Many scientists now accept that the universe had a beginning and is therefore not eternal.  Because something cannot exist without a sufficient cause, whatever begins to exist has a cause that brings it into being, and since the universe began to exist, it is therefore not eternal but had a cause outside of itself.  Those who accepted the testimony of the Biblical book of Genesis had known for a thousand years before Aristotle that the universe had both a beginning and a beginner.  Uplook Magazine October 2007, p.4.  References:  F.A. Schaeffer, How Shall We Then Live? (Wheaton, IL: Crossway Books, 1969).  W.L. Craig,  God, Are You There? (Norcross, GA: Ravi Zacharias International Ministries, 1999).