Why is it like whis?

[Wos]

When I point a green 532nm laser up in the ceiling for example, it looks like on the video below but ofc in green...

My question is HOW does this happen?

 

[magmabeam]

Video title gives it away a bit..

 

[Blord]

The answer lies in this thread, http://laserpointerforums.com/f54/diffuse-laser-reflection-why-shimmer-64959.html :wave:

 

[Wos]

Tried to search but didnt find any thread... Thanks Blord :beer:

 

[WizardG]

The fancy technical term for this is speckle. The light from your laser starts out in phase but in a diffuse reflection the light from adjacent areas becomes phase shifted pretty much randomly.