There seems to be quite a few clever types on this ‘ere forum, so I thought one of you might be able to tell me what I am seeing on my desk. Sun is shinning through my window on to my desk. In the area that is lit up on my desk I can see what looks like smoke rippling upwards i.e. towards me on the flat surface. There is water collected outside the window. If I look with the naked eye at the window I cannot see anything. But the sun highlight on my desk definitely shows the ‘smoke stuff’. Is this water vapor? ? ???

Heat haze?

https://en.wikipedia.org/wiki/Mirage#Heat_haze

ahhhh… I thought you had to be looking over a hot surface over a distance for a heat haze… but obviously not.

I would hazard a guess it’s the ‘shadow’ of the heat haze you are seeing – the variation in light intensity is too dim for you to perceive if you look directly at the bright light in the window, but the desk provides a dark enough surface for it to show up?

It’s warm air rising past the window from the vertical wall beneath, heated by solar radiation. If the surrounding air is a lot cooler the warmer air will create turbulence as it rises. Warm air is thinner than cool air and refracts light less, which is why you see a rippling effect.

As an aside, I’ve just ordered this book, which looked absolutely fascinating when I dipped into it in Waterstones:

Interesting. Have read his book “The Natural Navigator” and am currently reading “Walker’s Guide to Outdoor Clues and Signs” (titles may be slightly paraphrased). Trouble is, they’re fascinating when you read them, but I’m damned if I can remember any of it when it comes to putting it into practice.

cool… i’ve been educated, cheers…

Tristan Gooley *smirk*

In the area that is lit up on my desk I can see what looks like smoke rippling upwards i.e. towards me on the flat surface.

My guess would be the heat rising from a radiator under the window… Hot air retract s light differently to cold air, which is why you see the wibblies.

dogmatix desk…