what is time?
An Analogous Comparison:
--the clock is the tool(to a measuring tape), a second is the unit(to a centimeter), which measures an amount of time(to an amount of distance), which in reality is an amount of change(to an amount of space).
--change/and space, are both parts of reality, we perceive them as time/and distance, we measure them with units of seconds/and centimeters, with tools called clocks/and measuring tapes.
so like distance is our brains perception of space, time is our brains perception of change(the collective motion of fundamental particles that make up the universe), both equal but different methods of measuring reality. which our brains(biological computers) need to do so they can:
--process(measuring simplifies and quantifies reality down so our brain can process it) and:
--network(shared units of measurement act as a 'protocol', which allows communication of data between two brains)
--time travel is impossible, because it actually means change travel, which would be the ability to control the rate or direction of cause and effect in the entire universe.
Time Travel, practical applications:
--Travel to the future by freezing yourself which would slow time for you but by your perception in this slowed state speed time up for everything else hence give you the appearance of traveling into the future. Or take advantage of Einstein's theory of "motion time dilation" and travel to the future by accelerating to the speed of light, which would make all the atoms in motion including yours change less relative to those around them, therefore give the appearance of traveling into the future. Or take advantage of Hawking's theory on "alternate universes," travel to anytime by going into another universe whose atoms are in identical configuration to that of ours for the desired time period you want. Once again giving the appearance of having traveled to another time.