What temperature range characterizes the environment within cold cores of Giant Molecular Clouds?
Typically below 100 Kelvin
The initial stages of star formation require extremely cold conditions to allow gravity to effectively overcome the internal thermal pressure of the gas. The text specifies that observations of Giant Molecular Clouds reveal gas temperatures that are typically very low, settling below 100 Kelvin. This extreme coldness is essential because it minimizes the internal kinetic energy of the gas particles, thereby reducing the pressure that works against gravitational contraction. When combined with sufficiently high density (often $10^4$ to $10^6$ times the average interstellar medium density), these frigid temperatures allow the cloud material to collapse toward concentrations that satisfy the Jeans Mass requirement, leading to the formation of dense cores.
