What Scripture says
The Bible’s first sentence is a claim about a beginning: “In the beginning, God created the heavens and the earth” (Genesis 1:1, ESV). Elsewhere:
- God is eternal, “from everlasting to everlasting” (Psalm 90:2), while the world is something he made.
- “All things were made through him, and without him was not any thing made that was made” (John 1:3).
- The world was created by God’s word, “so that what is seen was not made out of things that are visible” (Hebrews 11:3).
- Creation is not eternal; it “will wear out like a garment” (Psalm 102:25–26).
So Scripture teaches that the universe is not eternal. It had a start, and God was there before it. The Bible doesn’t say how long ago, or describe the physics.
What the evidence says
Science
For most of history, many thinkers assumed the universe was eternal. Aristotle did. In the early 20th century, so did Albert Einstein, who adjusted his equations to keep the universe static. Then the evidence changed.
Expansion
In 1929 Edwin Hubble showed that distant galaxies are moving away from us, and the farther away they are, the faster they recede. Space itself is expanding. Run the film backwards and everything converges into an extremely hot, dense state about 13.8 billion years ago. The Belgian physicist Georges Lemaître, a Catholic priest, first proposed this idea in 1927.
The afterglow
In 1965 Arno Penzias and Robert Wilson detected faint microwave radiation coming from every direction in the sky. It is the cooled afterglow of the hot early universe, the cosmic microwave background. Its temperature (about 2.7 degrees above absolute zero) and tiny ripples, mapped in detail by the COBE, WMAP and Planck satellites, match Big Bang predictions extremely well.
The right mix of elements
The Big Bang model predicts that the first few minutes produced about 75% hydrogen and 25% helium by mass, with traces of lithium. That is what astronomers observe in the oldest stars and gas clouds.
Running down
The second law of thermodynamics says usable energy steadily runs down. An infinitely old universe should already be in a uniform, dead state, with no stars left burning. Ours isn’t.
The BGV theorem
In 2003 Arvind Borde, Alan Guth and Alexander Vilenkin proved that any universe that has, on average, been expanding can’t be extended infinitely into the past. Vilenkin has written that cosmologists can no longer hide behind the possibility of a past-eternal universe. The theorem applies even to many multiverse models.
Philosophy
Philosophers add arguments that an infinite past is impossible in principle:
- You can’t cross an infinite. If the past were infinite, an infinite number of days would have had to pass before today. But you can never finish counting through an infinite series one day at a time. So today would never arrive.
- Absurdities of actual infinities. David Hilbert’s famous “hotel” with infinitely many rooms shows that actual infinities produce strange results: a full hotel can always take more guests. Some philosophers argue such things can exist only in mathematics, not in reality.
Others reply that infinities are strange but not contradictory, and that modern mathematics handles them fine. This part of the debate remains open.
Comparing the main proposals
| Model | Was there a beginning? | Status |
|---|---|---|
| Standard Big Bang | Yes, about 13.8 billion years ago | Strongly supported by evidence |
| Eternal inflation | The multiverse may be eternal; our universe began | Speculative; BGV theorem suggests a beginning anyway |
| Cyclic or bouncing universe | Endless cycles | Speculative; faces problems with entropy |
| No-boundary (Hartle–Hawking) | Time has no sharp edge | Speculative; still a finite past |
Where they meet
Genesis doesn’t give a physics lesson, but its central claim, that the universe had a beginning, is where modern cosmology has landed. That was not true a century ago. Some scientists initially resisted the Big Bang partly because it sounded too much like creation. The astronomer Fred Hoyle, who coined the name “Big Bang” as a dismissive label, preferred a “steady state” universe with no beginning. The evidence decided against him.
A beginning of the universe is exactly what the cosmological argument needs (see 1.1).
What’s still open
- The Big Bang marks the beginning of our expanding universe. Whether it was an absolute beginning of everything is still argued. Some models propose a prior phase, a cycling universe, or Hawking’s no-boundary idea, where time has no sharp edge.
- These proposals are speculative and have their own difficulties, but they are serious ideas from serious physicists, and Christians shouldn’t overstate the case.
- Science can describe the earliest moments; it can’t by itself say what, if anything, caused them. Physics breaks down at the very start, where a theory of quantum gravity would be needed.
Bottom line
Big Bang cosmology points strongly to a finite past, matching Genesis 1:1. The evidence includes the expanding universe, the cosmic microwave background, the mix of elements and the BGV theorem. It is rated Debated because whether that finite past was an absolute beginning is still an open question in physics.