Flash forward to today, and Brin has written Existence, which is easily as large, and again builds its world from the bottom-up, fragmenting its narrative across a cast that includes - among others - an elderly astronaut now on orbital clean-up detail, a mischievous science fiction writer, a climate-displaced Chinese scavenger and a trust-fund baby with a penchant for illegal space flight. This time, while environmental matters still hover at the edges, the main focus lies with humanity's lonely position in the cosmos. This apparent loneliness doesn't last many pages into the novel, when an unexpected find in Earth orbit answers the question "are we alone?" firmly in the negative. Or seemingly so, at any rate. But the answer comes with caveats, and as the novel progresses it becomes clear that the answer is also plural.
As I was refreshing my memory and writing the above, I was struck how much the two novels share - at least in summary. What they don't share is that while Earth's epic page-count makes it an engrossing page-turner, Existence's comparable length makes it a gruelling chore. In part, I think one of the reasons is that all of Earth's scattered narratives serve the whole: an all-encompassing treatment of environmentalism. By contrast, Existence is much less coherent, and serves up amateur rocketry, (virtual) space aliens, muddled extropian thinking, uplifting animals and settings or situations that, while interesting on their own, read as disconnected in the novel. For instance, the wealth contrast between the scavenging lifestyle of Bin and the super-entitled, playboy adventures of Hacker makes sense at first in world-building, but Brin really doesn't do anything with it. And, by the end, this sort of detail has been completely left behind.
As a result, while Existence is sporadically interesting and enjoyable, it is ultimately a tedious read. Were it about half its length - a feat of editing that wouldn't be as difficult to achieve as one might imagine - its sins would be much more forgiveable. As it stands, Existence is only intermittently clever, and while it has some interesting ideas, it spaces them widely within a plodding millstone of a book. If I turn to Brin again, it will only be when his page count drops to the vicinity of 300.