non-trivial philosophical and theological implications.
For an "artist's conception" of how ETs could conceivably relate to Christianity (though not the only possibility), I suggest C.S. Lewis' "space trilogy" Out of the Silent Planet and its sequels as a specially excellent example.
In lieu of the article in the Summa Theologiae which I don't have time to hunt down, here is an article that was published in The Thomist:
http://www.unav.es/cryf/extraterrestriallife.html#nota15
Posted by: Akh Ari | November 11, 2009 at 10:43 AM
I can't say that I'm the biggest fan of the Space Trilogy as far as its considerations on extraterrestrials go. I think That Hideous Strength, however, is the most poignant of the three books in terms of its social commentary.
Sometimes I feel as the the modern academy has already been taken over by N.I.C.E.
I think my favorite scene is of the professor (medievalist?) hopelessly fighting off N.I.C.E. agents with a tire iron.
I also think Lewis makes a really provocative case for why God doesn't bother giving us continual empirical evidence of his existence. In the novel, the scientists just turn their observations of supernatural entities into a theory of macrobes and completely miss the blindingly obvious spiritual implications of their discovery. Even if God did leave evidence for us, science would not be equipped to fully grasp what that evidence meant.
Posted by: Peter Terp | November 11, 2009 at 01:14 PM