Poul Anderson's Tau Zero (1970) has been my first encounter with hard sf. But this is not as spicy as it sounds. Hard science fiction is science fiction that takes its science seriously, or uses science as an integral plot element. This would distinguish hard sf from space operas, visionary fiction, social criticism, or those novels that are just zany romps through future worlds. Perhaps a few of the books I've been reading were "hard" to some degree, but I never took any of the science elements seriously. Mr. Anderson, however, is a trained physicist, and he is able to write persuasively about the predicament of his space pioneers.
What he writes about relativity and space travel all seems plausible, but then again I am an easy mark since I know nothing about the serious science at work here. Before reading this book all I knew about "tau" was that it was a letter in the Greek alphabet that appeared in crossword puzzles and came in handy while playing the various Boggle-style games I play online. (The fact you can add an "s" makes it doubly useful ) Apparently it is also a measure of speed when discussing the possibility of spacecraft approaching the speed of light. The lower the tau the faster the craft is traveling. Tau Zero would be the speed of light itself.
The fifty scientists, along with the crew members, have signed on for a trip aboard the Leonora Christine to check out an earth-style planet in a nearby galaxy. What for them will be a five year journey will use up 30 years of earth time. Even if they just go and come back they will find an earth void of most of the acquaintances and changed in God knows how many ways. If the planet is habitable, they are to stay, and eventually more colonists will join them.
Guess what? Something goes wrong. They pass through a previously undetected gassy nebula, and the jolt knocks out their retro rockets. In other words they continue to accelerate but have no means of stopping when they get to where they are going.
But these are smart people, remember. Plans are made to go off course to an empty-enough realm of space that shutting off their radioactive shields will not incinerate the ship, make the needed repairs, and then go on...somewhere...some nice galaxy that may have a habitable planet.
Meanwhile, life aboard the Leonora Christine becmes a soap opera. It is the duty of these brave pioneers to choose up partners they can start procreating with on their new planet. As tension mounts with the various catastrophes, the ship becomes a kind of intergalactic Peyton Place. Who's going to be with whom? Who's restless with their first partner? What clandestine affairs are taking place? Is mutiny brewing?
This all plays out with the level of character development you expect from a TV series like one of the Stargate franchises. And that is how it should play out. Tau Zero is 188 pages long. The last thing I would have wanted while reading it is another 100 or so pages of serious character development, which Mr. Anderson, and I do not mean this in a mean way, would have probably botched.
The cool stuff is the scientific predicament. They make the repairs, but there is no where to go. The ship travels faster and faster. Earth, or at the very least human life, almost certainly no longer exists. They are by now hundreds of millions of years into the future, and as their speed increases so does their mass. The Leonora Christine is not longer a spaceship that goes really fast, it has taken on the mass of a small star, and those little bumps the passengers occasionally feel are the galaxies they burst through, leaving who knows what level of destruction in their wake.
Then guess what happens? (Should I be posting "spoiler alerts:" on these blog posts?) They have traveled so far, so fast, that the universe has begun to shrink, just like scientists always said it would, although I don't think they necessarily say that anymore. The Leonora Christine now has to stay along the edge of this contraction so they can find the sweet spot that will allow them to ride out the next big bang.
Think about it. Riding out the next big bang while trying to get back together with your old girlfriend. That is one hell of a plot device.
There is a happy ending. They survive the big bang, and they are still traveling so fast that all they have to do is find a new galaxy about five billion years old and look for a habitable planet. It may be unrealistic to think they get lucky their first time out, but Mr. Anderson cuts them a break. Tau Zero concludes on a green planet, with twenty-five couples ready to start making babies for a new civilization.
Poul Anderson is an author who takes up several shelves in the sf section of any used bookstore. Although I enjoyed this, I am not inclined to read any further into his oeuvre. I don't mind sf writers with right wing political agendas or the misogynist attitudes of their day. But I cannot forgive Mr. Anderson for being a founding member of The Society for Creative Anachronism.