The question was ignorant, as two minutes of Googling would show. However, to respond in such a brusque way without offering an explanation is just lazy and rude:
The Pope's proclamations are only considered infallible when speaking "ex cathedra", in other words from the Chair of St. Peter, in his role as the apostolic leader of the whole Church, in communion and in agreement with the bishops of the world, on matters of faith and morals.
Papal infallibility as described here has been invoked exactly twice in all of Church history, in both cases to officially declare doctrine that had already been universally agreed and believed by Catholics for centuries: The Doctrine of the Immaculate Conception, and the Doctrine of the Assumption of Mary.
Other than in his official capacity as the Vicar of Christ, the Pope's pronouncements are no more "infallible" than anyone else's, although one should expect that when he's talking about Catholic Doctrine, he would (or at least should) know what he's talking about.
This declaration is not news to anyone who knows anything about Catholic teaching. Pope John-Paul II said much the same thing, and the idea of evolution of life was hypothesized as far back as St. Augustine (and probably earlier... I bet the Greeks considered it). The nature of a logical and objective universe being the creation of God has always been consistent with Catholic teaching. Just read Thomas Aquinas. However, given how poorly Catholic teaching is understood, even among Catholics, and how much the Bible literalists and other fundamentalists have distorted the "common wisdom" of what Christians actually believe (especially in the U.S.), it is useful for His Holiness to point this out.