# Ok how much energy will I need

#### physicsismylife

Well I was a registered user here before and something obviously messed up???

Anyway, I am working on this physics project and decided I want to warp the light around an object of some sort to make it appear invisable from the front.

I've been thinking about how to actually pull this off, and the only concern I have is the amount of energy I will need for this and to create a safe barrier between the object the class I am presenting.

Any idea's?

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#### MrCaN

Yea, first off your best bet is to use a super massive magnetic field, and the amount of power would be astronomical, and the object wouldn't appear invisible, it would just show up as a dark spot, or a blurred mess, because the object is reflecting light, not producing it.

#### chroot

Staff Emeritus
Gold Member
Magnetic fields don't bend light.

You'd have to create a black hole to do what you describe.

Good luck getting that past the administrators.

- Warren

#### MrCaN

Chroot you are correct that magnetic fields don't bend light, but they can change the path of light. Which is what our experimenter here is trying to do.

#### chroot

Staff Emeritus
Gold Member
Originally posted by MrCaN
Chroot you are correct that magnetic fields don't bend light, but they can change the path of light.
Wrong.

- Warren

#### physicsismylife

Hmm, yes a black hole would be convieniant(sp?) but I do not have the supplies to pull one off.

I was under the impression if I pul copper coil around the object and produce a strong electric field I could warp the light around it... or maybe warp space-time itself.

#### chroot

Staff Emeritus
Gold Member
Originally posted by physicsismylife
I was under the impression if I pul copper coil around the object and produce a strong electric field I could warp the light around it... or maybe warp space-time itself.

- Warren

#### MrCaN

What do you mean wrong, I have to question if you have studied EM at all, its not a hard connection to make, a light wave is made from both a magnetic field and a electric field, and by definition all magnetic fields will interact to one another.

#### chroot

Staff Emeritus
Gold Member
Originally posted by MrCaN
What do you mean wrong, I have to question if you have studied EM at all, its not a hard connection to make, a light wave is made from both a magnetic field and a electric field, and by definition all magnetic fields will interact to one another.
So I see you've studied electromagnetism long enough to understand that light is a wave phenomena in the electic and magnetic fields. Perhaps you should study a bit more.

- Warren

#### MrCaN

Ok Chroot, I don't want to get into a flame war so I will try to say this in small words so that you can understand. Magnetic fields can change the vacuum index, and bend the light. Now I will admit, that only correctly polarized light is effected, but like I stated earlier magnetic fields can bend light. here is a link to an interesting paper on the subject as it occurs around magnestars http://www.cita.utoronto.ca/~shaviv/preprints/lens.pdf [Broken]

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#### physicsismylife

Uhm guys, I still have to pull this off...

#### chroot

Staff Emeritus
Gold Member
Uh, good luck buddy.

- Warren

#### FZ+

Really, the closest thing I have to this is the manufacture of a new material that "flips" the field of light and causes refraction in the opposite direction to what is expected.

http://www.centredaily.com/mld/centredaily/news/5523920.htm

But as too what you want to do, I really wouldn't. If you can pull it off, a nobel prize is waiting. But I'd switch projects if I were you.

#### MrCaN

What u want isn't plausible in a classroom setting.

#### Hurkyl

Staff Emeritus
Gold Member
"Cloaking devices" have been constructed with fiber optics. While the technical, engineering, and practical concerns are probably beyond your means, you could demonstrate the idea with a clever arrangement of mirrors. A simple arrangement (which could be improved) would look like:

Code:
    | |
+---+ |
|/   /|
|     |
|  ***|
|     |
|\   \|
+---+ |
| |
The diagonal lines represent mirrors, the +, -, and | symbols are the walls of your box, and the * are where you can place an object. The illusion will obviously only happen when a person is looking directly into the tunnel on the end, but it would still look nifty!

Hurkyl

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