Is it possible to reconcile the Big Bang theory of the beginnings of our Universe, and the Catholic
understanding of creation? It is indeed! In fact, when the Big Bang theory was first conceived,
it was met with skepticism, but not because it contradicted the Christian creation story,
but rather because it appeared to confirm it.
In the early 20th century, it was simply taken for granted by most scientists
that the Universe was infinite in time. But then, in the late 1920s,
a shocking new theory of the cosmos was proposed by the Catholic priest-physicist Lemaître:
beginning billions of years ago, the entirety of our universe had expanded out of something smaller
than the nucleus of an atom. Famous astrophysicist Fred Hoyle thought the idea so ridiculous
that he named it the Big Bang theory of the Universe’s beginning, and the name stuck.
Today it is generally acknowledged that the material reality, our universe, began with the
Big Bang, with the rapid expansion of the entire visible universe out of something smaller than an
atomic nucleus. But was this really a beginning? In one aspect it certainly was—we cannot access
what came before, and the Big Bang really is therefore the beginning of our material cosmos.
But the Big Bang does not describe something coming into existence out of nothing,
and should not be mistaken for creatio ex nihilo, creation out of nothing,
which is how God created the material and immaterial world.
Rather, the Big Bang describes the early development of a universe already in existence.
The Big Bang is then not proof of God’s creative act, but nor is it in competition with it.
While the Big bang is not proof for theological creation,
this does not mean that the existence of the Big Bang is theologically insignificant.
It seems strangely providential that just when atheism was taking over the academy,
we were gifted with the discovery that the whole visible universe has a single origin in time.
An icon, if there ever was one, of its Creation. The Big Bang does not prove creatio ex nihilo,
but it certainly makes it difficult to ignore that the universe might not have existed at all.
A temporally infinite universe,
the going scientific and philosophical theory in the nineteenth and early twentieth century,
also has no reason to exist without a cause. St. Thomas Aquinas realized that in the middle ages.
But somehow, discovering that the material universe had a beginning makes the question
“why something, rather than nothing exists” more present to us. This question could, and should,
lead the curious mind to ask: why then does the world exist? Who brought it into existence?
With that in mind, let’s return to the Big Bang, and how it unfolded. The earliest universe was
unimaginably dense and hot. But as the Universe began to expand it also began to cool down.
During the first fraction of a second of our universe, the density and temperature
decreased sufficiently for the different physical forces to separate into the ones we know today:
electromagnetism, gravity, and the weak and strong forces holding atoms together.
As the universe continued to expand, it cooled further. As it cooled, more and more complex
particles could stick together. Atomic particles, like protons, became stable within a couple of
minutes. During the following eighteen minutes, the conditions were just right for fusion, the
sticking together of atomic nuclei, and some of the protons and neutrons fused to form helium and
a little bit of lithium. There would be no other elements around for hundreds of millions of years.
400,000 years after the Big Bang, the universe had cooled down enough for atomic nuclei to keep
electrons captured and we have the first whole atoms (recall that an atom has two main parts:
a nucleus consisting of protons and neutrons, and a bound cloud of electrons).
Up until that point the light in the Universe was too energetic for atoms to exist. Light particles
or photons simply knocked off any electron that had managed to attach itself to a nucleus.
At recombination, this coming together of nuclei and electrons,
the light particles went below this energy threshold and as a result, light was released
from matter and began its independent existence. If you wish: light was separated from darkness.
Recombination also provided us with the universe’s first picture:
the cosmic microwave background radiation. This radiation field is the faint remnant of
the photons liberated when the universe was 400,000 years young. This cosmic microwave
background radiation was discovered by Arno Penzias and Robert Woodrow Wilson in 1964. This
discovery confirmed the Big Bang theory born in the mind of Fr. Lemaître three decades earlier.
A few hundred million years after the Big Bang, the universe first became cold enough
for some of the densest hydrogen and helium gas to collapse in on itself. The first stars were born
out of these implosions, and with them, a new cosmos emerged. The stars relit the universe,
leaving the previous dark ages behind (yes the Dark Ages is really what astronomers call it).
In the cores of the stars, hydrogen fused into heavier elements,
and when the stars started to explode into supernovae a few million years later,
they spread these new elements throughout the universe. Suddenly we have a universe
where there are building blocks for planets, for chemicals like water, and for organic life.
How does this scientific account of the origin and development of our universe
fit with creation as described within Christian tradition,
most famously in Genesis 1? In many ways modern cosmology is a good fit with the Christian story
with its emphasis on a beginning, and on creation unfolding in a series of steps.
Contrast this with the medieval Aristotelian cosmology which put the Earth at the center,
surrounded by unchangeable crystal spheres, or the cosmology of the early modern period,
which can be compared to a perfect clockwork that once wound up continues
to operate the same way forever. Both of these cosmologies were naturally static.
They had to have a beginning and a history imposed on them to fit with the Biblical narrative. Modern
cosmology has revealed that our universe, like the Bible’s description of creation, is essentially
historical and unfolds over time. This may help to explain the Catholic Church’s very warm welcome
of the Big Bang theory, and the special enthusiasm with which it was greeted by Pope Pius XII.
In light of this, it is interesting to return to the human origin of the Big Bang theory,
Fr. Lemaître, and to ask ourselves why was it a Catholic priest who first realized
the true nature of our cosmos? First of all, Lemaître possessed a perfect match
of scientific and mathematical understanding to comprehend Einstein’s novel relativity theory,
which provides the theoretical framework for the Big Bang theory.
Second, Fr. Lemaître was unusually well attuned to contemporary astrophysical discoveries, which were
starting to provide some hints for an expanding universe. These two facts could be sufficient when
combined with Fr. Lemaître’s own touch of creative genius to explain his remarkable discovery.
But I cannot help to think that his theological knowledge that the Universe had a beginning
in time had something to do with it. That it prepared him to take his scientific idea of the
Big Bang seriously when it arose in his mind. Vice versa, I think it is reasonable to speculate that
the materialistic atheism adopted by most of his contemporaries would have led them to consciously
or subconsciously prefer an eternal universe that did not raise the question of its origin.
This may very well have temporarily blinded them from pursuing similar theories themselves.
We will never know how long it would have taken for the theory of the Big Bang to come about
had it not been for the insight of Fr. Lemaître.
His scientific discovery is something that all Catholics can be proud of!