The current understanding of cosmology, based on the prevailing Big Bang theory, suggests that galaxies as we know them did not exist before the Big Bang. According to the Big Bang theory, the universe originated from a singularity, a state of extremely high density and temperature, approximately 13.8 billion years ago.
The Big Bang theory describes the expansion of the universe from an incredibly hot and dense state to its current form. As the universe expanded and cooled down, matter began to clump together under the influence of gravity, eventually leading to the formation of galaxies, stars, and other cosmic structures.
Galaxies are vast collections of stars, gas, dust, and dark matter, held together by gravity. They are thought to have formed through the gravitational collapse of regions of higher density within the early universe. As the universe expanded, these denser regions continued to grow, eventually becoming the galaxies we observe today.
However, it's worth noting that the concept of "before" the Big Bang is not well-defined within the framework of current cosmological models. The Big Bang is considered the beginning of our universe as we understand it, and our current understanding does not extend beyond that point. Therefore, the question of whether galaxies existed before the Big Bang or if there were other forms of cosmic structures is not currently answerable with our current knowledge.