Short answers, pulled from the story.
Sir William Herschel discovered infrared radiation in 1800 while experimenting with sunlight and thermometers. He found invisible rays beyond the red end of the visible spectrum that caused temperature increases.
A substance like silver has very low emissivity at 0.02 while asphalt reaches nearly 0.98. Emissivity measures how effectively a material radiates heat compared to a theoretical perfect emitter called a black body.
The first commercial thermal imaging camera appeared in 1965 for inspecting high voltage power lines. This device marked the beginning of widespread industrial use for thermal technology.
Government personnel utilized thermography to detect suspected swine flu cases during the 2009 pandemic by monitoring physiological activities like fever responses non-contactly. Physiological activities can be monitored in human beings and other warm-blooded animals through skin thermal maps.
The first luxury car equipped with automotive night vision was the 2000 Cadillac DeVille. A thermal camera integrated directly into smartphones appeared later in the Cat S60 model released on the 1st of January 2016.