Every other year, the Jesuit-run observatory holds a monthlong summer school dedicated to a different area of research in the astronomical sciences, examining everything from comets and meteorites to the nuclei of galaxies.
The students this year were chosen from 150 applicants from all over the world. The Vatican organizers make sure each group is as culturally and geographically diverse as possible, with an emphasis on accepting young people from developing nations, who receive scholarships covering 75 percent of traveling and living costs.
The students listen to daily lectures by visiting scholars and participate in evening seminars with the Vatican Observatory staff, who are all Jesuits and accomplished scientists.
The students also present papers on their own research or the research being done at their universities and engage in a variety of laboratory exercises.
Jesuit Brother Guy Consolmagno, curator of the Vatican's meteorite collection, which is one of the largest in the world, said that for many of the students, it's the first opportunity to make a public presentation of their work in English, hence "good practice" for their future careers.
He said the Jesuits want to give the young scholars a chance to meet expert researchers and discover what astronomers in other countries are doing.
Despite their vastly different backgrounds -- coming from countries that include Madagascar, Vietnam, Nepal, Armenia and Taiwan -- the students share a love for, and language about, the universe.
"Astronomy is probably the most universal science because the sky is the same for everyone," said Nikolay Kacharov, a 24-year-old Bulgarian Ph.D. candidate at the University of Heidelberg in Germany. He is studying the chemical composition of star clusters in the Milky Way.
"In the past, every culture in the world has worshipped the skies, now they study them" to ponder the same eternal questions of how the world came into being and how it is evolving, he said.
"We owe all the fancy things we own, like smartphones and computers, to the fundamental sciences and physics," which is what all future technological developments will depend on as well, Kacharov added.
According to Lori Beerman, 29, who studies star clusters in the Andromeda Galaxy at the University of Washington in Seattle, astronomy is important because "it's about knowing what is going on with the world; it's being curious and having this sense of discovery that I think is important for your spirit" as well as for society.
Pope Leo XIII formally established the Vatican Observatory in 1891 as a visible sign of the church's centuries-old support for science. At that time, Brother Consolmagno said, a myth was forming that somehow the church and science were opposed.
The observatory traces its origins back to the observational tower erected at the Vatican by Pope Gregory XIII in 1578 in preparation for reforming the Western calendar.
"The church has always supported science," he said. "You had to learn astronomy as one of the seven courses in medieval universities before you got to go on to theology or philosophy."
This was only logical, he says, because "if you believe that God created the universe, knowing how God created the universe is a way of getting to know God. And appreciating this creation is a way of letting God speak to us through creation because God does speak to us through the things that he made."
The first papal observatory was moved from the Tower of the Winds inside the Vatican walls to the papal summer residence in Castel Gandolfo in 1935. And then the Jesuit observatory staff set up a second research center in Tucson, Ariz., in 1981 after Italian skies got too bright for nighttime observation.
Both Beerman and Kacharov said they were curious to see priest-astronomers in action, having previously heard about the work of the Vatican Observatory.
"I always wondered how that worked," said Beerman. Seeing men merge their faith with their love for science "is not a problem for them, they're both astronomers and have the calling to be priests," she said.