Dr Karl

They're either heavier or lighter, more dense or less dense.

And the fumes consist of molecules between carbon chains between, say, 6 and 12 carbons in a row.

So they are more or less dense, but you don't see them because you've got a busy background.

But if you look at the ground, the sun will shine through them and it will be bent.

And occasionally it will be bent away from the straight line, vertical, or towards it.

But either way, you'll find variations in brightness.

So that's what you can pick.

You're picking the variations in brightness on the ground as light is being either concentrated towards one area, and if it's concentrated to one area, there's less of it in another area.

And the thing is that it moves around.

This is also what you see when you're driving on a country road.

And you happen to see a bit of water on the road ahead of you.

What you're seeing is light from the blue horizon, from the blue sky, landing on the road, which is warm, and then being curved upwards to your eyeball as you drive in the car.

and the heat is not particularly even, and so it ripples.

And so you're seeing what looks like a bit of something brighter than the road, which is black, and you don't notice it as blue, and you're sort of getting some sort of brightness, and it varies.

So you go automatically, oh, there's water on the road, and no matter how far I ride, I drive, I never get to it.

Thanks so much, Lockie.

Yes.

So if you've got the time, I'd recommend a book maybe 30 or 40 years old called Girdle, G-O-E-D-E-L, Escher, E-S-C-H-E-R, the guy who did all those drawings, wasn't he?

Or there's some stairs that keep on going up and up and up and there's waterfalls going left and right.

Girdle, Escher and Bark.