What caused the Big Bang?

Twentieth-century cosmology delivered one of the biggest surprises in the history of science: the universe is not eternal. The observation that galaxies are moving away from each other, combined with the discovery of cosmic background radiation and the mathematics of general relativity, converged on a single picture, the universe, including space, time, and matter themselves, had an actual beginning roughly 13.8 billion years ago, often called the Big Bang. Even later theoretical work by cosmologists with no theological agenda concluded that any universe which has on average been expanding cannot be eternal in the past; it must have had a beginning.

This was, for many scientists at the time, an unwelcome discovery. An eternal universe conveniently sidestepped the question of a beginning, and by extension a Beginner; a universe with a genuine starting point reopened a question science had hoped to set aside for good. Some of the strongest early resistance to Big Bang cosmology came not from lack of evidence but from an evident discomfort with its theological implications.

This scientific consensus lines up strikingly with a very old philosophical argument, sometimes called the kalam cosmological argument: whatever begins to exist has a cause of its existence; the universe began to exist; therefore the universe has a cause. Each premise is defensible on its own grounds, nothing in ordinary experience or in careful philosophy suggests things can simply pop into being uncaused out of absolutely nothing, and modern cosmology increasingly confirms that the universe itself is not eternal but had a genuine starting point.

If the universe, all matter, energy, space, and time, had a beginning, then its cause cannot be one more physical, material thing, because physical things are themselves part of what needed causing. The cause must be beyond space, spaceless, beyond time, timeless or at least not bound by time as we experience it, beyond matter, immaterial, and enormously powerful, capable of bringing an entire universe into being. Because the universe's beginning is a specific event rather than an eternally existing, automatic effect, many philosophers argue the cause must also be personal, a mind capable of choosing to create at a particular moment, rather than an impersonal force that would produce its effect eternally if it existed eternally.

Long before modern cosmology, Genesis opened with exactly this claim: "In the beginning, God created the heavens and the earth" (Genesis 1:1), a definite beginning, not an eternal universe, caused by a personal, powerful, transcendent God. The psalmist celebrates this same truth: "By the word of the LORD the heavens were made, and by the breath of his mouth all their host" (Psalm 33:6). John extends the picture into the New Testament, identifying that creative Word with Christ himself: "In the beginning was the Word... all things were made through him, and without him was not any thing made that was made" (John 1:1-3).

Some propose that the universe emerged from an earlier multiverse, or that quantum fluctuations in a pre-existing field produced the Big Bang without need of a further cause. These proposals do not actually eliminate the need for a cause; they simply relocate the beginning to an earlier stage that itself requires explanation, a multiverse or a quantum field is still something, with its own structure and laws, not the philosophical nothing that would avoid the argument altogether. Pushing the question back a step does not answer it.

Philosophy and cosmology together can bring you to the edge of a striking conclusion: an enormously powerful, personal, timeless cause outside the universe. Scripture takes you the rest of the way, introducing you not to an abstract force but to the God who not only spoke the universe into being but also entered it in Christ, so that the same power that caused the Big Bang is the same love that went to the cross for you (Colossians 1:16-17).

That is, in the end, the most striking part of the Christian answer. Many worldviews are content to stop at an impersonal first cause, a force or a principle with no interest in what it produced. Scripture insists that the cause behind the Big Bang is not indifferent to the universe he made, and especially not indifferent to you, since the same God who said "let there be light" (Genesis 1:3) is the God who calls you by name.