# one of the technique to make an object invisible..what do you think? will it work?
**URL:** https://boards.straightdope.com/t/one-of-the-technique-to-make-an-object-invisible-what-do-you-think-will-it-work/611653
**Category:** Great Debates
**Created:** [February 3, 2012, 2:59pm UTC](https://boards.straightdope.com/t/one-of-the-technique-to-make-an-object-invisible-what-do-you-think-will-it-work/611653 "2012-02-03T14:59:59Z")
**Posts on this page:** 20
**Page:** 1
### Author:  [@Rutika\_Kulkarni](https://boards.straightdope.com/u/Rutika_Kulkarni)
#### Post date: [February 3, 2012, 2:59pm UTC](https://boards.straightdope.com/t/one-of-the-technique-to-make-an-object-invisible-what-do-you-think-will-it-work/611653/1 "2012-02-03T14:59:59Z")
The formula for speed is speed = distance/time. Speed is equal to the
change in distance over the change in time. This is the measurement
for speed.
According to this equation if we take a speed of light as 3_10^8 m/s^2
and distance of a object from the observer as 27cm
We get 3_10^8 = 27_10^-2
30_10^-2/3\*10^8=time
According to this equation we get 1nano second as a time which light
needs to reflect and reach to observer
So if we use theory of physics and keep an small object at the distance of 30cm
With lots of lights surrounded to it giving 1 nanosecond time for each
light to flash only…
If we switch on the lights flashes within 1 nanosecond only…light
leaving from the source will successfully reach to the object but it
will not b able to come to our eye…in this way we will blow hundreds
of lights.Here if light will not be able to come to our eye and we
will not be able to see that object. That means the object will be
invisible.
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### Author:  [@PacifistPorcupine](https://boards.straightdope.com/u/PacifistPorcupine)
#### Post date: [February 3, 2012, 3:20pm UTC](https://boards.straightdope.com/t/one-of-the-technique-to-make-an-object-invisible-what-do-you-think-will-it-work/611653/2 "2012-02-03T15:20:02Z")
I do not understand your post after “30_10^-2/3_10^8=time.” I think you are saying that if the light is turned off before it travels from the source, to the object, then to the eye, the object will be invisible. This is nonsensical. You are assuming that the photons that have already left the source magically vanish when the light source is turned off.
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### Author:  [@John\_Mace](https://boards.straightdope.com/u/John_Mace)
#### Post date: [February 3, 2012, 3:25pm UTC](https://boards.straightdope.com/t/one-of-the-technique-to-make-an-object-invisible-what-do-you-think-will-it-work/611653/3 "2012-02-03T15:25:13Z")
You came up with a system to make something invisible by controlling the light it receives. Why not just turn the off, and it’s invisible permanently?
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### Author:  [@yorick73](https://boards.straightdope.com/u/yorick73)
#### Post date: [February 3, 2012, 3:34pm UTC](https://boards.straightdope.com/t/one-of-the-technique-to-make-an-object-invisible-what-do-you-think-will-it-work/611653/4 "2012-02-03T15:34:36Z")
> [@John\_Mace](#):
>
> You came up with a system to make something invisible by controlling the light it receives. Why not just turn the off, and it’s invisible permanently?
That’s way too boring…and does not involve the need for cool physics equipment!
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### Author:  [@The\_Hamster\_King](https://boards.straightdope.com/u/The_Hamster_King)
#### Post date: [February 3, 2012, 4:25pm UTC](https://boards.straightdope.com/t/one-of-the-technique-to-make-an-object-invisible-what-do-you-think-will-it-work/611653/5 "2012-02-03T16:25:20Z")
> [@Rutika\_Kulkarni](#):
>
> If we switch on the lights flashes within 1 nanosecond only..light leaving from the source will successfully reach to the object but it will not b able to come to our eye.
Turning off the light stops the production of new photons, but doesn’t eliminate the photons previously produced by the light and already in flight. They’ll still bounce off the object and into your eye.
So, no, it won’t work.
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### Author:  [@Rutika\_Kulkarni](https://boards.straightdope.com/u/Rutika_Kulkarni)
#### Post date: [February 3, 2012, 5:08pm UTC](https://boards.straightdope.com/t/one-of-the-technique-to-make-an-object-invisible-what-do-you-think-will-it-work/611653/6 "2012-02-03T17:08:11Z")
> [@The\_Hamster\_King](#):
>
> Turning off the light stops the production of new photons, but doesn’t eliminate the photons previously produced by the light and already in flight. They’ll still bounce off the object and into your eye.
>
> So, no, it won’t work.
ya i know that if light will emit from one source then it is definatly going to reach the observer but before that i am again switching on the another light in this way i will blow thousands of light on after another very fastly? then?
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### Author:  [@PacifistPorcupine](https://boards.straightdope.com/u/PacifistPorcupine)
#### Post date: [February 3, 2012, 5:11pm UTC](https://boards.straightdope.com/t/one-of-the-technique-to-make-an-object-invisible-what-do-you-think-will-it-work/611653/7 "2012-02-03T17:11:35Z")
> [@Rutika\_Kulkarni](#):
>
> ya i know that if light will emit from one source then it is definatly going to reach the observer but before that i am again switching on the another light in this way i will blow thousands of light on after another very fastly? then?
Then what? You just illuminated the object from a different source, which will only make it _more_ visible, not _less._
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### Author:  [@Leaffan](https://boards.straightdope.com/u/Leaffan)
#### Post date: [February 3, 2012, 5:14pm UTC](https://boards.straightdope.com/t/one-of-the-technique-to-make-an-object-invisible-what-do-you-think-will-it-work/611653/8 "2012-02-03T17:14:24Z")
There is [work in progress](http://www.sciencedaily.com/releases/2011/08/110808202502.htm) to use the slowing of light as a means of invisibility.
It’s a short article.
> [@](#):
>
> An undergraduate student has overcome a major hurdle in the development of invisibility cloaks by adding an optical device into their design that not only remains invisible itself, but also has the ability to slow down light.
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### Author:  [@Rutika\_Kulkarni](https://boards.straightdope.com/u/Rutika_Kulkarni)
#### Post date: [February 3, 2012, 5:24pm UTC](https://boards.straightdope.com/t/one-of-the-technique-to-make-an-object-invisible-what-do-you-think-will-it-work/611653/9 "2012-02-03T17:24:12Z")
What do you think do Bermuda Triangle exists? If yes then What is the reason behind it?
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### Author:  [@Leaffan](https://boards.straightdope.com/u/Leaffan)
#### Post date: [February 3, 2012, 5:27pm UTC](https://boards.straightdope.com/t/one-of-the-technique-to-make-an-object-invisible-what-do-you-think-will-it-work/611653/10 "2012-02-03T17:27:03Z")
> [@Rutika\_Kulkarni](#):
>
> What do you think do Bermuda Triangle exists? If yes then What is the reason behind it?
Yes it exists. It’s an area borderd by Florida, Bermuda, and Puerto Rico.
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### Author:  [@Czarcasm](https://boards.straightdope.com/u/Czarcasm)
#### Post date: [February 3, 2012, 5:37pm UTC](https://boards.straightdope.com/t/one-of-the-technique-to-make-an-object-invisible-what-do-you-think-will-it-work/611653/11 "2012-02-03T17:37:42Z")
> [@Rutika\_Kulkarni](#):
>
> What do you think do Bermuda Triangle exists? If yes then What is the reason behind it?
Is this a separate topic? You might want to start a new thread in the proper forum.
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### Author:  [@Marley23](https://boards.straightdope.com/u/Marley23)
#### Post date: [February 3, 2012, 5:39pm UTC](https://boards.straightdope.com/t/one-of-the-technique-to-make-an-object-invisible-what-do-you-think-will-it-work/611653/12 "2012-02-03T17:39:20Z")
> [@Czarcasm](#):
>
> Is this a separate topic? You might want to start a new thread in the proper forum.
[She did.](http://boards.straightdope.com/sdmb/showthread.php?t=640786) So the discussion of invisibility technology can continue here.
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### Author:  [@Czarcasm](https://boards.straightdope.com/u/Czarcasm)
#### Post date: [February 3, 2012, 5:40pm UTC](https://boards.straightdope.com/t/one-of-the-technique-to-make-an-object-invisible-what-do-you-think-will-it-work/611653/13 "2012-02-03T17:40:49Z")
> [@Marley23](#):
>
> [He did.](http://boards.straightdope.com/sdmb/showthread.php?t=640786) So the discussion of invisibility technology can continue here.
I just saw that after I posted. Never mind.
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### Author:  [@Czarcasm](https://boards.straightdope.com/u/Czarcasm)
#### Post date: [February 3, 2012, 5:44pm UTC](https://boards.straightdope.com/t/one-of-the-technique-to-make-an-object-invisible-what-do-you-think-will-it-work/611653/14 "2012-02-03T17:44:24Z")
> [@Rutika\_Kulkarni](#):
>
> …i will blow thousands of light on after another very fastly? then?
This phrase confuses me. Do you mean “turn on thousands of lights”?
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### Author:  [@Rutika\_Kulkarni](https://boards.straightdope.com/u/Rutika_Kulkarni)
#### Post date: [February 3, 2012, 5:54pm UTC](https://boards.straightdope.com/t/one-of-the-technique-to-make-an-object-invisible-what-do-you-think-will-it-work/611653/15 "2012-02-03T17:54:19Z")
> [@Czarcasm](#):
>
> This phrase confuses me. Do you mean “turn on thousands of lights”?
yes means the same
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### Author:  [@Czarcasm](https://boards.straightdope.com/u/Czarcasm)
#### Post date: [February 3, 2012, 5:58pm UTC](https://boards.straightdope.com/t/one-of-the-technique-to-make-an-object-invisible-what-do-you-think-will-it-work/611653/16 "2012-02-03T17:58:02Z")
> [@Rutika\_Kulkarni](#):
>
> yes means the same
Then what do you mean by “turning them on very fastly(fast)”? How fast?
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### Author:  [@Rutika\_Kulkarni](https://boards.straightdope.com/u/Rutika_Kulkarni)
#### Post date: [February 4, 2012, 6:21am UTC](https://boards.straightdope.com/t/one-of-the-technique-to-make-an-object-invisible-what-do-you-think-will-it-work/611653/17 "2012-02-04T06:21:10Z")
> [@Czarcasm](#):
>
> Then what do you mean by “turning them on very fastly(fast)”? How fast?
they will turn on for 1 nanosecond
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### Author:  [@jjimm](https://boards.straightdope.com/u/jjimm)
#### Post date: [February 4, 2012, 6:39am UTC](https://boards.straightdope.com/t/one-of-the-technique-to-make-an-object-invisible-what-do-you-think-will-it-work/611653/18 "2012-02-04T06:39:19Z")
Even a light turned on for one nanosecond will emit photons, which will hit the object, bounce off it, and allow it to be seen.
I’m sensing that English isn’t your first language. I think there might be something I’m missing from your explanation, because right now it doesn’t make any sense at all.
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### Author:  [@Sage\_Rat](https://boards.straightdope.com/u/Sage_Rat)
#### Post date: [February 4, 2012, 8:19am UTC](https://boards.straightdope.com/t/one-of-the-technique-to-make-an-object-invisible-what-do-you-think-will-it-work/611653/19 "2012-02-04T08:19:54Z")
Even ignoring refraction of light off of other objects and back towards our target object, the idea doesn’t work in any useful sense. You’d end up making the world look like a zebra with concentric rings of black radiating out from the light source, each one of the thickness of the object that you are trying to hide. While we wouldn’t see the object you’re trying to hide, it would be so obvious that someone was doing something weird that you’d end up bringing more attention to the issue than if you’d just left the target out in the open and hoped no one noticed.
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### Author:  [@Great\_Antibob](https://boards.straightdope.com/u/Great_Antibob)
#### Post date: [February 4, 2012, 4:40pm UTC](https://boards.straightdope.com/t/one-of-the-technique-to-make-an-object-invisible-what-do-you-think-will-it-work/611653/20 "2012-02-04T16:40:11Z")
Well, I still see 1 major problem in two parts.
There are other sources of light. If you did this is broad daylight with a bunch of rapidly strobing lights, it wouldn’t make anything invisible. Why should it?
As mentioned in previous posts, this is called “darkness” not invisibility. You are basically using the laws of probability to keep the number of photons that reach the eyes down. That’s not “invisibility”. That’s just plain darkness and assumes there are no other sources of light.
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