(February 17, 2018 at 4:31 pm)shadow Wrote: From the article:
Quote: According to his theory of general relativity, gravity warps spacetime itself, which bends the path of massless photons.
Obviously I'm not a physicist, but I can't wrap my head around this. I don't know what they mean by spacetine or how gravity could affect something without mass. So the rest of the experiment doesn't make sense to meDoes anyone know of any good resources to understand the concept of general relativity?
Well, spacetime is exactly what it sounds like: space plus time. In other words, all space and all time.
Any mass (or energy, actually) will cause a curvature of spacetime locally according to Einstein's equations. This change in spacetime, in turn, affects the movement of matter and energy. It's a type of feedback loop.
In this experiment, the mass of the sun causes a distortion of space and time close to the sun which causes light going past to move away from the straight line path.
Now, for even something of the mass of the sun, this is a very small effect: the shift of 1.7 second of arc is equivalent to the size of a dime as seen from around 1 1/4 miles away.
More remarkably, the Newtonian prediction is half that amount. So they needed to determine the position of a star in the sky precisely enough to tell whether it was off by the size of a dime at 2 1/2 miles away.
if you want to understand GR better, it is best to first understand special relativity (where the concept of spacetime is investigated) and be prepared for some mind stretching stuff.
