General Relativity

Discussion

introduction

I will not define time, space, place and motion, as being well known to all.

Isaac Newton

Welcome to another paradigm shift.

principle of equivalence

Gravitational red shift.

ƒ = ƒ0
1 +  Vg
 = ƒ0
1 +  Gm
 ≈ ƒ0
1 +  gΔh
c2 rc2 c2

Gravitational time dilation

t = t0
1 −  2gΔh
−½
c2  

postulates …

  1. mass-energy curves space-time — a new version of Hooke's law
  2. objects trace out world lines that are geodesics (paths of least action in curved space-time) unless acted upon by a net external force — a new version of the law of inertia

Gravity isn't a force, it's the curvature of space-time caused by the presence of mass-energy

 Rμν −  1  R gμν  =  G  Tμν 
2 c4
space-time
curvature
 =  mass-energy
stress
     
strain  ∝  stress
ut tensio,  sic vis

or the presence of mass, energy, and (probably) an extra something-or-other

 Rμν −  1  R gμν  =  G  Tμν   Λ gμν 
2 c4
space-time
curvature
 =  mass-energy
stress
cosmological
constant

Matter tells space how to curve. Space tells mater how to move.

John Archibald Wheeler

Embedding diagrams.

Some predictions …