The portal in the sky, or, The other day

So, the other day, late in the day, we took the dogs for a walk at the reservoir as usual. All was as it often is, the air was cool, the wind was strong and the dogs were having a great time. As the night began to fall and the sunset gained colour, we noticed a spiral-like, galaxy shaped swirl in the sky. We watched it for quite a long time because not only did it change colour often, becoming more intense--like a fire--but it looked like a galaxy. Then, as time progressed, it looked like a giant nebula, more spectacular than any of the photos I've seen from the Hubble. I told Darren that there must be stars forming in that cloud. After some time, the cloud-nebula began to look like a CG version of a portal to another universe or time...or even another dimension. Soon, the colours changed again, becoming more and more like the water in a glass jar after rinsing watercolour brushes fifty times. I did not know that nature could create that colour.