Spiffy title. I really thought hard about it.
First off, nope. Not even close to being a natural sky but its my world and I can make it do what I want. Skies should be this cool when the sun is setting. It might make people pay more attention. Maybe this is what a Martian sunset looks like. Use your imagination. I can make it look realistic. Part of HDR photography is making it look like whatever. I wanted fiery skies. Who knows? Tomorrow the sky may be purple. There are no rules so go with what you feel. That is unless someone is paying you then go with what they want.
For reference. This was shot off my balcony at the Hotel Palacio Del Rio in San Antonio while I was there. I believe this is the first HDR I have shot with my 80-300mm lens which is why its compressed as it is with the buildings. Still, it works with the sun being framed between them and the sky causing them to silhouette like that. I still like my version which clearly is me on Mars shooting from my Martian base into the Martian sky. Then again, could be the jet lag and holiday hangover and going back to work talking.