51–60 of 73 posts
If this takes over and is used everywhere, in 50 years, will people become nostalgic over titanium dioxide white? Will the titanium industry be supported by the few remaining vintage white paint manufacturers? \s
I know nothing about this sort of stuff, but if this were applied to cars, would there be an increased risk of temporarily blinding other drivers on a sunny day?
It won't shine any brighter than the light that's hitting it.
Are airplanes more in need of cooling or heating? The outside temperature at cruising altitude is around -50° (roughly where the Celsius and Fahrenheit scales meet, btw), is the insulation good enough to just keep the inside at acceptable temperatures for humans?
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Nope. Silver reflectivity is about 95%, aluminum reflectivity is about 90%. So the best metallic mirrors are worse than the best white paints, even if they can be better than the frequently used white paints based on titanium white (89.5% reflectivity). Total internal reflection might be closer to 100%, but that cannot be used for the light that comes from the air on the surface of a mirror.
What I’ve seen says silver and aluminium are both a bit better than that. https://www.researchgate.net/figure/Reflectance-versus-wavel... https://www.researchgate.net/figure/Reflectance-of-Ag-Au-and... I think this better fits my observation that a clean mirror can easily be unnoticed in an environment similar in all directions, such as woodland or a messy room.
Aluminum has lower reflectivity everywhere, but it retains a high reflectivity in ultraviolet.
Silver absorbs ultraviolet, which lowers the integrated reflectivity over the complete spectrum.
A few percent difference in the total reflectivity can make a large difference in the cooling power of a paint, but a few percent difference in the reflectivity of a mirror is unlikely to be perceived visually.
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I don’t think there’s a physical difference between reflection and re-radiation, is there? Reflection is just highly organized/non-diffuse.
reflection is coherent, a single physical process. The light keeps it's phase and polarization. Re-radiation is incoherent, caused by multiple particle interactions (physical processes). So there's quite a difference in physics.
If you mixed it with Vantablack, would you get the greyest possible paint? /s
You could try buying some and find out! https://culturehustle.com/products/black-v1-0-beta-the-world... You could also mix it with the 'whitest white' https://culturehustle.com/products/white-20
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What I’ve seen says silver and aluminium are both a bit better than that. https://www.researchgate.net/figure/Reflectance-versus-wavel... https://www.researchgate.net/figure/Reflectance-of-Ag-Au-and... I think this better fits my observation that a clean mirror can easily be unnoticed in an environment similar in all directions, such as woodland or a messy room.
What counts is not the peak reflectivity from those graphs, but the integrals over the solar spectrum. Aluminum has lower reflectivity everywhere, but it retains a high reflectivity in ultraviolet. Silver absorbs ultraviolet, which lowers the integrated reflectivity over the complete spectrum. A few percent difference in the total reflectivity can make a large difference in the cooling power of a paint, but a few per…
Re >> "with an ability to reflect around 98% of incoming sunlight" Seems like a mirror would reflect even more light. Now, obviously we don't want to make the exteriors of our buildings and cars a mirror! . but it made me wonder: What's the difference between a really really really white paint that reflects 98%+ light, vs. a reflective surface? Is it that the white paint reflects the light, but in a "scrambled" form,…
Nope. Silver reflectivity is about 95%, aluminum reflectivity is about 90%. So the best metallic mirrors are worse than the best white paints, even if they can be better than the frequently used white paints based on titanium white (89.5% reflectivity). Total internal reflection might be closer to 100%, but that cannot be used for the light that comes from the air on the surface of a mirror.