How Old is the Universe?

In the beginning God created the heavens and the earth. (Genesis 1:1, NIV)
Then the LORD spoke to Job out of the storm. He said: “Who is this that obscures my plans with words without knowledge? ... Where were you when I laid the earth’s foundation? Tell me, if you understand.” (Job 38:1-4, NIV)

According to the dominant theoretical model of contemporary cosmology, which will be discussed later in this chapter, the universe exploded into existence approximately 13.8 billion years ago in an unfathomably powerful flash of light called the Big Bang. Understandably, this theoretical model is controversial among Christians who believe in the truth and authority of scripture. The Bible makes some specific claims about the beginning of the universe, and it is far from obvious how the scientific evidence fits with the biblical story. Has the Bible been refuted by science, as many people think? Or do the divinely-inspired words of scripture show that contemporary cosmology is dead wrong, as some Christians believe? If science contradicts scripture, those seem to be the only alternatives.

Most Christians believe, as I do, that the biblical creation story recorded in the first two chapters of Genesis isn’t merely a myth or fable, but describes something that really occurred. On the other hand, even among those of us who believe that the story is true, there is substantial disagreement about its precise meaning. For example, it is controversial whether the seven days described in Genesis were ordinary 24-hour days, or whether the description has a subtler meaning. Since the time of the early church, Christians have held a variety of different views concerning the story of creation. Some interpret the biblical creation story to mean that the universe came into existence just a few ordinary days (24-hour days) before the creation of the first man and woman. If that view is correct, then the universe is only a few thousand years old. As I will explain in chapter 10, however, there are numerous indications—within the Bible itself—that the “days” of creation do not refer to 24-hour periods.

Personally, I believe that the truth of the Bible is consistent with the idea that the universe was created billions of years ago. This may be an unpopular view, but I am not the only Christian who thinks the Big Bang is compatible with scripture. In fact, the Big Bang theory itself was first proposed by a Christian, a Catholic priest named Georges Lemaître. Moreover, during the first few centuries of the early church, some of the most thoughtful Christian leaders, apologists, and theologians—including Justin Martyr (AD 100 - 165), Irenaeus (AD 130 - 202), Clement of Alexandria (AD 150 - 215), Origen (AD 185 - 254), and Augustine (AD 354 - 430)—argued that the “days” described in the creation story represent something other than 24-hour days.

You may disagree, but please don’t write me off as someone who doesn’t take the Bible seriously. If you believe that the days of creation were ordinary 24-hour days, and that the universe is only a few thousand years old, I encourage you to read the first few sections of chapter 10 before finishing this chapter. In chapter 10, we’ll examine various ways of understanding the biblical creation account, and I will argue that some reasonable interpretations (including the one I think the author intended) are consistent with the evidence from astronomy and cosmology. Even if you aren’t persuaded that my understanding of scripture is correct, perhaps I can at least convince you that the “24-hour days” interpretation is not the only view that sincere, Bible-believing Christians may hold.

Throughout the remainder of this chapter, I will explain some widely accepted theories of astronomy and cosmology, including the Big Bang theory and the dominant models of how stars, planets, and galaxies formed. Regardless of whether you agree with them, you may find it helpful to know how astronomers and cosmologists arrived at their conclusions, and what evidence is taken to support these theories. In chapter 10, I will argue that these theories and models don’t contradict what the Bible says; they are compatible with the biblical account of creation. Given that they are consistent with the truth of scripture, I am happy to accept that the theories discussed in this chapter are at least approximately correct. But I’ll just present the evidence, and you’re welcome to draw your own conclusions.