Can a person, in principle, travel from Earth to the galactic center (which is about 2.3e4 lightyears distant) in a normal lifetime? Explain, using either time-dilation or length contraction arguments. If they want to make the trip in 24 y what distance would the person travelling at nearly the speed of light measure (in light years)
To make the trip in 24 years, one way, the distance to the center would have to be shortened to 24 light years, in the spaceship's coordinate system. The relativistic contraction can accomplish this.
They'd better watch out when they get there. The center of the galaxy is a black hole. They'll probably burn up due to bombardment by relativistic interstellar dust and micrometeorites before they get there..