What is the initial structure where gravity causes slight density fluctuations to collapse, starting star formation?
Answer
Giant molecular cloud.
The genesis of every star begins within regions known as giant molecular clouds. These clouds are vast interstellar reservoirs composed predominantly of cold gas, mainly hydrogen, mixed with cosmic dust scattered across the galaxy. These areas act as the universe's stellar nurseries. Within these expansive, cold environments, minute variations in density allow gravity to slowly draw material together. As these clumps contract gravitationally, the conversion of gravitational potential energy into thermal energy causes the core to heat up, initiating the process that eventually leads to the formation of a protostar.
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