Ok, let's pull back from the God thing and turn on some nice, easy-listening science fiction.
Old Man's War is a damn good book, and Scalzi is a damn fine writer. Although this is technically genre writing, the syle and resonance of Scalzi's writing elevate it above the usual "It is now the year 2150, and ____________" (fill in the blank with "robots rule the earth", "apes rule the earth", "the earth is only a fond memory", etc.).
The date of the story's beginning is not specified, and it isn't important; in the future life on earth is pretty much the same as it is now - life in space is what's changed. Humanity has conquered the lightspeed barrier and colonized several other solar systems. But there is virtually no exchange of technology or information between the Department of Colonial Affairs and Earth; everything flows one way only - off planet, permanently. Colonists are young, healthy, fertile men and women from low-income nations like India and Thailand, and once they leave, they never come back.
Unless you are a serious devotee of science fiction you've probably never heard of Michael Flynn; I hadn't until a couple of years ago, and I take my science fiction very seriously. He tends to fly beneath the radar, eschewing melodramatic space opera, in favor of highly detailed, very plausible multi-threaded stories, spread out on a very large scale. Unlike many authors of the genre, he publishes only once every several years, and the level of skill, commitment and imagination that goes into each novel makes the wait worthwhile. 
