The dome of St Peter's Basilica is ideal for use as a planetarium
St Peter's Basilica could be used as a makeshift planetarium
The new Pope is considering letting astronomers use the dome of St Peter's Basilica in Vatican City as a makeshift planetarium, in a bold attempt to heal the long-standing rift between science and religion. Pope Francis has already given his blessing to the plan, which would see the constellations being projected onto the dome's interior as they would have appeared around the time of Jesus's death. The Pope's interest in the cosmos is said to have been sparked after he was shown recent images of the cosmic microwave background – dubbed the echo of the Big Bang – obtained by the European Space Agency's Planck mission.

The dome plan is believed to have been hatched by astronomers at the Vatican Observatory, which has its headquarters at the Pope's summer residence in Castel Gondolfo south-east of Rome. Like Pope Francis himself, all staff at the observatory are Jesuits and they also run a 1.8-m telescope in Arizona in the US. According to observatory insiders, the pontiff is keen to let Vatican astronomers into St Peter's after Sunday mass next Easter. Constellations would be beamed onto the inner walls of the dome using special LED projectors installed in the Blessed Sacrament chapel, which is said to be the most mystical in the entire basilica.
Completed in 1590, the dome of St Peter's is perfectly hemispherical and has an internal diameter of 41.5 m, which would make it easily the world's biggest planetarium. The Pope is keen to black out the dome's windows with VELUX blinds and has suggested temporarily covering its historic frescoes – inspired by Michelangelo – with altar tablecloths. The pontiff would sit on a cushioned stool in the gallery running round the inside of the dome, which would also have seating for a further 200 senior clerics. Members of the public would view live coverage of the event on TV screens in St Peter's Square.

Divine host

Astronomers are now looking for a suitable host for the event who will be able to translate complex scientific arguments into simple language. The front-runner is the Pope's official astronomer Brother Guy Consolmagno, who in 2010 told journalists at the British Science Festival that he would baptize an alien "but only if he were asked". Another option is Hollywood actor Morgan Freeman, who last Christmas apparently sent Pope Benedict XVI a DVD box set of his hit science TV show Through the Wormhole. Senior Church figures in Ireland, however, are said to prefer the comedian and broadcaster Dara O Briain, who studied physics at University College Dublin and recently co-presented the BBC's Stargazing LIVE with Brian Cox.
Born in Argentina – home to the Pierre Auger Cosmic Ray Observatory – Pope Francis is known to be keen to heal the centuries-long rift between the Catholic Church and the scientific community. Relations have steadily improved since Pope John Paul II's official 1992 apology for the trial of Galileo Galilei, and recent years have also seen a resurgence of the Pontifical Academy of Sciences, which boasts Stephen Hawking, former CERN boss Carlo Rubbia and string theorist Ed Witten as members. Vatican officials are even considering installing a small personal telescope in the Papal Apartment.

Symbolic effort

Father Cormac Lemaître, a relative of the Belgian priest Georges Lemaître, who in the 1920s obtained the first evidence that our universe is continually expanding, told Physics World that he was "delighted" at the pontiff's efforts. "This initiative symbolizes the simple pleasures of Pope Francis and illustrates his deep concern for the welfare of his fellow citizens," he says. Father Cormac adds that the Pope is believed to be considering brushing up on his physics by joining the now-retired Pope Benedicit XVI on a physics correspondence course. He is also encouraging both the current and former pontiffs to become IOPimembers of the Institute of Physics, which would give them a year's access to the digital version of Physics World magazine for just €20.