Albert Einstein and 100 Years of Relativity Christopher M. Johns-Krull Rice University, Dept. of Physics and Astronomy October 24, 2016

“Straight” Lines in Curved Spacetime If you are floating freely, then your worldline is following the straightest possible path through spacetime. If you feel weight, then you are not on the straightest possible path. He actually first tried an offset circle. 2

What is an Orbit? He actually first tried an offset circle.

A New Understanding of Gravity

An Orbit is a Straight Path Through Curved Spacetime He actually first tried an offset circle.

A New Understanding of Gravity

A New Understanding of Gravity

Precession of Mercury’s Orbit He actually first tried an offset circle. 8

Precession of Mercury’s Orbit He actually first tried an offset circle. GR Says time runs more slowly and space is more curved at perihelia 9

Now Gravity Can Affect Light

Now Gravity Can Affect Light If you are floating freely, then your worldline is following the straightest possible path through spacetime. If you feel weight, then you are not on the straightest possible path.

Newtonian Mechanics Hinted This

Gravitational Redshift

Gravitational Redshift: Measured in Lab

Deflection Depends on Mass

Gravitational Lenses

Gravitational Lenses

Gravitational Lenses!

Gravitational Time Dilation In the initial stationary frame, you & Jackie have watches flashing every 1 sec. Now let the ship accelerate. Your frames are constantly changing. Jackie’s flashes arrive at you more than 1 sec apart, while yours arrive at her less than 1 sec apart.

When the Charge Moves: Light! He actually first tried an offset circle. 20

Gravitational Waves! He actually first tried an offset circle. 21

Little Green Men? LGM-1

Pulsars

Pulsar Pulses Can’t explain with other things we know about because the period is too small

Pulsar Model

Binary Pulsars: Gravitational Waves? He actually first tried an offset circle. 26

Detecting Gravitational Waves He actually first tried an offset circle. 27

LIGO Results!

LIGO

LIGO Results!

LIGO Results!

Black Holes

Escape Velocity & Schwarzschild Radius

Event Horizon

Structure of a Non-Rotating BH