Final answer:
Gas giants do not collapse into stars because they do not have enough mass to start nuclear fusion; instead, the pressure of gases within them balances out the gravitational forces.
Step-by-step explanation:
The gas giants in our solar system, such as Jupiter and Saturn, do not collapse into a star because they lack the sufficient mass to initiate nuclear fusion, which is the process that powers a star.
While the immense gravitational pull of a gas giant does work to concentrate its mass toward the center, creating high core temperatures, it does not reach the critical temperatures and pressures required for hydrogen atoms to fuse into helium, which is the crucial reaction that takes place in stars.
Instead, the gravitational forces are balanced by the pressure of gases, preventing collapse.