Imagine you're part of a starship's crew. You've been away for 15 years. Feeling, perhaps, a little homesick, you return to your starting point. Except it's not 15 years later where you came from, it's 86,985 years later. Call it a penalty for trying to violate the laws of physics. When you jump from point to point in space, you may age only a minute or so, but if the jump covered 300 light years, to the world outside your ship the trip took 300 years.
Now imagine the planet you left was Earth. A lot of things can happen in nearly 87,000 years. An advanced technological civilization can vanish so completely that no one has any idea it ever existed. For instance, what if you left an earth with two moons, and a very large island in the middle of the Atlantic Ocean, and returned to a world with one moon and no island? Drop a moon, even a small, irregularly shaped one only 60 KM at its widest point, onto that island and you get worldwide extinctions or near-extinctions, the total collapse of civilization as the relative handful of survivors struggle just to survive, and the legend of an advanced island culture wiped out by angry gods.
This is the basic premise of Returning, the new novel I'm finishing up, and expect to see published by mid-year. The starship Warrior, sent off into deep space in the year 525 of the Gehunite Era, returns and parks itself next to the Sagan Space Platform on 2nd April, 2126. The world they find is obviously different that the world they left. Arzucalda, the former island nation memorialized in the Atlantis legends, is gone, along with the small second moon that presumably destroyed it. The United Kingdom has become the dominant power in space exploration, though that's limited to this solar system. The United States has essentially withdrawn from space, or, for that matter, from the rest of the world.
The US has thrown out the Constitution, and enacted a new one. The President can now make law, and overriding a presidential enactment requires the votes of 90% of Congress. As that means 90% of the membership, and not just of the members present, it almost never happens. There is no more House and Senate, only a unicameral Congress. The Supreme Court has lost the power to rule on constitutionality, and so can't override enacted laws. No one tries to sneak across the northern or southern borders, which are secured by triple rows of barbed-wire fencing and automated minigun turrets that target anyone trying to cross (but, don't worry, they're programmed to ignore anything that isn't human, so they only shoot people, not deer, armadillos, and jaguars).
Having, or performing, an abortion is punishable by death. So is any homosexual conduct (but only by men, lesbians go to reeducation facilities). Anyone earning money is required to pay a faith tax of 10% of their net income, with the money going to whatever church they designate. If the taxpayer isn't a Christian, their faith tax is still due, but the money goes into a pool and is evenly distributed among the churches in that district. Blasphemy is punishable by prison, but only if it's against the Christian God. You can say whatever you want about Allah, Vishnu, or any of the others. Sometimes people just disappear. If you look at satellite images anywhere in the United States, so did one corner of Wyoming, though from any other country's internet it looks like a huge camp of some sort. A former evangelist has been President for 29 years.
As little as possible is being reported on the returning starship. What is reported suggests this is either a British hoax, or the starship came from somewhere else. According to official US government policy, the world is no more than 10,000 years old, evolution is a fraud, and everything in Genesis is literally true. Climate change is still a hoax. Coastal problems are obviously caused by subsidence, not rising ocean levels.
Returning is a fascinating science fiction novel, set in a future that seems more and more possible with every passing day. If you want to be among the first to read it, and maybe get a few other perks as well, contribute to my Indiegogo Campaign. I'm giving away ebooks, paperbacks, t-shirts, polo shirts, baseball caps, and maybe even some special edition leather (or leatherette) bound copies.