I learned this today. Vantablack is the blackest material ever made because it absorbs 99.965% of light.
Anything that you have in front of you right now is reflecting light back into your eyes. For example, my phone case is red with a brown cat on it. It is night, so there is no sunlight. The light is coming from the light on my ceiling. The photons from the light hit my phone case, which mostly reflects the wavelength of 700 nanometers, except for the bit with the cat, which reflects the wavelength of 600 nanometers.
These wavelengths hit the retina in my eye and send a signal to my brain. My brain knows that a wavelength of 700 nanometers is a bright red and 600 nanometers is more of a brown color. And this is how we see things around us and navigate our way through life. We detect the reflected wavelengths and assign colors to them.
Which basically means Vantablack is impossible to see. Vantablack is the blackest material ever made. It absorbs 99.965% of the light that hits it.
Vantablack is able to be so black because of the way it is made. It is made of a forest of carbon nanotubes. Each nanotube has a diameter of 10 nm and is 1000 nm long (1 micron). It is grown on a surface of chlorine-etched aluminium foil.
When light hits the Vantablack it doesn’t reflect directly off the surface but enters the nanotubes. Once it is inside, it gets reflected into the forest of nanotubes and cannot escape. Its energy is converted to heat.
One amazing property of the material is that it absorbs light uniformly from any angle. No matter what shapes or bumps were on the material, they wouldn’t reflect the light and would be invisible.
The name “Vantablack” comes from Vertically Aligned NanoTube Arrays + Black.
Vantablack is an amazing substance. It has many potential uses, but one of them is in telescopes, space telescopes to be exact. Astrophysicists are looking at using the material as a star shade. It would be used to shield telescopes in space from stray light. Space telescopes have to cope with glare from various light sources and they need something that is very black to absorb the glare.
Vantablack has also been released as a spray. BMW used the spray to make one of its X6s completely black. However, not anyone can buy the spray or Vantablack. The company that makes it will only supply small samples because of export regulations from the UK. BMW probably spent over a million dollars to paint their X6.
So, Vantablack is the darkest material ever made and it absorbs 99.965% of light. It is made of carbon nanotubes and the light waves get lost amongst the tubes where they are converted to energy. And that is what I learned today.
Sources
https://en.wikipedia.org/wiki/Vantablack
https://en.wikipedia.org/wiki/Carbon_nanotube
https://news.mit.edu/2019/blackest-black-material-cnt-0913
