After an initial leap into the future, he' was now traveling backward through real time.
Francis' mother travels backward in her memory from the present.
The ascent wasn't very fast, but they were traveling backward.
He believed it would make it possible to travel backward in time.
Sometime during the next century, a means of traveling backward in time is invented.
Madonna travels backward in the show to the beginning of her career, the time before she was encumbered with the need to do good.
Instinctively, his glance traveled backward toward the steel door of the room.
That means the jaunt has begun: she's traveling backward in time.
So instead of traveling progressively backward, the early music people turned around and began moving forward again.
The ship happened to be traveling backward at several times the speed of sound, and air could not move away from before it.