This is the first one I did that summer and it's one of my favorites. The gears aren't as obvious, they're more integrated into the ground. My goal was simply to have a vast landscape with mixed industrial and natural elements in the light of a dying sun. The intense colours in the sky are supposed to be beautiful but at the same time indicating pollution in the air.
Here's another one done entirely from my imagination. It brings you inside a cave that's got possibly poisonous water/liquid and a single source of light in the distance.
This one has a Victorian lady lost in the woods, surrounded by mysterious darkness (or trees, or hooded figures) with no technology to help her. Just a source of light in the canopy above.
I just like my brushstrokes in this one and the sense it creates that you're zooming into this earth-like planet.
This is simply gears thrown out into space. The bit of galaxy behind them is based on a real picture of the Whirlpool Galaxy. The reddish bubbles of hot gas are where stars are born.
If you want to see the amazing beauty of outer space then you should take a look at Deep Space: The Universe from the Beginning by Stuart Clark. The whole thing is stunning, beautifully printed, oversized pictures with interesting info.