how can universe be expanding faster than speed of light? general relativity doesn't apply here?
Idk, but if we travel 13B light years one way, it moves 13B the other then were at 26, and space itself has to have expanded 20 billion light years within the time it takes light to travel 13... So yeah, sounds like something is moving faster than light.
Let's try something much smaller and easier to reason about. Take a small fairly directional lamp (in my country we'd say a "torch" but words vary) and hold up a coin in front of it so that it makes a big obvious shadow on a far away wall, you may need to turn down ambient lighting. Relatively small movements of the coin result in the shadow moving quickly. Huh. How fast can that shadow move?
While the coin is a _thing_ the shadow is not, it's just your imagination processing the absence of light.
If you have a big enough room and a strong enough light source, you can do this trick so that a flick of the wrist appears to move the shadow much faster than the speed of sound. If a _thing_ did that in a room filled with breathable air you'd hear a sonic boom. But the shadow isn't a thing, it exists only in your imagination and so you hear nothing.
Large enough objects can occlude a star to have this effect on a cosmic scale. The shadow of a planet can pass over the face of another planet at faster than the speed of light. But no actual _thing_ moved, so no rules are broken by this happening, "faster than the speed of light" was only in your head, all the actual things (including the photons) obeyed the rules and stayed at or below the speed limit.