&gt; Heat vision.  [...] MWIR is neither heat, nor is it light. It’s both<p>No, it isn&#x27;t. The &quot;infrared light is heat&quot; statement is casually-useful but technically-false,  which means it backfires and harms people when they start learning more about physics.<p>IR radiation is not the intrinsic heat-content of the matter emitting it. Infrared is simply a particular set of wavelengths which happens to be prominent for temperatures which are &quot;hot&quot; for us just because we evolved on this small rocky planet which has a certain baseline temperature.<p>Go ask some icy crystalline aliens or ones powered by low-grade nuclear reactions what they think about &quot;heat radiation&quot; and you won&#x27;t get the same answer.