Ejecting from an aircraft moving at speeds greater than the speed of sound (mach 1: 750 miles per hour / 1,207 kph) can be very dangerous. The force of ejecting at those speeds can reach in excess of 20 Gs -- one G is the force of Earth's gravity. At 20 Gs, a pilot experiences a force equal to 20 times his or her body weight, which can cause severe injury and even death.