Space-Time Cloak Could Hide Actual Events

An anonymous reader writes "My first thought was, a hypothetical space-time invisibility cloak? That must be what hypothetical crime-fighting Einstein wears when he wades into the fray! Sadly, the researchers who thought up this trick to 'hide events' say that the metamaterials we have on hand will only allow for a nanoscale demonstration at best."

Ffs

[Anonymous Coward]

Fuckin jounalists, I'm sure every scientist tells them metamaterials are not going to lead to invisibility powers, but they put it into every fuckin story until it's overplayed bullshit central.

How not to be seen . . .

[PolygamousRanchKid]

The seminal work on this was produced in the UK in the late 60's or early 70's, and shown on the PBS network in the USA, who frequently interrupted the program to beg for money: http://en.wikipedia.org/wiki/How_Not_to_Be_Seen [wikipedia.org]

Re:Ffs

[delinear]

Even though it's a joke it's probably not far from the truth. A dry scientific explanation is never going to make front-page on the millions of blogs, while "INVISIBILITY CLOAK NOW MONTHS AWAY!" is a shoe-in (unfortunately). Of course, you also then get a subset of scientists overstating their case to garner exactly this response, which doesn't help matters at all.

Re:Better article

[rtb61]

However it is logically demonstrable that time does not exist. For time to exist, the present is the infestimally small sliver between the past and the future, so infinitesimally small as to logically be zero, the past of course no longer exists and the future is yet to exist, hence for time to exist the universe can not.

Re:Better article

[XxtraLarGe]

However it is logically demonstrable that time does not exist. For time to exist, the present is the infestimally small sliver between the past and the future, so infinitesimally small as to logically be zero, the past of course no longer exists and the future is yet to exist, hence for time to exist the universe can not.

Sounds oddly similar to Zeno's Dichotomy Paradox. Thanks to calculus [wolfram.com], the issue has been solved.

Re:Better article

[uglyduckling]

Yup, and in fact the integer 1 is the infinitesimally small sliver between the infinity 0..1 and 1..2, so logically 1 does not exist. Therefore, logically, nothing exists.

Re:Ffs

[DJRumpy]

The first question I had is how they are going to speed light up beyond the speed of light? I know it's theoretically possible for that to happen around gravity wells from black holes as they drag actual space-time around the event horizon, but how would they do this with a piece of fabric regardless of the machinery embedded in it?

Re:Better article

[mcgrew]

Time does indeed exist. It is the measure of entropy.

Re:Photon Mass

[AstrumPreliator]

If photons did have mass then they wouldn't be traveling the speed of light. The speed of light would still be a constant, but light wouldn't actually travel at that speed. As far as an alternative to dark matter, I'm not really qualified to answer that. According to wikipedia the upper bound for the mass of a photon is 1 x 10^(-18) eV/c^2 which is miniscule. For reference an electron has a mass of about .5 MeV/c^2. Considering dark matter is supposed to take up 80% of all matter in the viewable universe, I'd have to guess no. Like I said though, I'm not a physicist so take this with a grain of salt.

Re:Photon Mass

[locofungus]

No - photons cannot account for the "missing mass". It's called "dark matter" because we know that it (whatever it is) does not interact with the electromagnetic force.

Indirectly, we can experimentally confirm that photons have a rest mass of zero from the fact that unless EM is exactly inverse square then there would be an electric field inside a hollow conductor. (proving this is relatively straight forward for a perfect sphere - I understand that it can be proved for a general closed conductor but that's maths far beyond what I'm capable of)

http://personal.rhul.ac.uk/UHAP/027/PH2420/PH2420_files/notes/04.pdf [rhul.ac.uk] (page 6)

Basically it's a galvanometer connected between an isolated conductor that is inside a closed conductor and the closed conductor. The conductor is then driven with a few kV at the resonant frequency of the galvanometer. Any deflection at all would indicate that EM isn't exactly inverse square and one possible explanation would be that photons do not propogate at c.

However, any result like this would be so disruptive to all known physics that pretty much every physicist would assume that there was a fault with the experiment.

Tim.