Beautiful phenomenon but I can't found any explanation around the net

[Pougatchev]

Hi all!!!

 

I take this photo during an hydrographic mission near devil's island in french Guyana around august/september 2013, I just look my album when I saw this pics, any idea about what can do that?

 

The phenomenon was also viewable by eyes, not a lense phenomenon.

 

 

Thank's :thumbup:

 

I have look around the net but i don't see any similar one :helpsmilie:

[VincentLaw]

I would guess it is similar to what is happening in this picture:

 

 

It looks like an optical phenomenon, not an aerodynamic one. It is probably from cloud tops blocking some of the sunlight coming over the horizon.

[Suchacz]

1st pic:I agree, it looks like a shadow of something huge which is hidden over the horizon...

[Isegrim]

Nothing special just Aliens.:book:

[MACADEMIC]

Shadow of a very high Cumulunimbus cloud beyond the horizon line around the time of sunrise/sunset, such clouds very frequent around the equator.

 

MAC

[aeliusg]

What time of day was this taken?

[KLR Rico]

I've seen contrails cast shadows in the same way, pretty spectacular effect if you ask me!

[SkateZilla]

what you are seeing is rays in the upper atmosphere, and something blocking part of the light (cloud, mountain, building, plane, etc etc).

 

 

Pretty much the same way you see Sun rays in the forest obstructed by tree branches.

[71st_Mastiff]

Low sunrise, casting a shadow. That is all, no phenomenon.

[Joe Kurr]

They're called 'crepuscular rays', and as described above, are caused by sunlight being blocked by clouds or other objects.

[Pilotasso]

They're called 'crepuscular rays', and as described above, are caused by sunlight being blocked by clouds or other objects.

 

...like a flying saucer :ufo:

[Joe Kurr]

...like a flying saucer :ufo:

 

No, those would completely block out the sun :)

[Pougatchev]

Thank's for all those explanations, this photo was take around the end of the day.

[Moa]

SkateZilla and JoeKurr are correct. The lighter part of the sky is caused by scattering of light from the sun (physically this is known as Rayleigh and Mie scattering - from atmospheric molecules and dust particles, respectively).

 

The dark streak is where light from the sun is blocked by a cloud or terrain feature. This means that light is blocked before it can be scattered toward you. Hence there are dark streaks.

 

The term for the brighter shafts on either side is 'crepuscular rays' because they are most often seen when the sun is low in the morning and evening ('crepuscular' refers to dawn and twilight, and applies to animals that are active at that time, as well as light effects; Christopher Hitchens also described himself as crepuscular when he was sick with cancer).

 

Such light rays are an important effect for realistic computer graphics. Implementations such as those of Bruneton and Neyret's "Precomputed Atmospheric Scattering" also produces such effects:

http://hal.archives-ouvertes.fr/inria-00288758

 

See:

http://proland.imag.fr/

 

Silviu Andrei also implemented this, and it looks fantastic:

${1}

 

I've included the links in case the Eagle Dynamics team want to implement this in EDGE (although they probably already have). I'm certainly working on such effects in my own simulator.

Edited September 3, 2014 by Moa

[Flagrum]

Just another random example of the phenomenon I found interesting to see.