I found the explanation
I've seen it before and his errors start right from 0:16 where he says, "Taking advantage of the fact that the atmosphere is full of moisture and that it is acting like a lens."
Some of the troubles with this explanation are:
- The atmosphere is not "full of moisture". Even at 100% humidity at 20°C 1 m3 of air has a mass of about 1.225 kg and contains only 17.3 gm of water.
So it is certainly not "full of moisture".
- That small amount of water is in the form of water vapour which has a lower refractive index than even air, so humid air refracts light less than dry air.
For example, at "normal pressure" and 20°C, the refractive index of dry air is about 1.000271 and that of 100% humid air is about 1.000270, virtually no change!
- Sunsets and the suns rays under clouds occur under dry or humid conditions.
Water might refract light much more than air, but water vapour does not.
Sure,
Rob Skiba gets refraction because he
inserts a plastic lens in the sun's path.
But in reality, there is nothing but air to refract the light and that will bend the light from the sun by roughly 0.5°
in the wrong direction!
They do say, "A little knowledge is a dangerous thing".
Yet we certainly do get this sort of thing before sunrise and after sunset:
Clouds lit on the underside before sunrise | | Sun's rays shining up on clouds before sunrise | | Clouds lit from underneath near Toogoolawah at Sunset |
And upward slanting shadows on the underside of clouds with the sun lower than the peak of Mount Rainier:
Maybe the sun really does rise from behind the horizon and set behind the horizon.