The Church recognizes that the spirit of biblical interpretation is not always literal.
Interpreting the Bible:
Science is not inconsistent with divine Creation, nor does the Church claim it is.
The big bang theory, which is now under some dispute with some scientists, dailymail.co.uk/sciencetech/article-2649885/Has-big-bang-breakthrough-foiled-DUST-Researchers-claim-major-flaw-discovery-found.html could be another way of saying God exploding the universe into existence. It isn’t contrary to God’s creation at all.
From the Catechism of the Catholic Church:
159"Methodical research in all branches of knowledge, provided it is carried out in a truly scientific manner and does not override moral laws, can never conflict with the faith, because the things of the world and the things the of the faith derive from the same God. The humble and persevering investigator of the secrets of nature is being led, as it were, by the hand of God in spite of himself, for it is God, the conserver of all things, who made them what they are"
From " Humani Generis" Encyclical by Pope Pius XII
36"the teaching authority of the Church does not forbid that, in conformity with the present state of human sciences and sacred theology, research and discussions . . . take place with regard to the doctrine of evolution, in as far as it inquires into the origin of the human body as coming from pre-existent and living matter—[but] the Catholic faith obliges us to hold that souls are immediately created by God"
Pope John Paul II, on the 23rd of October, 1996, while speaking to the Pontifical Academy of Sciences plenary session at the Vatican, declared the evolutionary theories of Charles Darwin to be fact, tacitly acknowledging that man evolved from the apes while teaching that at some period in history God gave souls to humankind, that leap from animal to human.
LORENZAGO DI CADORE, Italy - Pope Benedict XVI said the debate raging in some countries — particularly the United States and his native Germany — between creationism and evolution was an “absurdity,” saying that evolution can coexist with faith.
The pontiff, speaking as he was concluding his holiday in northern Italy, also said that while there is much scientific proof to support evolution, the theory could not exclude a role by God.
“They are presented as alternatives that exclude each other,” the pope said. “This clash is an absurdity because on one hand there is much scientific proof in favor of evolution, which appears as a reality that we must see and which enriches our understanding of life and being as such.”
He said evolution did not answer all the questions: “Above all it does not answer the great philosophical question, ‘Where does everything come from?’”
While evolutionary threads are banned, you do in fact have common ground for discussion with your atheist friend.