Noun. 1. invariant-a feature (quantity or property or function) that remains unchanged when a particular transformation is applied to it. characteristic, feature-a prominent attribute or aspect of something; the map showed roads and other features; generosity is one of his best characteristics.
The part of the sun that is going to emit the most visible light is going to be the Photosphere.he photosphere is the layer of the sun that emits visible light.  The light is emitted by hydrogen atoms and is bright red. Edit. Share to: Answered. In Astronomy.
Solar radiation. Solar radiation is radiant energy emitted by the sun, particularly electromagnetic energy. About half of the radiation is in the visible short-wave part of the electromagnetic spectrum. The other half is mostly in the near-infrared part, with some in the ultraviolet part of the spectrum [1].