WASHINGTON — NASA’s telescope Spitzer has discovered the largest batch to date of Earth-size planets around a star called TRAPPIST-1 — Transiting Planets and Planetesimals Small Telescope — providing new opportunities for examining the possibility of life on other planets.
The star and its planets are named partly after the famous beer brewed by Catholic monks and most enjoyed by the team of Belgian researchers who originally discovered the star.
NASA announced Feb. 22 the discovery of “the first known system of seven Earth-size planets around a single star.” While TRAPPIST-1 was known to have two planets back in 2015, the total size of the system was unknown until now. Three of these “exoplanets,” the scientific term for planets outside the solar system, orbit their star inside a habitable zone, in which it’s possible for liquid water to exist on their surface.
“Answering the question ‘Are we alone?’ is a top science priority, and finding so many planets like these for the first time in the habitable zone is a remarkable step forward toward that goal,” said Thomas Zurbuchen, associate administrator of NASA’s Science Mission Directorate in Washington, in a statement.
The search for extraterrestrial life has been an animating interest in the scientific community for decades, from early scientists like Nikola Tesla proposing a wireless means to reach Martians to a recent $100-million investment from Stephen Hawking and other backers to search for extraterrestrial life.
At the same time, theologians have engaged with the implications of Christian belief regarding the existence of aliens. While the potential existence of intelligent alien life does not hold the same urgency as it does in the scientific community, theology has a long tradition in its own right of speculation on extraterrestrials.
Seven Brave New Worlds
The TRAPPIST-1 system differs in significant ways from Earth’s solar system. The star is an ultracool dwarf about 40 light years away, and its farthest planet is closer to it than Mercury is to the sun. The closest planet takes 1.5 days to orbit around TRAPPIST-1.
Jesuit Brother Guy Consolmagno, the director of the Vatican Observatory, which operates a telescope in Arizona, told the Register that the discovery was important because scientists had “never found a system that had so many rocky planets that are still in a region where life might be stable.”
“These are bodies that are similar to earth, and we know that Earth supports life,” he said. “We’re just beginning to look [at the question]: Where can life be found? You start by looking at a place that looks like a place where we know life already exists.”
However, Hugh Ross, an astronomer and founder of Reasons to Believe, a Christian organization that shows how scientific research supports faith, raised some problems with the new system that NASA’s announcement may have overlooked.
“It’s hard to find planets that are any less habitable that the ones they’re talking about,” he told the Register.
Both he and Brother Consolmagno said that the planets would receive high amounts of radiation from their star and that they were likely to be tidally locked, like the moon is to Earth. One side of the planet would always be turned toward the star, making it hot, while the dark side would be significantly colder.
NASA, explained Ross, is also “looking only at one criterion for habitability,” whether or not a planet orbits its star at a distance that would allow liquid water to exist on a planet.
A planet that could host life like Earth “must simultaneously reside in nine habitable zones,” he said, and none of these planets do, adding, “In fact, none of them reside in even two, let alone all nine.” Other habitable zones concern orbits that receive the right amounts of ultraviolet radiation, the strength that tidal forces exert on a planet, and electric fields in the ionosphere.
“They’ve found 3,600 planets outside our solar system, but there’s still only one planet that simultaneously resides in all nine habitable zones.”
The search for life on other planets, however, can bring more appreciation for Earth’s uniqueness.
“You wouldn’t realize what a special and wonderful place this is, without seeing other places,” Brother Consolmagno told the Register.
Ross pointed out that uniqueness has led some scientists to be overly optimistic about life on other planets. “The origin of life happened here on Earth as early as the physics would permit, and it happened immediately,” which led some to conclude that this pattern would be duplicated elsewhere, he said.
But that view, he said, “overlooks [the fact] that unless life arose when it did, it would not have happened at all — we wouldn’t exist unless life had happened when it did.”
“This simply demonstrates once again how unusual our planets are,” said Ross. “We’re finding thousands of planets outside of our solar system, but we’re seeing nothing like the planets in our solar system.”
Pope Francis has previously mentioned extraterrestrials in the context of Christianity. In a homily at Casa Santa Marta, the Pope asked: “If, for example, tomorrow an expedition of Martians came, and some of them came to us ... and one says, ‘But I want to be baptized!’ what would happen?"
Brother Consolmagno, who wrote Would You Baptize an Extraterrestrial?, has said that he would, if he were asked to.
Robert Fastiggi, a professor of systematic theology at Sacred Heart Major Seminary in Detroit, told the Register that Canon 864 of the Code of Canon Law currently restricts baptism to human beings. If adult extraterrestrials were baptized, “it would be to incorporate them into Christ and the Church and to forgive any prior sins.”
“Ultimately, it would depend upon the magisterium of the Church to decide this matter, but I would urge caution,” he said.
Redeeming All of Creation
Baptism would come more easily than working through the Christological questions that would come afterward.
Michael Crowe, the Rev. John J. Cavanaugh Professor Emeritus in Humanities at the University of Notre Dame, said that while “there are no theological issues about pond scum,” the existence of extraterrestrial intelligent life “makes problems for incarnation and redemption. Is Jesus going to planet after planet, incarnating and dying on the cross to redeem the people of that planet?”
“There’s some real tensions with two fundamental Christian doctrines, incarnation and redemption, and belief in extraterrestrial intelligent life,” Crowe told the Register. “I’m not saying that proves there are no extraterrestrials; that would be silly. But there’s a tension there.”
Fastiggi told the Register that “if [extraterrestrial life] has true intelligence and rationality, then they’re in his image and likeness in some way. They would be directed to him and have some relationship to Christ.”
“He wouldn’t have to become incarnate again and again. There could be one Incarnation, but he would reveal himself to them in his own way,” he said.
Randall Smith, the Scanlan Professor of Theology at the University of St. Thomas in Houston, said, “I don’t think there’s any reason to affirm or doubt [intelligent extraterrestrial life] right now; we don’t have any evidence at the moment.”
But, he said, there is a tradition in the Church that says Christ’s work was for all creation, not just humanity.
“One would say from a Christian point of view that, with Genesis and the prologue to the Gospel of John, the God who creates is the God who redeems, and he redeems all of creation,” said Smith. “That would be the understanding, it seems to me, that we would have to take to our reflection on life in other worlds.”
Register correspondent Nicholas W. Smith writes from Rochester, New York.