Lecture 18 Flashcards
What is the main idea of general relativity?
-you cannot tell the difference between gravity and acceleration
-gravity depends only on the body generating the gravitational force
What is the equivalence principle?
Gravitational acceleration and acceleration due to a force produce the same effect
How does curved space effect geometry? (sphere)
-triangles have an internal angle of more than 180
-parallel lines can meet
-c<2pi*r
What curves spacetime?
Matter
What happens if the same amount of mass is condensed into a smaller radius?
Spacetime is curved to a greater extent.
What do Einstein’s Field Equations represent in simple terms?
‘geometry’=’mass’
What are some consequences of general relativity?
-time dilation due to gravity
-black holes
-gravity waves
How can we test for general relativity?
-GPS
-orbits
-gravitational lenses
How is time effected by the gravitational field?
Deeper in the gravitational field, clocks will run slower
What is a black hole?
A region of spacetime where gravity is so strong that light cannot escape it
How does Mercury’s orbit agree with general relativity?
The orbit does not exit in a perfect ellipse and Mercury precesses in a ‘flower’ sort of shape
What is gravitational lensing?
The gravitational field from a massive object causes light to be bent. This means that one object behind a massive object can appear as two
What are gravitational waves?
Ripples in spacetime caused by the motion of massive objects- the travel at the speed of light. As massive objects move, they change the shape of spacetime.
