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I read that mirrors absorb only a small amount of light(1-2%). And recently MIT engineers developed the "Blackest Black"(blacker than Vantablack) which reflects only 0.005% of the light. Let's say we create a perfectly reflective mirror which absorbs 0% of the light and a Black object which reflects 0% of the light. If we were to combine the properties of both these objects can we achieve invisibility?

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    $\begingroup$ Why would the "black" thing become invisible? Wouldn't you be able to see it as "black"? $\endgroup$ – FakeMod May 31 at 13:16
  • $\begingroup$ Okay my question briefly was, if we were somehow able to create an object which neither absorbs light nor reflects it, can it be invisible? $\endgroup$ – dharani kumar May 31 at 13:46
  • $\begingroup$ Where would the light go then? $\endgroup$ – FakeMod May 31 at 13:49
  • $\begingroup$ My question is not about what happens to the light, but the concept of invisibility, if it can be achieved this way. Maybe the light passes through it? $\endgroup$ – dharani kumar May 31 at 13:55
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    $\begingroup$ My windows neither absorb nor reflect substantial amounts of light. They are largely invisible, and I've got the dead birds to prove it. $\endgroup$ – WillO May 31 at 14:28
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The trick with invisibility is to arrange the flow of light so that when someone looks towards you they see whatever is behind you. This can be achieved by two methods:

either

  1. a chameleon-like rapid colouring and patterning of your clothing to make it look like the scenery behind---with a 3d hologram-like effect for the best results.

  2. a powerful lens-like medium, or actively adjusted light tube, that steers the light from behind you around your body and then emits it towards the viewer as if it had just traveled in a straight line.

Obviously both are difficult, especially for a viewing from all directions at once, but there have been some modest successes with special materials. You can look it up to explore further. In science fiction they seem mostly to go for the second solution. But the main point is that science fact does allow this sort of thing in principle, and it is not about either absorption or reflection. It is about steering the light, like water flowing around an obstacle.

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  • $\begingroup$ There has been some interesting work on achieving invisibility with special materials as you mentioned, albeit with limited success. Linking a nice TEDx talk on the subject:. youtu.be/v9d-EBgro50. $\endgroup$ – Dvij D.C. May 31 at 16:52

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