If time slows down the closer you get to the speed of light, does it follow that time does not exist for photons. Do photons - even if they travel across billions of light years of space - arrive at the same time as they are created? And if this is so, does this not explain the peculiarities of the double-slit experiment?
Time does not exist for photons. Quoting Wikipedia's somewhat unnecessarily technical page:
In relativity, proper time along a timelike world line is defined as the time as measured by a clock following that line.
The proper time between any two points along any photon's path in empty space is zero. So the photon "experiences" no passage of time.
It's not very clear to me how this could explain the double-slit experiment. Proper Time is an entirely relativistic concept, whereas the double slit results are not explained by relativity, but are explained by Quantum Mechanics.