TheoreticalCheckmate

Sound travels at 343.59 m/s , light travels at almost a million times that. So could we hear music at light speed?

It can't be detected but we see the effects of it. Could dark matter just be space? What if what we perceive as empty space is actually a space filled with dark matter and dark energy? After all , we really don't know what's outside the universe.

Let's say a man went to the future and killed his future self and then went back to the past (his present) , when that time in the future comes he would be killed by his past self (who had travelled to the future) , his past self (who travelled to the future) would then go back to the past and thus restarting the cycle , putting time for him in a never ending loop , he would practically be immortal. I call it the Rahemian Loop Paradox

Why does light , even on a dark night just seem to disappear ? Why doesn't it just continue on into space forever. Please explain.

Suppose we could build a car of photons , according to Einstein photons have no mass , therefore that car would be able to travel at the speed of light because it's practically built of light itself. But is it possible to build such a car and if it's how would one go about building it?