General Relativity as a Gauge Theory

[sidkeith]

Hello! Special Relativity seems intuitively quite clear as a way to preserve equality among observers -- in order for everyone to measure light as having the same speed, time has to slow down for some of them. This is a satisfying way to understand the theory. I've heard that General Relativity is the same -- a "gauge" theory that guarantees equality of observations among people experiencing different amounts of acceleration, but I've never understood how this operates. How does gravity work to overcome the differences induced by acceleration, in the same way as time dilation works to equalize moving but not accelerating observers in Special Relativity? Can anyone help me in understanding this? I feel that the farthest-ranging and most beautiful theory in history is passing me by! Thanks, Sidney Keith

[loglo]

Welcome to BAUT, Sidney!

The answer to this one is fairly simple. Gravity in GR is pictured as a warping of spacetime rather than a force. The greater the gravity, the deeper the "well", the slower time runs (from a distant observers perspective). So GR keeps space and time sorted out pretty much the same as in SR but adds non-inertial frames and some tricky 4-dimensional tensor maths to boot.