Consider a space sip leaving Eath, accellerating over a two hour period to near lightspee, flying at lightspeed through, say, 5 million miles, then deceleratoing to a stop over a two hour period.
What is the experience of a passenger aboard that space ship. Would he percieve time and his own aging, to have advanced through less than 4 hours? I assume that the time spent at near lightwpeed would seem to pass in minutes.