The distance from earth to the center of our galaxy is about 19,000 ly (1 ly = 1 light year = 9.47 10¹⁵ 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 yr is equal to 3.16 10⁷ s.)