Exam 2

michelson-morely experiement

an attempt to measure the motion of the Earth relative to the luminiferous aether

What was the result of the speed of the two lights from the michelson-morley experiment?

both lights moved at the exact same speed, and there was no ‘aether’ acting upon them

aether

an invisible material that wasen’t interacting with anything but was giving light it’s speed

originally, scientists thought that before the michelson-morely experiment light acted like

a wave, and a wave needed some material to travel through

luminiferous aether

the medium that light travels through that is too fast to observe, it is assumed it exists

interferometry

using interference to make a measurement of light

interferometry was used in

the michelson-morely experiment

the michelson-morley experiment was originally perceived as

a faliure

findings from the michelson-morley experiement

the speed of light is the same for ALL observers (no matter the motion) and the speed of light is a constant

the speed of light is a

constant

motion or relative motion the speed of light is

still the same for all observers

galilean relativity

the laws of motion are the same in all inertial frames of reference

what is this

galilean relativity

why does the michelson-morley experiment disprove galilean theory?

the Michelson-Morely experiment demonstrated that the speed of light is the SAME for ALL inertial observers

Einstein’s first postulate

The laws of physics are the same in all inertial frames.

Einstein’s second postulate

The speed of light is the same in all inertial frames.

most of our experiences cause us to believe that we live in a

combination of three dimensional space PLUS a one dimensional time

meaning of three dimensional

three numbers, coordinates, to completely describe the position of an event in space

space and time don’t depend on one another and are

independent of each other

inertial frame

no acceleration; remains stationary or moves at a constant velocity

non-inerial frame

moves in a non uniform or accelerated motion; newton’s laws of motion do not apply here

fictitious forces

forces that are '“invented” to account for accelerations in the accelerating frame

examples of fictitious forces

the coriolis effect, hurricane paths, hurricane rotations

the coriolis effect

in the three special dimensions, we can move

freely

examples of free movement in the 3 dimensions

forward/backward, left/right, up/down

however in the time dimension, we can

only move forward

the rate we move in time is fixed at

one second per second

nothing physical can depend on coordinates to

describe events

the distances between events are invariant and do not depend on

coordinates

the time between events is not invariant and does not depend on

which calendar we use

imagine we are

relativity of simultaneity

two events which are simultaneous in one inertial frame are not necessarily simultaneous in another inertial frame

Newton’s Laws don’t work in

non-inertial frames

1919 Eclipse

In 1919 there would be a total solar eclipse which would be able to demonstrate Einstein’s theory of curved light in space-time.

Einstein’s Theory of General Relativity is radical because it proposes that

gravity is unlike other forces

First Qualitative Rule from General Relativity

mass tells space-time how to curve

Second Qualitive rule from General Relativity

space-time tells mass how to move

Following the two qualitative rules of General Relativity, gravitational forces are not real and rather

all free-falling bodies follow straight paths in a curved space-time

anything whose apparently curved path is determined by gravity all are

following straight lines in curved space-time

?

Mass is curving space-time around it

Black Hole (BH)

an extreme curvature of space-time

Objects (light and matter) follow geodesics through

follow geodesics when in free-fall

A Black Hole’s spacetime curvature is so extreme that all geodesics

lead inward towards the center

The Schwarzschild Radius is the same as

The Event Horizon: The Point of No Return

?

The Schwarzschild Radius formula

The Schwarzschild Radius formula calculates for

The Event Horizon of a Black Hole

Geodesics

straight lines that move through a curved space-time

the shortest distance between two points follow

geodesics

Time Dilation

Moving clocks tick slower than stationary clocks

?

The Lorentz Factor

The heart of General Relativity lies with the

equivalence principle

in inertial motion there is no gravitational force that deflects

objects from their straight paths

General Relativity

gravity corresponds to changes to space and time, changing the straight paths objects naturally follow

takes three numbers, coordinates, to completely describe the position of an

event in space

Special Relativity

The laws of physics are invariant (identical) in all inertial frames of reference/The speed of light in vacuum is the same for all observers

(moving coordinates) The laws of motion are unchanged in

different coordinate systems

(moving coordinates) The laws of motion are unchanged

in different inertial frames