Atheism, by definition, is the lack of belief in any gods or deities. It does not necessarily entail a belief in an unknown creator or any alternative explanation for the origin of the universe. Atheists may have different views on the origins of the universe and the cause of the Big Bang, as atheism only pertains to the rejection of the belief in a divine being.
Regarding the question of how everything was made, including the cause of the Big Bang, there are various scientific theories and hypotheses that attempt to address these questions. The Big Bang theory, supported by substantial evidence, describes the expansion of the universe from a highly dense and hot state. However, it does not provide a definitive answer to what caused the Big Bang itself.
Scientists continue to explore different hypotheses and theories to better understand the origins of the universe. Some propose theories like inflationary cosmology or string theory, while others explore the possibilities of a multiverse or other concepts.
It's important to note that scientific explanations are based on empirical evidence, observations, and theoretical models, and they are subject to change and refinement as new information becomes available. The scientific process involves ongoing research, testing, and revision of ideas in order to better understand the natural world.
Ultimately, individuals, including atheists, may have their own perspectives on the origins of the universe, and these viewpoints can vary based on personal beliefs, scientific understanding, philosophical considerations, or a combination of factors.