There are materials with negative refractive indexes.

IWETHEY v. 0.3.0 | TODO

1,095 registered users | 0 active users | 0 LpH | Statistics
Login | Create New User

Welcome to IWETHEY!

Post #174,212

by Another Scott

9/14/04 1:32:33 PM

There are materials with negative refractive indexes.

Lots of weird things are being discovered these days.

[link|http://physicsweb.org/articles/world/16/5/3/1|Physics Web].

I think c will stand as a limit for a while though. :-)

Cheers,
Scott.

Post #174,217

Picture of deSitter

9/14/04 1:53:55 PM

Re: There are materials with negative refractive indexes.

Neat, I'll have to look at that some more.

Just to close this issue - C is *not* a barrier or a limit or even the speed of anything in particular. It's a parameter that characterizes the actual world.

Note that Euclidean geometry has exactly such a parameter - but it is imaginary! That is, in relativistic geometry we can think of the equation

x^2 - (ct)^2 = 0

and factor this to

(x-ct)(x+ct) = 0

so either x/t = c or x/t = -c. The parameter then represents the relative scale of the space to the time axis.

Now, it turns out that metric geometry (with a Pythagorean-like theorem) is a special case of projective geometry, and that the special type of metric geometry (Euclidean or pseudo-Euclidean = relativistic) is determined by the equation for a "degenerate conic", which is one that looks like

x^2 + y^2 + ... = 0

Euclidean plane geometry is then characterized by the equation

x^2 + y^2 = 0

which can be factored into

(x+iy)(x-iy) = 0

The characteristic parameter of Euclidean geometry is i, the imaginary unit! The points x and y satisfying this equation are called the "circular points at infinity". So, in a sense, Euclidean geometry has a thing called "infinity" that is such that you can never get closer to it. This is exactly analogous to the parameter c in relativity, which has a speed that can never be attained. Thus

relativity = the light cone
Euclidean geometry = the points at infinity

-drl

Where the hell is everybody? - (inthane-chan) - (43) - Sept. 13, 2004, 10:48:25 AM EDT

Easy... - (admin) - Sept. 13, 2004, 10:56:43 AM EDT

Light is slow. Universe is big. Catastrophes happen. - (Another Scott) - (2) - Sept. 13, 2004, 11:17:08 AM EDT

Not if you believe Von Neumann - (ben_tilly) - Sept. 13, 2004, 11:32:41 AM EDT

Looking for radio signals is probably futile. - (Andrew Grygus) - Sept. 13, 2004, 11:44:18 AM EDT

Re: Where the hell is everybody? - (deSitter) - (2) - Sept. 13, 2004, 04:55:19 PM EDT

So what's your answer? -NT - (inthane-chan) - (1) - Sept. 13, 2004, 04:57:57 PM EDT

Don't think it's a valid question at this point - (deSitter) - Sept. 13, 2004, 05:04:22 PM EDT

Where? Well.. the Why has been done by Calvin & Hobbes - (Ashton) - Sept. 13, 2004, 05:16:22 PM EDT

The speed of light is too low. - (static) - (24) - Sept. 14, 2004, 12:29:44 AM EDT

It is clear the speed of light must be exceeded. - (Andrew Grygus) - (20) - Sept. 14, 2004, 12:35:34 AM EDT

Not a joke! -NT - (deSitter) - Sept. 14, 2004, 02:03:27 AM EDT

I believe and nearly always have... - (folkert) - (10) - Sept. 14, 2004, 11:05:12 AM EDT

The problem with C is that it's a hard limit. -NT - (pwhysall) - Sept. 14, 2004, 11:16:36 AM EDT

I don't think we'll ever exceed C myself. - (inthane-chan) - (5) - Sept. 14, 2004, 11:21:51 AM EDT

OT: What's C++ all about, then? :) -NT - (Meerkat) - (4) - Sept. 15, 2004, 12:03:00 AM EDT

:-) -NT - (Another Scott) - Sept. 15, 2004, 12:21:01 AM EDT

Demonstrating that you can't - (ben_tilly) - Sept. 15, 2004, 10:44:48 AM EDT

Hmmm - (imric) - Sept. 15, 2004, 10:48:58 AM EDT

Simple - (admin) - Sept. 15, 2004, 10:58:15 AM EDT

Re: I believe and nearly always have... - (deSitter) - Sept. 14, 2004, 11:22:50 AM EDT

There is no evidence that they affect each other - (ben_tilly) - Sept. 14, 2004, 11:27:36 AM EDT

Replying to my own... to address the others. - (folkert) - Sept. 14, 2004, 12:04:18 PM EDT

Metaphysics wise - (ChrisR) - (7) - Sept. 14, 2004, 11:30:04 AM EDT

Re: Metaphysics wise - (deSitter) - (6) - Sept. 14, 2004, 12:03:09 PM EDT

No... - (ben_tilly) - (3) - Sept. 14, 2004, 12:08:02 PM EDT

Re: No... - (deSitter) - (2) - Sept. 14, 2004, 12:55:53 PM EDT

There are materials with negative refractive indexes. - (Another Scott) - (1) - Sept. 14, 2004, 01:32:33 PM EDT

Re: There are materials with negative refractive indexes. - (deSitter) - Sept. 14, 2004, 01:53:55 PM EDT

Well, if we can't speed up light.... - (ChrisR) - (1) - Sept. 14, 2004, 12:08:53 PM EDT

That would be one of my favourite passages. :-) -NT - (static) - Sept. 14, 2004, 09:12:32 PM EDT

It's not the getting there, it's slowing down enough to look - (drewk) - (1) - Sept. 14, 2004, 12:37:14 AM EDT

Right - (deSitter) - Sept. 14, 2004, 02:11:13 AM EDT

Re: The speed of light is too low. - (deSitter) - Sept. 14, 2004, 02:01:32 AM EDT

Space is big. - (pwhysall) - (5) - Sept. 14, 2004, 12:40:45 AM EDT

I believe the technical term for it is ... hyarge -NT - (drewk) - Sept. 14, 2004, 12:49:29 AM EDT

Not so big - (ben_tilly) - (2) - Sept. 14, 2004, 02:27:15 AM EDT

Question about that theory - (drewk) - (1) - Sept. 14, 2004, 11:41:48 AM EDT

The latter - (ben_tilly) - Sept. 14, 2004, 12:02:22 PM EDT

I thought it was a long way to the chemists. But that's - (Meerkat) - Sept. 14, 2004, 03:28:52 AM EDT

Don't know enough - (JayMehaffey) - (1) - Sept. 14, 2004, 01:21:13 AM EDT

Re: Don't know enough - (deSitter) - Sept. 14, 2004, 02:04:39 AM EDT

Might like some MMORPGs - (Meerkat) - (1) - Sept. 14, 2004, 03:30:59 AM EDT

Your .sig is oddly appropriate. :) -NT - (inthane-chan) - Sept. 14, 2004, 10:52:02 AM EDT

My brain hurts thinking about how you know all of that.
317 ms