General relativity Solutions Moving Commentary

Albert Einstein physics

General relativity

• Einstein’s
• idea that
• spacetime is (as
• stated) curved by the
• energy or momentum of masses
• reconciles Newton’s law of universal gravitation—
• with its instantaneous attraction or action at
• a distance—with Einstein’s special relativity
• in which the speed of
• light is constant in
• all frames of
• reference.
• Let’s
• say
• mass
• or energy
• compresses or expands
• the framework of the
• universe and curvature means that
• the density of space
• increases and the
• density of
• time
• decreases.
• Nevertheless, the
• shape or density
• of spacetime affects the
• behavior of mass and energy—
• drawing planets to orbit the sun
• in ellipses warped by other planets, increasing
• the frequencies of electromagnetic waves, bending
• light around stars, and allowing
• massive objects to suck
• up everything around
• them, including
• light.

Solutions

• Einstein assumed that his field equations were unsolvable.
• Eventually, Schwarzschild found a solution for a spherical spacetime;
• Friedmann and Lemaítre found solutions for expanding and contracting universes;
• Reissner and Nordström found a solution for spherical objects;
• and Kerr and Newman found a solution for massive rotating objects.
• The theory was generally regarded as true
• when maybe only three people in the world understood it.

Moving

• Moving
• I deliberately set myself off balance.
• Moments
• I can tell simple things are misleading.
• Mondays
• all the rules have to be rewritten.
• Maybe
• even my wife doesn’t understand me.