You mean
https://www.google.com.au/maps/@-28....!3m1!1e3?hl=en, looks like an aircraft in flight while the satellite was taking a picy.
I imagine the white "shadow" underneath is an in-focus version of the bright spot you often get down-sun when you look for your own shadow.
I've always wondered what the mechanism is, for that bright spot:
- It is certainly an area where you can't see the shadows of trees/grass/etc, the shadows are hidden by the object, so that area looks brighter.
- Is the sun focused by less dense air around the aircraft? (Would less dense air even do that?)
- Is it some kind of grate/diffusion effect?
- And/or something completely different?