Like, by now they've made it clear that all of his scenes are happening the past, during his seven year disappearance. I'll even go as far as to say that the gold statue of him that's in the Millenium Clock headquarters **is** him ("Why'd you make him so old?" (c) Laurie). That's likely what crashed on the land that Lady Trieu bought in the beginning of episode 4.

I've thought that Dr. Manhattan put him there as punishment. But was it Lady Trieu to get him out of the way while she makes the clock and takes over the world? That seems a little too obvious.

They also made it a point to have Will remind Angela that Dr. Manhattan can be multiple places at once, so is he on Europa/Mars? (him destroying the castle in the first episode)

And what's the purpose of the clock? Friend thinks it's something that can destroy Dr. Manhattan. Or Keene if he becomes Manhattan. The prevailing theory is that it's a time machine that Lady Trieu wants to use to stop the squid/Vietnam/Dr. Manhattan from being created. I would be really disappointed if that we the case.