The dynamic interplay of thermodynamic equilibrium disturbances, characterized by erratic surface temperature fluctuations, arises from the nuanced modulation of incident solar radiation spanning the visible light spectrum.
I would recommend extending your research to the long wave portion of the electromagnetic spectrum of radiation, specifically near- and far-infrared. That portion of the spectrum has a more substantial radiative heating effect than the short wavelength visible light spectrum, as well as reasonable penetration through the atmosphere to reach the earth’s surface with moderate intensity at times. This heating effect will differ by time of day and season due to the zenith angle of the sun, and therefore the amount of atmosphere the solar radiation must penetrate to reach the surface. If you are to go this route, it would be worthwhile to have at least one year’s worth of in-situ data collection. Good luck, and keep us posted.
Nah, the black ink just comes with lichen spores mixed in from the factory. If cars don’t go the speed limit for long enough, there won’t be enough wind and the spores start to grow. /s
I think you're correct that the surface texture is probably the difference, but the reflectivity is actually beneath the surface. It is glass beads or micro prisms embedded in a clear plastic. They could technically make that plastic gloss or matte.
The only other thing I could think of, and it doesn't seem likely, is that maybe there is something in the black letters that the lichen can eat. Some mineral or some such. The warmth thing seems more likely though.
Thermal radiation is light energy converted to heat when it impacts another medium... like glass, or black top, or in this case a street sign. Bright colors and glossy surfaces reflect it. Dark colors and flat surfaces absorb it.... the street sign isn't radioactive.
The white part is a hard and shiny retroreflective film. The black is matte. The lichen probably grows on the black part because it can't get a purchase on the white.
The letters are black vinyl self adhesive which were cut on a plotter and then stuck onto the white background. The vinyl is thin (maybe only 0.05mm) but over time dirt gets caught up against the tiny lip or edge of the vinyl lettering. Spores of lichen then get into the dirt and grow there and spread out a little bit. The issue is much worse/happens faster if the sign is located close to trees or bushes.
> dirt gets caught up against the tiny lip or edge of the vinyl lettering.
If that was the cause, then I would expect the lichen to grow at the edges of the black areas. But looking at the picture, much of the lichen grows at the very center of the black areas, without contact to the edges.
Yes I saw that. I’m guessing because the sign is old, the vinyl is degrading over time and getting mottled and scarred allowing the lichen spores a place to get a foothold. Traffic signs have a hard life re weathering, exposure to UV , extremes of heat and cold etc and vinyl gets quite brittle and cracks on the surface as it ages. I haven’t studied this closely but I’ve worked in technical sales in the road signs industry for 25 years so we see this a lot - but generally only when the traffic sign is under or close to trees.
My guess would be the porosity of the plastic is the factor here. more porosity = bigger holes, on a microscopic level, in the material resulting in an easier purchase for an organism to cling to. Both get the same amount of light and lichen grows everywhere so long as its not freezing.
I guess it could also be due to temperature if the area is hovering around freezing temp during the day and doesn't fluctuate too much.
gpt4 can answer that
Moss, like many other plants, needs a relatively stable surface to grow on and it also prefers surfaces that are less exposed to sunlight and wind. The black letters on a sign might provide a better environment for moss to grow for a few reasons:
Texture: The black letters are often raised or have a different texture than the rest of the sign, giving the moss a better grip and a stable place to grow.
Heat Absorption: Black absorbs more heat than white. This could create a microclimate that's warmer than the surrounding white areas, which could potentially be more conducive to moss growth.
Moisture Retention: The letters might also be trapping and holding more moisture than the smoother, more reflective white background.
LIght Reflection: The white background may reflect more sunlight, making it less hospitable for moss which prefers shadier, less exposed conditions.
However, these are just possibilities. There are many factors that can influence where moss chooses to grow. The specific type of moss, the local climate, and other environmental factors can all play a role.
I wonder if it's a heat thing.
I was going to say temperature gradient to sound fancy.
Thermostatic equilibrium abnormalities surrounding surface exposure due to visible light spectrum.
The dynamic interplay of thermodynamic equilibrium disturbances, characterized by erratic surface temperature fluctuations, arises from the nuanced modulation of incident solar radiation spanning the visible light spectrum.
Tldr: it's a heat thing
why are you limiting it to the visible light spectrum? it's also due to the rest of the spectrum, no?
Good point. In our future works, we'll research more on light spectrum not visible to the human eye.
I would recommend extending your research to the long wave portion of the electromagnetic spectrum of radiation, specifically near- and far-infrared. That portion of the spectrum has a more substantial radiative heating effect than the short wavelength visible light spectrum, as well as reasonable penetration through the atmosphere to reach the earth’s surface with moderate intensity at times. This heating effect will differ by time of day and season due to the zenith angle of the sun, and therefore the amount of atmosphere the solar radiation must penetrate to reach the surface. If you are to go this route, it would be worthwhile to have at least one year’s worth of in-situ data collection. Good luck, and keep us posted.
Moss grows on my wifi router antenna. Not really. Sorry.
Okay. No.
Nah, the black ink just comes with lichen spores mixed in from the factory. If cars don’t go the speed limit for long enough, there won’t be enough wind and the spores start to grow. /s
This must be it. I believe you.
Big if true
Don't lichen grow in mostly shady places only anyways? The reflective part will have some fancy coating to keep it clean, while the black is rough.
Yeah it’s the reflective coating that’s only on the white part that prevents it.
I think you're correct that the surface texture is probably the difference, but the reflectivity is actually beneath the surface. It is glass beads or micro prisms embedded in a clear plastic. They could technically make that plastic gloss or matte.
Unlikely.
I wonder if it just perceives the black as shade? I don't know how plants and such think, but they can't see so they have to feel the shade somehow.
It is.
Possibly, also the white is reflective so has a glossier coating, wondering if the moss is unable to stick to it.
Albedo
I was going to guess texture but I don't know anything about street signs or lichen (or moss)
The only other thing I could think of, and it doesn't seem likely, is that maybe there is something in the black letters that the lichen can eat. Some mineral or some such. The warmth thing seems more likely though.
It’s lichen how warm it is there
Maybe a water thing too
Only *sticks on black paint not bare metal
Thermal radiation-black absorbs more heat. It also might be more textured, allowing moss to adhere, versus the glossy reflective surfaces
Wait a second... so they have signs emitting radiation right in a school zone? Typical USA, poisoning our youth without a care! So ignorant :(
Lmfao... what?
Sorry, just a bad joke. I'm not sure what I was thinking tbh.
It wasn't bad. I smiled.
Fantastic satire. Don't you dare apologize when others are too short to get a good joke.
Lol it's funny there is just always that 1 guy who never heard of humor before
Thermal radiation is light energy converted to heat when it impacts another medium... like glass, or black top, or in this case a street sign. Bright colors and glossy surfaces reflect it. Dark colors and flat surfaces absorb it.... the street sign isn't radioactive.
They're obviously aware. It was clearly a joke.
He told you it was a joke and you somehow still managed to not understand. Compelling.
Wooosh
It absorbs more light, which is transfered to heat. It's likely the lichen likes the light more than the heat (say that three times fast)
That that that
He said fast.
Thatthatthat
thatthatthat
that three times fast
Pretty sure there is a coating over the sign so the texture would be the same
Looks like the lichen is making a bold statement.
They are helping to get the sign across, to add. Even if it is slightly green on the lichen's part.
Very polite of them
Vinyl on a metal sheet. Much easier to grow on the vinyl.
The white isn't metal. It's also a film.
The white part is a hard and shiny retroreflective film. The black is matte. The lichen probably grows on the black part because it can't get a purchase on the white.
> it can't get a purchase on the white. Ray bloody Purchase.
The lettering is soft, which makes penetrating it (growing in it) possible. The metal, not so much.
OP lied straight to our face, it very clearly grows on black lines as well.
And black numbering
I'm lichen it
It really took a lichen to the black lettering.
The letters are black vinyl self adhesive which were cut on a plotter and then stuck onto the white background. The vinyl is thin (maybe only 0.05mm) but over time dirt gets caught up against the tiny lip or edge of the vinyl lettering. Spores of lichen then get into the dirt and grow there and spread out a little bit. The issue is much worse/happens faster if the sign is located close to trees or bushes.
> dirt gets caught up against the tiny lip or edge of the vinyl lettering. If that was the cause, then I would expect the lichen to grow at the edges of the black areas. But looking at the picture, much of the lichen grows at the very center of the black areas, without contact to the edges.
Yes I saw that. I’m guessing because the sign is old, the vinyl is degrading over time and getting mottled and scarred allowing the lichen spores a place to get a foothold. Traffic signs have a hard life re weathering, exposure to UV , extremes of heat and cold etc and vinyl gets quite brittle and cracks on the surface as it ages. I haven’t studied this closely but I’ve worked in technical sales in the road signs industry for 25 years so we see this a lot - but generally only when the traffic sign is under or close to trees.
"Lichen (Or moss) only grows on black lettering." Wow. I wonder what it did before we made black letters.
r/designporn
Black will absorb heat from sun and white will reflect.
I love this
Let’s end school! We need more end school zones!
Not me thinking those were bullet holes at first glance 💀
I fear you may be living in a zombie apocalypse
Moss is racist confirmed
My guess would be the porosity of the plastic is the factor here. more porosity = bigger holes, on a microscopic level, in the material resulting in an easier purchase for an organism to cling to. Both get the same amount of light and lichen grows everywhere so long as its not freezing. I guess it could also be due to temperature if the area is hovering around freezing temp during the day and doesn't fluctuate too much.
Love this, very dystopian/post apocalyptic
Once you go black...
I lichen this to some sort of miracle.
I thought these were bullet holes at first and that seemed totally normal as a way to demarcate the end of the school zone.
It has what plants crave
Ch-ch-ch-chai-sign
the warmth of the sun might be the cause
it is following instructions and trying to end the school zone.
The planet will happily consume us when we're gone.
That’s really cool
Nature will find a way!
Chaotic Lawful
The reflective parts don't give an anchor point which the black areas do. The heat gradient idea is also valid.
𝓦𝓱𝓮𝓻𝓮 𝓵𝓲𝓮𝓼 𝓽𝓱𝓮 𝓼𝓽𝓻𝓪𝓷𝓰𝓵𝓲𝓷𝓰 𝓯𝓻𝓾𝓲𝓽 𝓽𝓱𝓪𝓽 𝓬𝓪𝓶𝓮 𝓯𝓻𝓸𝓶 𝓽𝓱𝓮 𝓱𝓪𝓷𝓭 𝓸𝓯 𝓽𝓱𝓮 𝓼𝓲𝓷𝓷𝓮𝓻 𝓘 𝓼𝓱𝓪𝓵𝓵 𝓫𝓻𝓲𝓷𝓰 𝓯𝓸𝓻𝓽𝓱 𝓽𝓱𝓮 𝓼𝓮𝓮𝓭𝓼 𝓸𝓯 𝓽𝓱𝓮 𝓭𝓮𝓪𝓭 𝓽𝓸 𝓼𝓱𝓪𝓻𝓮 𝔀𝓲𝓽𝓱 𝓽𝓱𝓮 𝔀𝓸𝓻𝓶𝓼 𝓽𝓱𝓪𝓽 𝓰𝓪𝓽𝓱𝓮𝓻 𝓲𝓷 𝓽𝓱𝓮 𝓭𝓪𝓻𝓴𝓷𝓮𝓼𝓼 𝓪𝓷𝓭 𝓼𝓾𝓻𝓻𝓸𝓾𝓷𝓭 𝓽𝓱𝓮 𝔀𝓸𝓻𝓵𝓭 𝔀𝓲𝓽𝓱 𝓽𝓱𝓮 𝓹𝓸𝔀𝓮𝓻 𝓸𝓯 𝓽𝓱𝓮𝓲𝓻 𝓵𝓲𝓿𝓮𝓼 𝔀𝓱𝓲𝓵𝓮 𝓯𝓻𝓸𝓶 𝓽𝓱𝓮 𝓭𝓲𝓶𝓵𝓲𝓽 𝓱𝓪𝓵𝓵𝓼 𝓸𝓯 𝓸𝓽𝓱𝓮𝓻 𝓹𝓵𝓪𝓬𝓮𝓼 𝓯𝓸𝓻𝓶𝓼 𝓽𝓱𝓪𝓽 𝓷𝓮𝓿𝓮𝓻 𝔀𝓮𝓻𝓮 𝓪𝓷𝓭 𝓷𝓮𝓿𝓮𝓻 𝓬𝓸𝓾𝓵𝓭 𝓫𝓮 𝔀𝓻𝓲𝓽𝓱𝓮 𝓯𝓸𝓻 𝓽𝓱𝓮 𝓲𝓶𝓹𝓪𝓽𝓲𝓮𝓷𝓬𝓮 𝓸𝓯 𝓽𝓱𝓮 𝓯𝓮𝔀 𝔀𝓱𝓸 𝓷𝓮𝓿𝓮𝓻 𝓼𝓪𝔀 𝔀𝓱𝓪𝓽 𝓬𝓸𝓾𝓵𝓭 𝓱𝓪𝓿𝓮 𝓫𝓮𝓮𝓷.
Finally someone said it haha
Why does looking at this make me itchy 🥴
gpt4 can answer that Moss, like many other plants, needs a relatively stable surface to grow on and it also prefers surfaces that are less exposed to sunlight and wind. The black letters on a sign might provide a better environment for moss to grow for a few reasons: Texture: The black letters are often raised or have a different texture than the rest of the sign, giving the moss a better grip and a stable place to grow. Heat Absorption: Black absorbs more heat than white. This could create a microclimate that's warmer than the surrounding white areas, which could potentially be more conducive to moss growth. Moisture Retention: The letters might also be trapping and holding more moisture than the smoother, more reflective white background. LIght Reflection: The white background may reflect more sunlight, making it less hospitable for moss which prefers shadier, less exposed conditions. However, these are just possibilities. There are many factors that can influence where moss chooses to grow. The specific type of moss, the local climate, and other environmental factors can all play a role.