On the other hand, the effects are very important when the velocities are high enough. Suppose an alien spaceship traveling at towards Earth fires a missile at the planet with speed relative to the ship. According to the Newtonian addition of velocities, a stationary observer on Earth would see the missile traveling at , which is impossible, since it would arrive before the observer even saw it coming! Using the relativistic formula, however, we actually see the missile coming at:
,
which is a much more reasonable speed, and would at least give us time to blink before being obliterated - assuming we were all glued to our telescopes when it happened.