Georges Lemâitre was a priest and astronomer who theorized Big Bang theory in the late 1920s, showing that universe had a point in time when it was created.

So yeah, the Big Bang is Christian.
Genesis 1:3, which states "And God said, 'Let there be light,' and there was light," and Isaiah 40:22, which says "It is he who sits above the circle of the earth, and its inhabitants are like grasshoppers; who stretches out the heavens like a curtain, and spreads them like a tent to live in," both speak of God creating light and the universe with the expansion of space.
The Big Bang theory is a scientific explanation for the origin of the universe, which suggests that the universe began as an extremely hot and dense state around 13.8 billion years ago. The
Cosmic Microwave Background (CMB) radiation is the residual heat left over from this expansion, which was discovered in 1964 by Arno Penzias and Robert Wilson.
Georges Lemâitre, a Belgian Catholic priest and scientist, is considered the father of the Big Bang theory. In the 1920s, along with Edwin Hubble, he proposed that the universe began as a singularity – an infinitesimally small and dense point of pure energy – that expanded and gave birth to the universe as we know it. Lemaitre's theory was influenced by his religious beliefs and his understanding of Einstein's theory of general relativity.
Isaiah 40:22 speaks of God stretching out the heavens like a curtain or tent, which can be seen as metaphorically related to the
expansion of the universe as described in the modern Big Bang theory. Additionally, Genesis 1:3 describes God creating light, which can be seen as a description of the creation of energy and matter in the Big Bang. The Cosmic Microwave Background radiation also supports these theories, as it provides evidence for the early expansion and cooling of the universe in the form of light, stretched into the microwave region of the EM spectrum.