On the physics StackExchange site people are trying to figure how and why these branching structures formed. The two questions can be found here and here. The latter had no cooling fans and was situated in an unventilated cupboard. There are many processes that could explain such structures without them being a bacterial colony, for example by Diffusion-limited-aggregation as explained in my answer here. To me it looks like this could be a bacterial colony. Is there any way to rule this out or say with precision that this is a bacterial colony?
I think some organic material and humidity could latch on to the irregular edges upon which bacteria could then grow in a warm environment.
- What ways are there to tell from just a picture if this is a bacterial colony or not?
- What ways are there to tell if this is a bacterial colony or not if you have the structure at hand?
- What ways are there to rule out or say that this is some kind of fungus or living thing if you have the structure at hand?
The second pic was taken by Wossname:
"the equipment is in a temperate climate in a non-aircon area of an office building near the external door. In high summer it would get to probably 40 Celcius and 85% or more relative humidity in my estimation. It's an area of the building that people most definitely don't loiter in during July/August. :)"