I just finished Odyssey by Jack McDevitt.

Odyssey is set in one of McDevitt's common worlds, where humanity seems to be almost alone in the universe, with no other advanced civilizations around and most of the threats come from the natural world or mysterious things, like the "Omega Clouds", but it is very different from most of his other novels. There is a lot more use of the politics of this world, which seem oddly similar to our own, with the future equivalent of NASA facing being shut down or under-funded. Meanwhile, some ships have started to see strange objects along their routes and no one is sure what they are.

By the end of the novel, there is more revealed, but McDevitt doesn't insist on wrapping everything up neatly in his novels and this is no exception.

The first half of the novel, which focuses more on the political struggles, is below average for McDevitt, but the second half comes on strong and gets a lot better, continuing McDevitt's streak as one of the more interesting modern SF writers.