Unveiling the Cosmos: The Evidence Behind the Big Bang

Why does the universe have to expand? Was it ever wearing something? You probably guessed it; it’s not shedding its clothes, but rather expanding. This phenomenon, discovered about a generation ago, definitively disproved the ancient Greek philosopher Aristotle’s theory that the world has always existed. The universe is expanding, indicating it had a starting point. Today, we call it the ‘Big Bang,’ which in tradition is known as the moment of creation.

In 1913, a young astronomer at an observatory in Arizona decided to investigate a mysterious light spot in the sky. The man, Vesto Slipher, discovered that it was an unknown galaxy, which he named ‘Andromeda.’ Later that year, Slipher found that this new galaxy was moving away from Earth at more than a million kilometers per hour. Examining several galaxies near Andromeda revealed an even more astonishing finding: they were all rapidly distancing themselves from Earth.

Slipher dedicated his subsequent years to studying this puzzling phenomenon. By 1925, he had recorded no less than 42 different galaxies all moving away from us at high speeds. Slipher couldn’t find a logical explanation for this occurrence.

Meanwhile, in Germany, Albert Einstein developed his general theory of relativity. In 1916, the first copies of the theory were published. The scientific world was overwhelmingly impressed, but a Danish mathematician named Willem de Sitter noticed a problem. "Your theory," he wrote in a letter to Einstein in 1917, "will only work if we assume the universe is in a state of expansion where all its components are moving away from one another."

In 1922, Soviet mathematician Alexander Friedmann reached the exact same conclusion. If Einstein is correct, claimed Friedmann, then the universe should be expanding in all directions.

Due to the outbreak of World War I, neither de Sitter (in Denmark) nor Friedmann (in Russia) knew that young Vesto Slipher (in the USA) had already identified dozens of galaxies doing precisely this.

The war ended, and various scientists shared their discoveries with Einstein. However, Einstein was skeptical of the idea of an expanding universe, primarily for philosophical reasons. He even added an utterly unnecessary constant to his equations, his ‘cosmological constant,’ intended to negate the need for a universe in expansion. Einstein was aware of the theological implications of an expanding universe. In a letter to a friend, he wrote: "I still haven’t fallen into the hands of the clergy." In a letter to de Sitter, he wrote: "The idea of an expanding universe annoys me."

Nevertheless, the evidence continued to accumulate. In 1925, astronomer Edwin Hubble published the findings of a comprehensive survey he conducted of all galaxies up to a hundred million light-years from Earth. All of them, he reported, are moving away from us. In response, Einstein admitted that the cosmological constant he invented was the most significant scientific blunder of his life.

However, in 1965, a discovery decisively tipped the scales in favor of the Big Bang theory.

That year, two physicists, Arno Penzias and Robert Wilson, discovered cosmic background radiation. Years earlier, physicists had hypothesized that if the Big Bang theory was correct, then the massive radiation accompanying the universe’s creation should be detectable today at an electromagnetic frequency equivalent to a temperature 3 degrees above absolute zero. When radiation exactly at this frequency was discovered by Penzias and Wilson, it drove the final nail into the stable state model. The Big Bang revolution swept the entire scientific community.

The Russians, then a great and secular communist power, attempted to refute the discovery with various arguments, but the resistance couldn’t hold against the astronomical facts. In the end, everyone was convinced.

So yes, our world has a starting point. A significant step toward faith.