Why did God make the universe so big? Why so much extra space if it’s just us? This is a question that both skeptics and believers have often asked, including myself. After all, why does there need to be a universe with some fifty billion trillion stars, which comprise merely one percent of the total mass?
Stephen Hawking raised this question years ago in his book A Brief History of Time. He suggested the vast size of our universe seems a waste. And Carl Sagan famously said, “The universe is a pretty big place. If it’s just us, seems like an awful waste of space.” Sagan suggested its size is good reason to believe there are other life forms in the universe.
Whether or not life exists in other parts of the universe, it turns out that the size of the universe is carefully calibrated and necessary for life’s existence on planet Earth. Astrophysicist Hugh Ross explains this phenomenon in his recent book Improbable Planet. He writes:
However, ongoing research has given us good reasons—all relevant to life’s existence—for the massiveness of the cosmos. We need it for essential construction materials.
The initial mass density of matter’s building blocks—protons and neutrons (called baryons. collectively)—critically impacted what happened the first few minutes of the universe’s existence. That’s when hydrogen, the lightest element, fused into the next heavier elements, helium and lithium. The amount of helium and lithium produced at the time then determined how much planet-and life-building material (the elements essential for life) could be produced later on within the nuclear furnace of stars.
If the universe contained a slightly lower mass density of protons and neutrons, then nuclear fusion in stellar furnaces would have yielded no elements as heavy as carbon or heavier; if a slightly greater mass density, then stars burning would have yielded only elements as heavy as iron or heavier. Either way, the universe would have lacked the elements most critical for our planet and its life—carbon, nitrogen, oxygen, phosphorous, and more. For life to be possible, the universe must be no more or less massive than it is.
Simply put, given the laws of physics in our universe, we need a universe as massive as it is for the construction of the materials that make life possible on our planet. If the universe were much smaller or bigger, we would not exist.
It turns out the universe is not full of wasted space. In fact, if the universe were not this massive, Stephen Hawking, Carl Sagan, and the rest of us could never even have been here to reflect upon it. Thank God we live in such a big universe.
Sean McDowell, Ph.D.is a professor of Christian Apologetics at Biola University, a best-selling author of over 18 books, an internationally recognized speaker, and a part-time high school teacher. Follow him on Twitter: @sean_mcdowell and his blog: seanmcdowell.org.
Resources for Greater Impact
 Hugh Ross, Improbable Planet (Grand Rapids, MI: Baker Books, 2016), 24.
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