You forget relativity. Time for the observer travelling at the speed of light appears slower when observing the objects that are NOT travelling at the speed of light, but time for that same observer would appear to be normal relative to the observer himself. Objects observing the traveller moving at the speed of light remains normal relative to themselves but time for the objects travelling at the speed of light would appear to run faster. Consider GPS satellites and the highly accurate clocks that ran normally here in atmosphere relative to everyone and everything travelling at the same speed. Once they went into orbit, these highly accurate clocks drifted ahead in time at a syncronized rate because they were travelling at high speeds above the Earth. Time is not a spacial dimension, per se. It is a dimension, it can be travelled faster and slower (as yet, you can only travel FORWARD) and it is effected by gravity, but you cannot describe it as spacial.