ASTRO-110 Chapter Notes - Chapter 2: Escape Velocity, Flashlight, Gamma-Ray Burst
Document Summary
An object can escape the gravitational pull of a normal star or planet if it can travel faster than the escape velocity". Since nothing can travel faster the light, the event horizon is the surface of last escape for everything inside = trapped forever. General relativity: tells us space and time have to be treated as one, and gravity is what we see when objects try to follow the closest thing to a straight line through curved spacetime. When no forces act on an object it will travel on a straight line which is the shortest distance between two points when spacetime is flat (when curved the shortest path becomes curved) Gravity (curvature) tells matter how to move , and matter tells space time how to bend. When spacetime is empty and flat, circumference is 2(pi)r. When there"s a lot of mass, spacetime is curved and the distance from circle to center is larger so c<2(pi)r)
