>Point 3 goes against normal behavior of hot metals, which emit infrared or visible light as they get hotter.
You're right. People refer to it as 'transparent' because it begins to glow the same color as the jet plume under afterburner use.
https://gizmodo.com/this-is-an-image-of-the-very-last-test-o...
The "moving parts" may be due to heat waves moving through the air (see also: mirage at a distance)