how we can get enough vitamin d3 from the sun without putting our face skin in danger?
particular Relativity does no longer cope with acceleration via gravity, or something yet relatively ordinary, at once-line accelerations (and of course merely inertial action). accepted Relativity does, via way of the Equivalence theory.
It depends. Are you talking about visible light, infra red, UV, etc? All matter we know of reflects some light (there is no matter which is completely invisible). So it depends on specifically waht you mean. Hope this helps
Gravity is modeled as the curvature of spacetime, in General Relativity. This means that at any given point in space, there are more vectors that point at / towards a nearby mass, than away from it. This means that with each passing second, forward vectors are rotated towards the nearby mass. The rubber sheet analogy is not a good choice. A description cannot be made too simple, since we don't have the simple words to describe what the model says. All the simple words are tied up in describing the shape of members of the opposite sex and the creams they may smear on themselves, why other religions are wrong but not ours, in describing a world where the traffic jam under our feet keep us from following a force-free elliptical orbit about the common center of mass. In other words, you have to get free of words to see what the model says. That is what the formalism of the mathematics does for you provides a clear language that does not permit for misunderstanding.
