I was once in someone’s homemade sauna (he was a materials engineering professor, so I had high hopes for safety, but I probably wouldn’t do it again) that was basically a structure around a superheated pipe like this.
Yeah srsly, how. Its so evenly, if its not a liquid iron pipeline i cannot phantom how this happens except Photoshop. Eletric stuff is usually bolts or cables, most gas stuff isn't that hot, maybe some chemical piping but i don't know enough about chemical processing to actually guess.
Using a Google image search I found that this version of the image was apparently cropped and flipped from an older one:
Then, using Tineye I found that that version of the image was posted a bunch around 2008. One of the places it appeared was this gizmodo article which is 404'd today but was saved in the internet archive:
That article says its a form of decorative interior lighting, so I would guess that this is a colored fiberglass pipe with some kind of light inside it. Given that it was 2008 it might've even been a fluorescent tube.