Some Points About Time Travel And Admiralty

If the universe began to exist at time t-zero, then what becomes of a time traveler who, not knowing this, tries to travel to a time earlier than t-zero?

Does he enter a void?

Or does the entire universe including a time traveler with a reverse arrow of time begin to exist at t-zero? Thus, in terms of that reverse arrow of time, the past-ward traveling time traveler would cease to exist at t-zero?

Another possibility might be that the earliest moment, in this case t-zero, is like the northernmost point, the North Pole. Thus, someone who travels to the North Pole and keeps going travels south again but through another hemisphere. In the same way, a time traveler who travels to t-zero and keeps going would travel future-ward again but through a different volume of space.

There are at least three possible answers. A Poul Anderson story ends unexpectedly with one of these three.

I have got back into "Admiralty" - see the two previous posts - so will probably post more about this third Gunnar Heim story. Hard sf premises lead to human stories. If Heim merely blockades occupied New Europe indefinitely, then the human colonists, living off the land but cut off from supplies by the Aleriona occupation force, will run out of vitamin C and will have to surrender. Learning this from a freed prisoner, Heim must change his approach. But, despite the evidence about Aleriona intentions, the World Federation remains reluctant to wage war. Policy might be changed by the emotional appeal of a shipload of New European women and children entering the Solar System. So Heim has to smuggle a ship to the surface of New Europe concealing it from the Aleriona by hiding it behind a small asteroid that has been nudged into a collision course with the planet...

At each stage, Anderson combines a hard sf concept with a human issue.