The question of what caused or created the Big Bang is still a subject of scientific investigation and philosophical speculation. The current understanding of the Big Bang is that it represents the earliest known moment in the history of the universe, approximately 13.8 billion years ago, when the universe rapidly expanded from a highly dense and hot state.
According to the prevailing scientific model, known as the standard cosmological model or the Lambda-CDM model, the universe was in a state of extreme density and temperature prior to the Big Bang, but our current understanding doesn't extend beyond that point. The laws of physics, as we currently understand them, break down near the singularity of the Big Bang, making it difficult to determine what happened before or at the instant of the Big Bang.
In terms of what caused the Big Bang, there are several hypotheses and theories that attempt to explain it, but they are highly speculative and have not been confirmed. Some cosmologists propose that the Big Bang could have been caused by a quantum fluctuation or a phase transition in a pre-existing universe or a multiverse. Others suggest that it might be a result of the collision between two branes in higher-dimensional space.
Ultimately, the question of what caused the Big Bang or what existed before it remains an open question in cosmology and physics. It's an area of active research, and scientists are continuously working to refine our understanding of the early universe. It's important to note that it's also possible that the concept of "cause and effect" may not be applicable or meaningful in the context of the origin of the universe, as our everyday notions of cause and effect may not apply to the fundamental nature of the cosmos.