Explainer: What to watch for when a new pope is chosen at the Vatican

By Anna Levy, ABC

The world's eyes are on the Vatican at the moment, as the new pope is soon to be decided through the secretive process of the conclave.

Soon, 252 cardinals from 90 countries will gather at the Vatican to discuss the major issues facing the Catholic Church. Then, the 135 cardinals who are eligible to vote will submit their ballots for the next pontiff.

A cardinal needs two-thirds of the vote to be elected as pope.

What happens next is dictated by centuries of tradition, but some previous popes - including the late Pope Francis - have put their own spin on the proceedings.

Here's what to expect when the conclave concludes.

How will we know a new pope has been chosen?

At the close of each voting session, smoke will billow out through the chimney of the Sistine Chapel.

If a pope has been elected, the smoke will be white. If not, it will be black.

There are two furnaces brought into the chapel for this purpose: one for burning the ballots as per tradition, and the other for generating additional smoke with chemicals to affect the colour.

Previously, this process relied on nature, with straw added to the ballots to create sooty black smoke to signal the cardinals had not yet reached an agreement.

But this caused confusion during the 1958 conclave - during which the straw failed to light and caused several false alarms - and the Vatican pivoted to using chemicals instead.

Using smoke as a signal dates back to ancient cultures, explains Clare Johnson, director of the ACU Centre for Liturgy, and professor of liturgical studies and sacramental theology.

"It's an obvious way for that [news] to be instantaneously communicated from within the Sistine Chapel itself," she said.

"Nobody can interfere with the smoke … so it's a universal way of communicating this very, very important decision."

In addition to the white smoke, the ringing of the bells of St Peter's Basilica serves as an audible confirmation that a new pope has been elected. Smoke and bells are the only ways permitted to communicate the news.

Crowds will likely be gathered at the Vatican throughout the conclave, as Catholics eagerly await the announcement.

In the 2013 conclave which elected Pope Francis, the decision was made in just over a day, making it one of the shortest conclaves in history. Some conclaves in the past have lasted years, but the rules have since been amended to speed up the process.

How does a pope choose his name?

After a cardinal has been elected, he will be asked by the dean of the College of Cardinals - in this conclave, Italian cardinal Giovanni Battista Re - if he is willing to accept his canonical election as the supreme pontiff.

If he answers in the affirmative, he will be asked by what name he would like to be known.

A new pope may choose his name for a number of "quirky and individual" reasons, Johnson said.

Pope Francis was the first of his name and chose it for Saint Francis of Assisi, a 13th-century Italian saint known for environmentalism, poverty and service to others.

"They can choose any name they wish, but in his case, it was somebody from whom he took great inspiration," Johnson said.

"It might be one of the apostles, it might be one of the other popes from history … but it will be very personal choice.

"You have to imagine that any of the 135 cardinal electors could be the next pope, and so they might all be thinking about it now."

The most popular papal name by far is John, with 21 popes of that name throughout history.

What's the Room of Tears?

Soon after he accepts his role and gives his papal name, the new pope will appear to greet Catholics around the world.

"People will be very hungry to get the news once that smoke has gone up," Johnson said.

The new pope will have a moment to himself in a small antechamber within the Sistine Chapel called the Room of Tears.

"The Room of Tears is aptly named as a place where they have a moment to themselves and can pray and prepare themselves for what's to come, and maybe think about what they want to say to the gathered crowds that will be waiting to hear those first words," Johnson said.

It can be a private moment of reflection for a new pope to "get used to the news that has just been thrust upon him".

"His whole life will change from that point," Johnson said.

What will the new pope wear?

Before appearing in public, the new pontiff will be adorned with formal papal vestments, though this is at his discretion. While Pope Benedict XVI donned traditional formal dress, wearing a red velvet cape and red shoes, Pope Francis opted for only his simple white cassock and zucchetto (skullcap) with black shoes.

A few days later, at his papal inauguration, he will be given the Fisherman's Ring, a signet ring stamped with an image of Saint Peter, who was a fisherman and is believed to be the first pope.

The ring, which has been part of papal regalia since the 13th century, is forged anew for each pope. It will be ceremonially destroyed upon his death or, as was the case for Benedict XVI, defaced to mark his resignation.

"[The ring] is a sign of apostolic succession, [showing] that from Saint Peter down to the current pope, we have a succession [of those] who are known by that title and have that ring," Johnson explains.

"It's one of the ways in which we know this is the leader of our church."

What will the pope say at his first appearance?

Once the pope is ready to make his first public appearance, the dean of the College of Cardinals will walk out onto the central balcony of Saint Peter's Basilica.

He will announce the Habemus papam - a Latin pronouncement which translates to: "I announce to you a great joy; we have a pope."

He will then reveal the name of the new pontiff.

The pope will greet the crowds from the balcony and give a traditional papal address in Latin, called Urbi et Orbi. This is the most solemn address in the Catholic Church and is only used at Christmas, Easter and upon the election of a new pope.

Typically, the pope will then greet different nations in their own languages.

However, Pope Francis broke the mould with his papal address in 2013. Instead of offering blessings, he asked the faithful to pray for him.

Commentators say this, combined with his humble dress, spoke to his plans to be "the people's pope" and to lead the Church with humility.

Whoever is elected as the new head of the Catholic Church, their first words to their followers may be similarly telling.

- ABC