Black hole
### 10 Main Conditions of a Schwarzschild Black Hole 1\. Schwarzschild radius: 2\. Outside the event horizon: . 3\. At the event horizon: . 4\. Inside the event horizon: . 5\. Gravitational time dilation: for a stationary observer outside the horizon. 6\. Constant radial position: . 7\. Constant angular position: . 8\. Radial proper distance: on a constant-Schwarzschild-time slice. 9\. Light speed locally: remains constant for every local inertial observer in vacuum. 10\. Proper time at the horizon: A freely falling observer crosses the horizon in finite proper time; the apparent zero clock-rate factor applies to stationary Schwarzschild coordinates, not to the falling observer's own clock. Main conclusion: Gravitational time dilation increases as a stationary observer approaches the event horizon, but physical distance and time do not simply disappear.