As we all know, the universe is expanding. Since the universe is space-time, it is space-time that is expanding, which to me implies that time must be expanding as well as space. That is the answer to what 'now' is: it is the leading edge of the expansion of the time component of space-time. The wave-front of NOW is instantiating the universe behind it as it expands from the past into the future.
Question: we know that gravity slows the expansion of space-time locally on the time axis, does gravity also slow the expansion of space-time locally on the 3 space axies?