The distance from earth to the center of our galaxy is about 30,000 light years (1 ly = 1 light year = 9.47 x 10^15 m), as measured by an earth-based observer. A spaceship is to make this journey at a speed of 0.9990c. According to a clock on board the spaceship, how long will it take to make the trip? Express your answer in years. 1 year is equal to 3.16 x 10^7 s.