On the flight to Madrid, while flying into the sunrise, I noticed this triangular dark area on the horizon. In my sleep-deprived state, it took me a few seconds before I realized it was the shadow of the Earth.
This shadow extends out hundreds of thousands of kilometres into space, out past the orbit of the Moon. If the shadow intersects with the full moon, we see a lunar eclipse.
The act of exploring and understanding the world and universe are such an incredible joy for me.