* Gravity and Mass: The strength of a gravitational field is directly proportional to the mass of the object creating it. When a star collapses, its mass stays the same.
* Gravity and Distance: The strength of a gravitational field is inversely proportional to the square of the distance from the center of the object. When the star collapses to half its size, the distance from the center to the surface is halved.
Combining these factors:
* Increased Mass Concentration: Even though the mass remains the same, it's now concentrated in a smaller volume. This means the mass is closer to the surface, increasing the gravitational pull.
* Reduced Distance: Because the surface is now closer to the center, the gravitational force increases due to the inverse square law.
Therefore, the gravitational field at the surface of the collapsed star is significantly stronger.
This is a key factor in the formation of neutron stars and black holes, where the intense gravity compresses matter to incredibly high densities.
