Pope Francis discussed in a new interview topics ranging from his reasons for canonizing the parents of St. Therese of Lisieux, to his thoughts on whether there could be life on other planets.

The interview with French journalist Caroline Pigozzi of Paris Match was conducted in Italian, and published in both Italian and French Oct. 15.

Pigozzi is known for making the Pope's eyes light up in January when on board his flight to the Philippines she gifted him a silver bas-relief, or carving, of St. Therese of Lisieux, to whom he has a strong devotion.

In the interview, the Pope said that he is doing "well," but confessed that he is tired due to his recent Sept. 23-27 visit to the United States, as well as the demands of the current synod of bishops on the family.

He then responded to questions covering a wide variety of topics, including climate change, as well as his thoughts on whether or not extraterrestrials exist.

The journalist brought up NASA's discovery last July of a new planet, Kepler 452 B, which resembles Earth in its dimensions and characteristics, asking whether there could be thinking beings elsewhere in the universe.

"Honestly I wouldn't know how to answer," the Pope replied, explaining that while scientific knowledge has until now excluded the possibility of other thinking beings in the universe, "until America was discovered we thought it didn't exist, and instead it existed."

"But in every case I think that we should stick to what the scientists tell us, still aware that the Creator is infinitely greater than our knowledge."

Francis said that the one thing he is sure about in the universe and the world in which we live is that it "is not the result of chance or chaos," but rather of divine intelligence.

It is the result "of the love of God who loves us, who created us, who desired us and never leaves us alone," he said.

Pope Francis also spoke about the reasons behind his decision to canonize the parents of St. Therese of Lisieux, Louis and Zélie Martin. They will officially be declared saints by the Pope this Sunday, Oct. 18, and are the first married couple to be canonized together.

The Martins, he said, "are an evangelistic couple who throughout their whole life gave witness to the beauty of faith in Jesus, both inside and outside of their home."

At a time when "a certain bourgeois ethics" despised the poor with the excuse of maintaining a certain decorum, the Martins instead opened their hearts and doors to them, he said.

"Those two, with their five children, devoted their energy, time and money to help the needy. Certainly they are a model of holiness and of married life."

St. Therese, the youngest of the Martin's five children, is someone the Pope frequently goes to with special intentions, and to ask for favors.

He said that the reason for his strong devotion to the young Carmelite nun is that "she is one of the saints that speaks to us most about the grace of God."

"The little Therese understood in her existence what love is, the reconciling love of Jesus, which impels the children of his Church. This is what Therese of Lisieux has taught me," he said.

Francis said he also appreciates the saint's reflections on the dangers of gossip and "the spirit of curiosity," both of which he has spoken of often since his election as Bishop of Rome.

On the topic of climate change, the Pope was asked if he had a message for the upcoming climate summit in Paris. He responded by saying that "the Christian is a realist, not catastrophic."

"Because of this, we cannot hide the evidence: the current world system in unsustainable," he said, and expressed his hope that the summit "can contribute to a concrete choice, shared and farsighted, for the common good."

He said there must be an end to the "indiscriminate exploitation" of the planet and the deterioration of our common home, and that we must "protect man from auto-destruction."

To do this, humanity has to renounce the idolatry of money and again place the human being, their dignity and the common good at the center. Otherwise, "out descendants will be forced to live on heaps of rubble and dirt."

Pope Francis, who is a known pizza-lover, was also asked if he has ever considered hopping on a bus dressed as a simple priest and going to a Roman pizzeria.

In response, the Pope said that "I haven't completely abandoned my black clerics under the white cassock!"

"I would certainly like to be able to wander the streets still, the streets of Rome, which is a beautiful city." He said he has always been "a priest of the streets," and that some of Jesus' most important encounters happened there.

However, he also recognized that while he would love to go out and eat a good pizza with friends, it's not easy. In fact, he said that to do so is "almost impossible" for him.

Yet Francis did say that he has no lack of contact with people, and that as Pope he meets "many, much more than when I was in Buenos Aires, and this gives me great joy!"

"When I embrace the people I meet, I know that Jesus is keeping me in his arms," he said.

Francis also touched on his reasons for never visiting the U.S. until this year.   He explained   that the trips he made were all for meetings related to his duties either bishop or as master of novices, provincial and rector of philosophy and theology for the Jesuits, and that none of them were held in the U.S.

"None of those meetings, congresses or synods took place in the United States. This is the reason I never had the occasion to visit this country before."

Other topics addressed in the interview were migration, the refugee crisis, global conflicts and his reasons for calling the Jubilee of Mercy, which he said was the result of deep reflection and prayer.