Use "nebular" in a sentence

1. ’ She could see him now – as the room faded – shrouded in mist, or perhaps it was a nebular

2. ’ His image was fading now, into the nebular, until there was nothing of him

3. A red and yellow nebular had formed, fading to purple on the edge

4. "She's thinking about Kant and the nebular hypothesis," I decided to myself, having once heard some men with long beards talking of both those things, and they all had had that same far-away look in their eyes