A student is calibrating a projectile launcher to be used in a laboratory experiment. The launcher is placed on the ground and set to fire a ball at an angle \( \theta \) above the horizontal across a level field. In the first calibration trial, the ball is launched with an initial speed \( v_0 \) and travels a horizontal distance \( D_1 \) before hitting the ground. In the second calibration trial, the launcher is adjusted to fire the ball at the same angle \( \theta \) but with an initial speed of \( 2v_0 \), resulting in a horizontal distance \( D_2 \). What is the ratio of the horizontal distance \( D_2 \) to the horizontal distance \( D_1 \)?