(For the record, I’m with Taylor – never a bad camp to be in.) It sounds inane, but the dress question was actually tricky: Some declared themselves firmly in the blue and black camp, only to have the dress appear white and gold when they looked back a few hours later.
Wired had the best explanation of the science behind the dress’s shifting colours.
This equation is based on two principles: “matter and energy make gravity…
somehow” and “when you don’t feel a push or pull in any direction, then you’re moving in a straight line”. The path of a freely falling object (even an orbiting object) is a straight line through a non-flat spacetime.
All we’ve really got are the experiments and observations, which led to a couple simple statements, which led to some nasty math, which led to some surprising predictions (including those concerning black holes), which so far have held up to all of the observations of known black holes that we can do (which is difficult because they’re dark, tiny, and the closest is around 8,000 light years away, which is Here’s the bad news.
It turns out that if that star gets smaller and keeps the same mass, that the shape of the space you’re in stays about the same (as long as you stay the same distance away, the density of an object isn’t relevant to its gravity).
Unfortunately no information ever escapes from beyond the event horizon.
So while we’ve got lots of tests that can check the nature of gravity outside of the horizon (the gravity here on Earth behaves in the same way that gravity well above the horizon behaves), we have no way to investigate the interior of the event horizon.
Instead of being emitted from some distant source, gravity is a property of the space you inhabit right now, right where you are.
This is the important point that the “bowling ball on a sheet” demonstration is The Einstein Field Equations describe the stretching of spacetime as being caused both by the presence of matter and also by the curvature of nearby spacetime.