According to Swartzchild, what appeared when a star's mass was concentrated into a single point?

• A. A boundary
• B. A neutron star
• C. A white dwarf
• D. A supernova

Answer: (A)

Schwarzschild’s idea shows that if enough mass is squeezed into a region so that its radius is smaller than the Schwarzschild radius, a boundary forms around it—the event horizon. This boundary isn’t a physical surface you can touch; it’s a point in spacetime where nothing, not even light, can escape. So when a star’s mass is concentrated into a single point, the concept that appears is this boundary around a singularity, defining a black hole.

The other outcomes—a neutron star, a white dwarf, or a supernova—are different results of stellar evolution and collapse driven by pressure support or explosive processes, not the emergence of an event horizon.