Not Brownian movement, just hot air rising. I wear glasses, not a microscope
The conversion layer between cold and hot air will slightly bend light, therefore you can see the air shimmer and even mirror on a straight hot road.
At the time I was into LEDs etc. and was looking at my taillight when I saw something move in the corner of my eye. It was the hot air escaping out of the top of the front wheel well against a background of vertical fine stripes (reedlike plants.)
We have a pair of ear thermometers; my wife disliked the first one. I'll ask her if I can use it; it is hand-held and it measures infrared, right?
She just read this, said "You guys are out of your minds". That's approvement, I guess
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2011 Honda Insight + HID, LEDs, tiny PV panel, extra brake pad return springs, neutral wheel alignment, 44/42 PSI (air), PHEV light (inop), tightened wheel nut.
lifetime FE over 0.2 Gmeter or 0.13 Mmile.
For confirmation go to people just like you.
For education go to people unlike yourself.