www.emc2-explained.infoPerhaps one of the strangest aspects of special relativity is that distances shrink in the direction of motion. This may not seem so important at first but it leads to something quite remarkable. Common sense tells us that if a spaceship travels at 90% of the speed of light then it would take about 11 years to reach a star 10 light years away, and that is indeed what a stationary observer would see and measure. However, for the spaceship not only time but distance will dilate and the star would be reached in about only 4.8 years. Going even faster reduces the time taken by an ever increasing amount
The journey time as viewed from Earth (years):
20
The journey time as viewed from the spaceship (years):
17.32050807568877