By Dan Merica, CNN

Washington (CNN) – She went from atheist to Catholic in just over 1,000 words.

Leah Libresco, who’d been a prominent atheist blogger for the religion website Patheos, announced on her blog this week that after years of debating many “smart Christians,” she has decided to become one herself, and that she has begun the process of converting to Catholicism.

Libresco, who had long blogged under the banner “Unequally Yoked: A geeky atheist picks fights with her Catholic boyfriend,” said that at the heart of her decision were questions of morality and how one finds a moral compass.

“I had one thing that I was most certain of, which is that morality is something we have a duty to,” Libresco told CNN in an interview this week, a small cross dangling from her neck. “And it is external from us. And when push came to shove, that is the belief I wouldn’t let go of. And that is something I can’t prove.”

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According to a Patheos post she wrote on Monday, entitled “This is my last post for the Patheos Atheist Portal,” she began to see parts of Christianity and Catholicism that fit her moral system. Though she now identifies as a Catholic, Libresco questions certain aspects of Catholicism, including the church’s positions on homosexuality, contraception and some aspects of religious liberty.

“There was one religion that seemed like the most promising way to reach back to that living Truth,” Libresco wrote about Catholicism in her conversion announcement post, which has been shared over 18,000 times on Facebook. “I asked my friend what he suggests we do now, and we prayed the night office of the Liturgy of the Hours together.”

At the end of the post, Libresco announces that she is in a Rite of Christian Initiation of Adults class and is preparing for baptism. She will continue to blog for Patheos, but under the banner, “A geeky convert picks fights in good faith.”

According to Dan Welch, director of marketing for Patheos, Libresco’s post has received around 150,000 page views so far.

“Leah's blog has gotten steadily more popular since she arrived at Patheos, but a typical post on her blog is probably closer to the range of 5,000 page views,” Welch wrote in an email. “Even now, a few days later, her blog is probably getting 20-30 times its normal traffic.”

Libresco’s announcement has left some atheists scratching their heads.

“I think atheists were surprised that she went with Catholicism, which seems like a very specific choice,” Hemant Mehta, an atheist blogger at Patheos, told CNN. “I have a hard time believing how someone could jump from I don’t believe in God to a very specific church and a very specific God.”

Mehta says that Libresco’s conversion is a “one-off thing” and not something that signals any trend in atheism. “The trends are very clear, the conversions from Catholicism to atheism are much more likely to happen than the other way around,” he said.

But while atheists were puzzled by the conversion, others commended Libresco.

“I know I’ve prayed for her conversion several times, always thinking she would make a great Catholic,” wrote Brandon Vogt, a Catholic blogger. “And with this news, it looks like that will happen. Today heaven is roaring with joy.”

Thomas L. McDonald, a Catholic Patheos blogger, welcomed Libresco to the fold: “Welcome. I know this was hard, and will continue to be so. Don’t worry if the Catholics make it as for difficult for you as the atheists. We only do it to people we love.”

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Libresco says one of the most common questions she has received is how she'll deal with atheists now.

“The great thing about a lot of the atheist and skeptic community is that people talk more critically about ideas and want to see proof provided,” Libresco said. “That kind of analytical thinking is completely useful and the Catholic Church doesn’t need to and should not be afraid of because if you’ve got the facts on your side, you hope they win.”

Libresco is just switching the side she thinks the facts are on.