Here's why:
* Gravity vs. Pressure: The formation of stars is a delicate balance between gravity (pulling matter together) and internal pressure (pushing matter apart).
* Radiation Pressure: As a star's mass increases, its core temperature and nuclear fusion rate also increase. This leads to a massive output of radiation. This radiation exerts outward pressure, known as radiation pressure.
* The Limit: For stars exceeding a certain mass (roughly 100 times the mass of our Sun), the outward radiation pressure becomes so strong that it completely overcomes the inward force of gravity. This prevents the star from collapsing further and growing even larger.
In essence, the radiation pressure from a star's own nuclear fusion acts like a powerful outward wind, preventing the star from accumulating more mass and becoming too large.
