The Secret Museum. Molly Oldfield

      BROTHER GUY CONSOLMAGNO IS THE curator of the Vatican Observatory. The observatory used to be in Rome, but moved out to the Pope’s summer home, Castel Gandolfo, in Albano, just outside Rome, when light pollution in the city made it impossible to see the stars.

      I took a train from Rome to Albano. When I arrived, Brother Guy was waiting on the platform. I had thought he might be in monk’s robes, but he was wearing a red waterproof jacket, jeans and trainers. That is because he is a Jesuit and his order don’t wear robes, they prefer to blend in and work among lay people. He was immediately friendly, bright and charming and I knew it would be a fun day.

      We walked up through the sleepy town until we reached the main square. It was quiet but for the sounds of birds and a few people chatting in restaurants. On one side of the square is a pink wall which divides the town from the papal grounds. Built into this wall is a door with a sign beside it carved into stone that reads ‘Specola Vaticana’. We opened the door and entered the Papal Grounds and the observatory’s museum. Guy explained that the Pope’s house is 2 kilometres away from the museum, across orchards and fields.

      The observatory isn’t often open to the public. More often than not, the curators and astronomers have the place to themselves. However, the day I visited they were preparing for the arrival of 500 diplomats from around the world the following week and there were several people painting walls and polishing clocks in anticipation.

      Guy showed me a film he was putting together for their visit. It tells the history of the observatory, one of the oldest astronomical institutions in the world. It was founded in 1582 when the Church replaced the Roman, or Julian, calendar with the Gregorian (which introduced the idea of having a leap year every four years to eliminate the discrepancies in time that had built up over the centuries). At first, the observatory’s telescopes pointed out at the universe from inside the Vatican itself, from a room called the Tower of the Winds.

      The telescopes were brought to Albano in 1935. Guy has worked here for years. ‘It’s much better out here, the security isn’t so tight,’ he jokes. He spends half of his year here, researching, writing and teaching astronomy students. The other half of the year Guy spends in the desert, at the second Vatican Observatory in Tucson, Arizona. This is the home of the Vatican Advanced Technology Telescope, a very high-spec model with an internal mirror designed by a man called Roger Angel. ‘Yes, the Pope’s telescope was designed by an Angel,’ said Guy. ‘It is used for exploring new areas of the universe. I use it for looking at the colours of faint comet-like objects out beyond Neptune. These are the things that Pluto was part of before we realized that Pluto is not a planet but part of the vast band of Trans-Neptunian objects.’ He works there with a team of 14 others.

      Back in Albano, Brother Guy works with another team to look after the observatory. He ushered me into the vast library of 20,000 books and journals. His favourite book is by a fellow Jesuit brother, Father Angelo Secchi (1818–78) and is called Sistema Solare, written in 1859. ‘It is the first book I’ve found that talks about the planets as real places you could walk around and have adventures on. Secchi takes facts and then uses his imagination to bring it all together. This book started planetary science. Before then, astronomers were far more interested in stars. Suddenly the planets became “places” rather than dots in the sky. They became things, not light.’

      Guy showed me the Mars chapter of the book and pointed out where Secchi describes Mars as having canali (Italian for ‘channels’) on its surface. Some people thought, incorrectly, that Secchi was describing canals, like the ones on Earth, which did much to encourage the idea that there was life on Mars.

      Outside the library is Brother Guy’s domain: the museum and its collection of space-related artefacts. There are different meteorites that flew around in space for around 15 million years until landing on our planet. Brother Guy explained that ‘10,000 pieces of rock fall to the Earth each year, but we humans collect about five of them, if we’re lucky. Most land in the ocean, or are lost because they look like ordinary rocks.’

      There are also three pieces of Mars. Each piece of Mars rock is from a different part of the planet. How do we know they are from Mars? Firstly, because other meteorites contain metals and Mars rocks do not. Secondly, they are a billion years old, which is young, compared to the 4,568 billion-year ages of the other meteorites. And, thirdly, bubbles of gas trapped inside them have been tested using a mass spectrometer, and it turns out that they exactly match the atmosphere of Mars, as recorded by the Mars Rover.

      The Vatican also has a globe of Mars, showing the channels on the planet, and a globe of the moon, the first ever made by NASA, given to the Vatican as a gift.

      I asked Brother Guy if he had a favourite treasure in the collection. He said that it changed all the time; he loves the Mars rocks, but his favourite meteorite that day was Allende. There are two tons of it in the world and it revolutionized science. ‘It fell in 1969, just before the moon landing. NASA had been buying all sorts of toys with which to measure moon rocks, which they hoped the astronauts would bring back to Earth. So they were able to test their toys on Allende. They discovered that the little white bits inside the meteorite were dust from stars that existed even before the planets were formed. This changed the way NASA thought about the solar system; they had known it was about 4.6 billion years old but, thanks to Allende, they could measure the age more precisely, to 4.568 billion’.

      Brother Guy got even more cosmic. ‘It’s strange to think that we humans – who are all made of stardust – look up at the sky to study galaxies, without often reflecting on the fact that what we’re actually studying is light. The things we’re looking at are no longer really there.’ That is one reason why he likes working in the meteorite lab, among the ‘real stuff’, which he can pick up and measure.

      We decided to visit his lab, but to have a drink first. Over a delicious coffee, which Brother Guy served in ‘Specola Vaticana’ cups, he told me how he had ended up as curator of meteorites at the Vatican. He grew up in Detroit. He loved space and saved up 16 books of stamps to swap for his first telescope. He joined the Jesuit order and it was they who decided that this was the job for him. He says he would have been just as happy serving soup, if that is what the Jesuits had decided, but he is surely the perfect man for the job here at the Vatican.

      Inside his lab, one surface is covered with microscopes and one weird instrument that looks like a saucepan, used to suck water off meteorites. The rest of the room is full of cupboards filled with drawers containing slices