April 5, 2035
Earth Departure
09:30 Universal Time
The Rock
Not much happened in the vicinity of the rock as it followed its long, looping path around the Sun. Nothing of particular interest came anywhere near it. Interplanetary space between Earth and Mars was a near-perfect vacuum, averaging no more than five atoms—atoms—per cubic centimeter. Even if the rock had been sentient and possessed of the latest scientific instruments, it would never have noticed the occasional hydrogen atom that collided with it during its seemingly endless journey around the Sun.
Newton’s Laws were at work. A body in motion remains in motion—unless some outside force acts upon it.
The rock hurtled along as it had for fifteen million years, undisturbed in its orbit between Mars and Earth. However, it was moving blindly toward a spot that, although currently empty, would soon be occupied by another object.
Newton’s inexorable laws would dictate that these two objects would meet in a violent collision. The second of the two objects was not an inert chunk of rock, but rather it had been purposefully created and powered by the nuclear fires of its engines and the ingenuity of humankind.