PDA

View Full Version : Invisibility



golfinguy4
11-11-2002, 07:09 PM
How realistic is this? Basically, if a material were able to absorb all light waves at it, it would be a big black whatever, kind of like how stealth planes absorb radar waves. However, if it were able to emit light waves similar to the area around it, it would be invisible. Is this possible?

-KEN-
11-11-2002, 07:22 PM
::coughs:: The philadelphia project. The truth is out there...!!!

::Gets dragged off::

correlcj
11-11-2002, 07:26 PM
Originally posted by golfinguy4
How realistic is this? Basically, if a material were able to absorb all light waves at it, it would be a big black whatever, kind of like how stealth planes absorb radar waves. However, if it were able to emit light waves similar to the area around it, it would be invisible. Is this possible?

The government has that type of nanotechnolgy...they are called chamelon suits. They built that type of suit technology after the movie predator, which was a great movie BTW. i dont completely understand if it emits, refracts and bends light in anyway but the technogy is real. They keep that like Operation Hush! Hush! But cool huh? BTW, whats your fav futbol team?

BMJ
11-11-2002, 07:57 PM
yes, I heard of this too... they've tested it in counter-terrorism scenarios so that a group of people can sneak up on a compound without being seen... from what I saw it wasn't perfect, but it made them VERY hard to see!

golfinguy4
11-11-2002, 08:03 PM
Originally posted by correlcj
BTW, whats your fav futbol team?

For the MLS, the Revolution.
National teams: USA
Euro League Teams: Real Madrid (they are definately stacked and fun to watch, especially since Ronaldo signed)

I wish I could see more Euro league games. They are so much better than MLS. The only problem is you have to get special cable packages in the US to even get a few of them.

face_master
11-11-2002, 11:35 PM
::coughs:: The philadelphia project. The truth is out there...!!!

::Gets dragged off::Cool, someone else knows about this. Is a really cool story. Its in one of my conspiracy books. Here's some info (http://www.cowan70.freeserve.co.uk/miscellaneous/philadelphia_experiment_01.htm)


:: Gets dragged off ::

novacain
11-12-2002, 03:25 AM
Did you read about the bank robber in Iran (no kidding true story, Iread it on www.abc.com.au under news)

He was sold some 'spells' to make himself invisible. Pinned them on his arms and went into a bank and took money out of peoples hands.

Was overpowered quickly.

The police are now looking for the 'sorcerer' who sold him the 'spells'.




Any body want to buy a used stealth suit?

adrianxw
11-12-2002, 03:41 AM
>>>
However, if it were able to emit light waves similar to the area around it, it would be invisible.
<<<

Such a scheme could only work if either the viewing angle was fixed, or the background against which the object was present was an unbroken solid colour which could be matched.

In general, their have been schemes to render objects less visible. I remember seeing a demonstration whereby a tank was covered in electric light bulbs. When upon the ridge of a hill or similar, the light emitted tended to make the tank disappear into the sky, however, as soon as it was viewed against the ground, it looked, of course, like a ridiculous christmas tree.

Captain Penguin
11-12-2002, 02:31 PM
I saw a news post on /. about MIT being paid to research a new project for the US Military: biosuits for soldiers. The article stated that the aim of the project was to make footmen run faster and longer and jump higher and farther etc, and it could also bend light around it, rendering it nearly invisible

http://slashdot.org/article.pl?sid=02/03/14/1611216&mode=thread&tid=126

hk_mp5kpdw
11-12-2002, 02:57 PM
An excerpt of something I found that relates to this topic and is something I remembered hearing about years ago:

There was a secret stealth design placed on the anti-submarine aircraft or World War 2. These aircraft would search for submarines by flying patterns at low levels over sectors of the ocean, the enemy sub lookouts would be able to see the airplanes up to fifteen miles away. This may sound strange, but the solution was to place landing lights all along the leading edge of the wings and turn the lights on. This would hide the airplane by matching the amount of light emissions from the airplane to the amount of light from the normal background brightness. Instead of having the submarine lookouts see a dark object on the horizon at fifteen miles, the approaching airplane would not be visible until it was three to five miles away. With this short range of detection, the submarine was not able to dive before the airplane was on top of the sub.

Yoshi
11-12-2002, 03:17 PM
You'll need very good tech / electric bills to achieve invisibility.

700 posts!! In 1 year that is :)

Fountain
11-12-2002, 03:18 PM
Of course, how fantastic would it be to have the power to become invisible at will?

Get working on it guys.:p

Imperito
11-12-2002, 03:46 PM
My impression of the matter is that a covering that mimiced the coloration of the background would only work at a fixed angle of sight. for example...




(Blue stuff) (White stuff)
\ /
\ /
\ /
\ /
Bob
/ \
/ \
/ \
/ \
/ \
Phil Steve



Wiith Bob being invisible, the bottom of bob would have to be botth blue and white, or else either phil or steve would be able to see him.

As for "light bending" you have other consequences. Something that is transparent to photons would not create disturbances in the electromagnetic spectrum, and therefore be invisible. This would be good.

BUT

Our eyes require that our retinas absorb photons. Without this we would not be able to see. This would be bad. Any other spectra of electromagnetic waves we were transparent to would cause problems as well, because we rely on many of them to operate.

A more practical form of "invisibility" which does work is to simply absorb all photons that you are not backlit by. For example, wearing tan in the desert or wearing black at night.

TheUnheardHuman
11-12-2002, 10:30 PM
im invisble! well pretty close

Brian
11-13-2002, 02:00 AM
It would get quite complicated, as you can see from my diagram. The other side of Bob's invisibility suit would have to produce rays going in the exact same direction, amplitude and frequency as every ray which struck the opposite side of him. (blue rays represent artificial rays) Mr Y would be in bob's shadow if the invisibility suit didn't work and mr x and mr z wouldnt be able to see him. Mr Z should be able to see mr X, etc.

ammar
11-13-2002, 12:40 PM
I'm not very sure but I think black holes are like this.
They have a very powerful gravity that even light can't escape it.

salvelinus
11-13-2002, 02:34 PM
You can't see inside a black hole, at least past the event horizon, but you can see where a black hole is by the energy created as matter rushes into a/o around it. It would also be like looking into a dark doorway. You can't see inside but you can see a door is there.
As for bending light, I don't see how that would work. Once the light is bent, it would have to be re-bent around an object in an exactly parallel manner, or you'd have a cone of invisibility. It would also have to do this in a spherical manner to be invisible from all 3-D sides.


Cone
of
\ Invisibilty / Bent Light Rays
\ / <----|
\ /
\ /
\ /
\ X X /
\ /