Albert Einstein

Chronicled events

1. 1905​·​Einstein Splits Light into Quanta
   #5828

   Light’s energy comes in packets, quanta, each with an energy proportional to the light’s frequency, so bluer light has more energetic quanta. Each quantum is taken up whole, by one electron.

   #5829

   Lenard found that brighter light knocks more electrons out of a metal, but not faster ones. A spreading wave would shake the electrons harder the brighter it is, and send them out faster.

2. June 1911​·​Einstein Calculates How Much the Sun Bends Starlight
   #5756

   Gravity bends light. Starlight passing the edge of the Sun is bent by about 0.83 arcseconds.

3. November 18, 1915​·​Einstein Explains Mercury’s Orbit
   #5758

   My calculation of 1911 only counted how gravity slows time. It left out how gravity bends space, which bends light just as much again. So starlight passing the edge of the Sun is bent by about 1.7 arcseconds, not 0.83.

   #5759

   Gravity isn’t a force pulling across empty space. It’s the bending of space and time by matter and energy. Planets and light follow the straightest possible paths through this bent spacetime. Starlight passing the edge of the Sun is bent by about 1.7 arcseconds.

   #5761

   General relativity has to explain the extra movement of Mercury’s perihelion, which Newton’s law can’t.

   #5762

   General relativity explains it. It makes Mercury’s perihelion move 43 arcseconds per century more than Newton’s law does, with no hidden matter needed.