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129 comments

RE: post (2, Insightful)

alphatel (1450715) | more than 3 years ago | (#34266370)

I will post my reply using my spacetime browser but you won't see it until several nanoseconds later!

Re: post (4, Funny)

JustOK (667959) | more than 3 years ago | (#34266404)

all fine until the spacetime moderators show up.

Re: post (2, Funny)

Cwix (1671282) | more than 3 years ago | (#34266412)

Ooooo how do I get that type of mod points?

Re: post (2, Funny)

Vernes (720223) | more than 3 years ago | (#34266916)

Reply to articles not yet created. -1 Reply to articles on websites not yet created -10 Reply to articles on websites on an internet not yet created -existence Erasure from existence is one hell of a ban.

Re: post (2, Funny)

Stingray454 (1942828) | more than 3 years ago | (#34266428)

Indeed, things usually take a turn for the worse when a pissed of Jean Claude Van Damme comes knocking on your door.

Re: post (0)

Anonymous Coward | more than 3 years ago | (#34267134)

let's pretend this never even happened

Minkowski you bastard (4, Insightful)

Adambomb (118938) | more than 3 years ago | (#34266400)

mwahaha! if i'm never a part of events intersecting the light cone i dont exist!

oh shiii-

Ffs (1, Interesting)

Anonymous Coward | more than 3 years ago | (#34266406)

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.

Re:Ffs (2, Insightful)

JustOK (667959) | more than 3 years ago | (#34266430)

Maybe we just can't see the ones that get it right.

Re:Ffs (3, Interesting)

delinear (991444) | more than 3 years ago | (#34266598)

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:Ffs (2, Interesting)

DJRumpy (1345787) | more than 3 years ago | (#34267052)

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:Ffs (2, Insightful)

LordLimecat (1103839) | more than 3 years ago | (#34267192)

Light isnt sped up going around black holes, though it is red-shifted.

Re:Ffs (3, Insightful)

DJRumpy (1345787) | more than 3 years ago | (#34268046)

It's all relative. Actually it is sped up, but not in the way you think. They've found that if a gravity well is strong enough, it actually pulls spacetime around it. If you were to shine a beam of light while based on spacetime that is moving, you in essence create a beam of light that is moving faster than the speed of light, at least for an observer standing on spacetime that is not moving.

Re:Ffs (0)

Anonymous Coward | more than 3 years ago | (#34267998)

I agree. It's a little bit like Virgin Galactic offering amusement rides in thin cardboard tubes and then all the Space Nutters going WE HAVE SPACESHIPS MARS COLONIES WEEKS AWAY!!!

Hiding things? Isn't that the point of invisible? (1)

Viol8 (599362) | more than 3 years ago | (#34266424)

Am I missing something or is it just more journalistic hyperbole? Hiding an event just means it can't be seen. I think we knew this much already.

Re:Hiding things? Isn't that the point of invisibl (0)

Anonymous Coward | more than 3 years ago | (#34266484)

I think we knew this much already.

maybe that knowledge was hidden in a space-time cloak?

Re:Hiding things? Isn't that the point of invisibl (2, Informative)

Jojoba86 (1496883) | more than 3 years ago | (#34266508)

Clicking through to the CNN article tells us:

"A safe cracker would be able, for a brief time, to enter a scene, open the safe, remove its contents, close the door and exit the scene, whilst the record of a surveillance camera apparently showed that the safe door was closed all the time,"

So it's a way of hiding something in time, without anyone really knowing anything is being hidden.

Re:Hiding things? Isn't that the point of invisibl (5, Funny)

Anonymous Coward | more than 3 years ago | (#34266524)

I thought a safe cracker was one without tuna.

Re:Hiding things? Isn't that the point of invisibl (1)

ginbot462 (626023) | more than 3 years ago | (#34268758)

I thought a safe cracker was one without tuna.

Or one without a case of Natty and a 10 gauge.

Re:Hiding things? Isn't that the point of invisibl (1)

ultranova (717540) | more than 3 years ago | (#34268616)

So it's a way of hiding something in time, without anyone really knowing anything is being hidden.

Based on the description, what it is is the equivalent of taking a picture of the safe, putting that in front of the camera, looting the safe and finally removing the picture.

How not to be seen . . . (2, Interesting)

PolygamousRanchKid (1290638) | more than 3 years ago | (#34266488)

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]

Better article (4, Informative)

ath1901 (1570281) | more than 3 years ago | (#34266516)

I found another article about the article which makes more sense: http://physicsworld.com/cws/article/news/44320 [physicsworld.com]

There is a chicken and car analogy that should appeal to the crowd here:

An analogy, says McCall, is a chicken crossing a busy road. Once the chicken steps onto the road cars must stop to let it pass, but as soon as it leaves the other side the cars would accelerate to catch up with the traffic ahead. To an observer farther down the road, the stream of passing cars would display no evidence of having slowed down.

So, there is no magical disappearing of time or events or 4D cloaking of spacetime. That's just bullshit from some journalist who doesn't understand what spacetime or 4D means... Not more than a recorded tv program is cloaking space time.

Re:Better article (-1, Offtopic)

cujaner (1942848) | more than 3 years ago | (#34266546)

I recently saw a report on intelligent driving systems, in which the auto refusal by a special sensor on the roadway detects and automatically brakes in front, I do think that it puts the future, the one is a source of error these can offset sensors. along the roads could be made much safer. http://www.erlebnis-check.de/blog [erlebnis-check.de]

Re:Better article (4, Informative)

ath1901 (1570281) | more than 3 years ago | (#34266594)

Ok, so here's my personal rant:
Why are all the non-linear optics experiments ALWAYS misinterpreted as having something to do with spacetime or relativity?

A optical black hole [wikipedia.org] is NOT a black hole. It's a piece of glass. Radiation from such an optical black hole is NOT Hawking radiation [slashdot.org] . It just happens to have the same explanation.

Just because light in a vacuum "happens" to travel at the fastest possible speed ("the speed of light" = c) doesn't mean that when light is slowed down, the maximum speed is somehow slowed down. Spacetime is completely unaffected by the bending/stretching/slowing down of light. You CAN travel faster than the speed of light in a piece of glass but you CAN NOT travel faster than the theoretical speed limit known as "the speed of light" / c.

Light isn't special. It is just another particle (photons). It doesn't affect spacetime in any way except by the gravitational force which happens to be tiny since it is so light (pun not intended).

Re:Better article (1, Interesting)

rtb61 (674572) | more than 3 years ago | (#34266710)

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 (3, Interesting)

XxtraLarGe (551297) | more than 3 years ago | (#34266844)

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 (2, Funny)

Anonymous Coward | more than 3 years ago | (#34266958)

Sup dawg, I heard you like to talk about time as a continuous function,
so I put a plank length in your spacetime, so you can quantize your time measurements

Re:Better article (3, Funny)

MadKeithV (102058) | more than 3 years ago | (#34266884)

Time is an illusion.
Lunchtime doubly so.

Re:Better article (0)

Anonymous Coward | more than 3 years ago | (#34267980)

Time is an illusion.
Lunchtime doubly so.

"By manipulating the way the light illuminating an event reaches the viewer, it is possible to hide the passage of time," said McCall, a creature so mind-bogglingly intelligent that he figured out how to arrange a towel such that if he can't see you, you really can't see him.

Re:Better article (-1, Troll)

Anonymous Coward | more than 3 years ago | (#34268258)

Time is an illusion.

Lunchtime doubly so.

Much like the illusion of your mom being attractive after imbibing on a coke and Jack Daniel's bender.

Re:Better article (0)

Anonymous Coward | more than 3 years ago | (#34266924)

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.

So why don't you always get first post then?

- or -

Look around you. You're WRONG. Q.E.D.

Re:Better article (2, Funny)

Anonymous Coward | more than 3 years ago | (#34266936)

500 BCE called, they want their arguments [wikipedia.org] back. ;)

Re:Better article (0)

Anonymous Coward | more than 3 years ago | (#34267414)

Kids these days... The meanings of all words have changed... Logic meant something entirely different in my time.

Re:Better article (1)

geekoid (135745) | more than 3 years ago | (#34269494)

That's only logical to the ignorant; just like the stupid idea that if you only wak half way over and over again you can never get to your goal.

There is a smallest piece of time and there is a smallest distance anything can move.

What next? that dumb ass question about the chicken and the egg?

Science has shot those, and most other, "philosophical" questions down.

Re:Better article (2, Insightful)

AstrumPreliator (708436) | more than 3 years ago | (#34267066)

Light isn't special. It is just another particle (photons). It doesn't affect spacetime in any way except by the gravitational force which happens to be tiny since it is so light (pun not intended).

A photon (most likely) does not have mass. Although, interestingly enough, it does have momentum. It is affected by gravity, such as passing by a star, because spacetime is curved and the photon is merely following a geodesic (generalized notion of a straight line through curved space)..

Re:Photon Mass (1)

reasterling (1942300) | more than 3 years ago | (#34267248)

Just curious, if photons did have even the most minuscule amount of mass could that mass possibly account for all the missing dark matter? I mean empty space is completely awash with photons. I know the logic that an object with mass can not travel at the speed of light. But photons have energy and e=mc^2 .

Re:Photon Mass (2, Insightful)

JustinOpinion (1246824) | more than 3 years ago | (#34268014)

Yes, in principle if photons had mass that could lead to something like dark matter.

However, in practice we know this isn't the case. First of all, if photons had mass (and quantum mechanics as we understand is roughly correct), this would modify a whole slew of predictions in all kinds of bizarre ways (down to fundamental things like the number of particles we observe and the stability of matter). Basically, the only way to match all our experimental data is with a massless photon.

Even beyond that, however, the measured distribution of dark matter (which we can infer based on things like galactic rotation, gravitational lensing, large-scale structure in the universe, etc.) does not match the measured distribution of photons (which we can calculate based on the positions of known light-emitters, like stars).

It's a neat idea, but appears not to be the case in our universe.

Re:Photon Mass (0)

Anonymous Coward | more than 3 years ago | (#34269342)

E=mc^2
v=hl
mass equivalent of photon=E/((hl)^2))
probably wrong somewhere, discuss

Re:Photon Mass (2, Interesting)

AstrumPreliator (708436) | more than 3 years ago | (#34268370)

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 (2, Interesting)

locofungus (179280) | more than 3 years ago | (#34268716)

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.

Re:Better article (1)

ath1901 (1570281) | more than 3 years ago | (#34270056)

Actually, a photon has zero rest mass. It has energy and to an observer it is a massive object since it bends spacetime just like any other massive object.

You could probably make up some kind of thought experiment about photons with energy mc^2 in a black box being indistinguishable from apples of mass m in a black box...

Re:Better article (1)

zpki (1942988) | more than 3 years ago | (#34268254)

Ok, so here's my personal rant: Why are all the non-linear optics experiments ALWAYS misinterpreted as having something to do with spacetime or relativity?

You have this one backwards. The theory is based on fully covariant (relativistic) EM; the fibre implementation (ie the nonlinear optics) is a suggested experiment that mimics many of the basic features of the spacetime (event) cloak concept.

Re:Better article (1)

geekoid (135745) | more than 3 years ago | (#34269436)

"the maximum speed is somehow slowed down."

Yes it is. The maximum speed of light within the environment is whatever light is moving at. There is no "Maximum speed of light" only "the Speed of light" which is the maximum any information can move.

"You CAN travel faster than the speed of light in a piece of glass"
Not within that material you can't. Sure, an object in a different environment may get 'around' the piece of glass faster, but thats a different thing. An observer inside the glass wouldn't never see you move faster then the light within the glass.

Re:Better article (3, Insightful)

locofungus (179280) | more than 3 years ago | (#34266696)

So, there is no magical disappearing of time or events or 4D cloaking of spacetime.

It's slightly more subtle than that. IIUC, it's impossible to detect something happening in the cloaked region of space. So in the chicken crossing the road scenario, to an outside observer, it looks like the cars travel at a constant speed and the chicken "magically" teleports from one side of the road to the other.

The idea that something is in one state or another without being able to detect intermediate states is not new to physics. If you attempt to "watch" the transition between two eigenstates you will always measure one state or the other. We can have a mathematical model of how the wave function evolves, we can do experiments that demonstrate that the wavefunction must have been in a state that our mathematical model describes as a superposition of eigenfunctions, but we can never measure that superposition.

In QM terms, I suppose the chicken would be described as "tunneling across the road"

(note that I have no reason to suppose there is any relationship between 4d cloaking and QM tunneling - it's merely an analogy that came to mind)

Tim.

Re:Better article (1)

Anne_Nonymous (313852) | more than 3 years ago | (#34267380)

So you're saying that the chicken crossed the road to keep from disrupting the space-time continuum and ending the universe as we know it?

Re:Better article (2, Funny)

ultranova (717540) | more than 3 years ago | (#34269470)

So you're saying that the chicken crossed the road to keep from disrupting the space-time continuum and ending the universe as we know it?

Well... Nobody's ever seen a chicken cross the road to prevent the apocalypse. I think that's evidence enough.

Re:Better article (1)

zpki (1942988) | more than 3 years ago | (#34268112)

I suggest reading the original paper. The theoretical machinery used is 4D and fully (spacetime) relativistic. If you can't cope with the physics literature, the press releases are more complete than the mangled stuff in the press (but the New Scientist isn't bad at all: http://www.newscientist.com/article/dn19727-how-to-cloak-a-crime-in-a-beam-of-light.html [newscientist.com] ) Press release (Imperial) : http://www3.imperial.ac.uk/newsandeventspggrp/imperialcollege/newssummary/news_16-11-2010-9-5-43 [imperial.ac.uk] Press Release (IoP): http://www.iop.org/news/nov10/page_45311.html [iop.org] . Regarding the chicken analogy, see http://www.qols.ph.ic.ac.uk/~kinsle/files/STcloak/ [ic.ac.uk]

Re:Better article (1)

Samantha Wright (1324923) | more than 3 years ago | (#34268560)

This sounds way better out of context.

I can see how an analogy might be compared to a chicken crossing a busy road, but is it really appropriate to say that analogies don't interrupt the flow of language to an observer?

My first thought was... (0)

Anonymous Coward | more than 3 years ago | (#34266648)

> My first thought was, a hypothetical space-time invisibility cloak?

Mine was, "Holy shit, it's cold out here. Put me back in!"

Filthy P'tagh! (1)

joshuaheretic (982785) | more than 3 years ago | (#34266706)

I understand why both researchers and journalists sometimes foster this kind of hype, and I'm sure this is an interesting quantum-scale optical effect. However, can we have a new rule that until they can make a Klingon Bird-of-prey invisible to the naked eye, they're not allowed to call it a cloaking device? Everybody remember where we parked!

Wasn't this an episode of Star Trek? (1)

digitaldc (879047) | more than 3 years ago | (#34266816)

You know the one where Kirk steals an invisibility cloak in order to hang out undetected in the women's shower room?

Re:Wasn't this an episode of Star Trek? (4, Funny)

uglyduckling (103926) | more than 3 years ago | (#34266910)

Ahhh! So you spotted that massive plot hole in the Harry Potter films too ;).

Re:Wasn't this an episode of Star Trek? (2, Insightful)

jellomizer (103300) | more than 3 years ago | (#34267024)

Why do you think after the second book they no longer care which house wins. Griffendorf keeps on getting a bunch of points taken away do to slipping accidents in the girls dorms.

Re:Wasn't this an episode of Star Trek? (0, Troll)

quatin (1589389) | more than 3 years ago | (#34267764)

I would like to make the request that we stop with the Harry Potter references. Can we not go through one legitimate discussion of this topic without mentioning that buffoon?

I don't insert "Hackers" movie quotes into articles about network security. You shouldn't trivialize actual science with little boys playing fairies. (Yes, it really is that annoying.)

Re:Wasn't this an episode of Star Trek? (0)

Anonymous Coward | more than 3 years ago | (#34268226)

You shouldn't trivialize actual science with little boys playing fairies. (Yes, it really is that annoying.)

Yeah...or you could just calm down and realise it's not that big a deal. Life's too short to be getting annoyed over trivial matters such as this.

Re:Wasn't this an episode of Star Trek? (0)

Anonymous Coward | more than 3 years ago | (#34268522)

Shouldn't have torrented the 30min version.

Re:Wasn't this an episode of Star Trek? (1)

geekoid (135745) | more than 3 years ago | (#34269574)

Kirk would only need an invisibility cloak to get into the womens restroom. Far to confident with the ladies for that. Picard on the other hand would... and possibly Janeway

Already happened (1)

Nidi62 (1525137) | more than 3 years ago | (#34267048)

Unfortunately it worked so well that it hid the entire inventing event, so no one noticed.

2012 Presidential Tag Line (1)

KingMotley (944240) | more than 3 years ago | (#34267138)

That could be a new 2012 presidential platform... "I have never inhaled marijuana outside a space-time invisibility cloak."

The Event (0)

Anonymous Coward | more than 3 years ago | (#34267152)

Hide The Event ? I'd say it was likely (given NBC's history) that the show would be canceled before it reaches the finale.

Anyway if these aliens (like Thomas) can control a space warp thing, why were they messing around in a craft that crashed in Alaska in 1944? You would think their technology was better than that.

Pay no attention to the man behind the curtain (0)

Anonymous Coward | more than 3 years ago | (#34267218)

I think I've seen this somewhere before. No, maybe not. Yes I did. Um, nope I didn't.

Will someone please disable my space-time cloak? Nothing is appearing to be what it seems.

You insen5itive 3lod? (-1, Flamebait)

Anonymous Coward | more than 3 years ago | (#34267244)

FrreBSD continues and some of the

Teleportation and Aging (0)

Anonymous Coward | more than 3 years ago | (#34267316)

Unfortunately, if this could ever be used to "teleport" you from one location to another, from your perspective you'd still have to make the journey it's just that time would stop in the outside world. Presumably you'd also still be limited by the speed of light and so would still have to put up with a long plane/spaceship ride to go long distances. Furthermore, because time does not stop for you, you would still age the same from your perspective. So if you make a 3 hr "cloaked" journey, to the outside world you would instantaneously transport but you would come out on the other side 3 hrs older than when you went in. Add this up over a lifetime of "teleporting" and you've shaved some time off your life from the perspective of the "outside" world.

Space-Time (1)

tom17 (659054) | more than 3 years ago | (#34267322)

Some interesting info on Space Time [youtube.com]

Sorry, it's been in my head since reading the article title, had to get it out there.

Came looking for another Dune reference (0)

Anonymous Coward | more than 3 years ago | (#34267480)

leaving disappointed.

Come on, nobody wanted to mention no-rooms and no-ships? Or am I more geekier than the normal /.er?

Ideas are cheap. (1)

TheSpoom (715771) | more than 3 years ago | (#34267976)

Implementation is hard. But everyone who has a "great" idea always seems to think the implementation will be easy. Go to it, scientists! We don't need to prove anything!

Look, an SEP field! (1, Funny)

Anonymous Coward | more than 3 years ago | (#34268018)

Look, an SEP field!

**FIRST POST!!! OMG!! YES! (1)

mrnick (108356) | more than 3 years ago | (#34268736)

**FIRST POST!!!

Yes! I knew it would happen eventually, thank goodness for my time cloak!!!

** Posting position may be affected by relative velocity, gravitational forces, temporal coordinate system and speed of light relative to observer and OP. Your mileage may vary!

How would they know it worked? (1)

mark-t (151149) | more than 3 years ago | (#34268804)

If an event were truly hidden from space time, wouldn't their observations of the effects of it also be hidden?

Sorry... maybe I've just seen too many time travel movies.

Red-shift (1)

tylerni7 (944579) | more than 3 years ago | (#34269164)

Correct me if I'm wrong, but this sort of invisibility cloak would not be perfect as described.

As light is initially slowed down to make "room" for the invisible event to take place, there is going to be a red-shift in the light because the waves must start arriving more slowly. While this change can be made subtle, that means that an "attacker" needs to either spend a long time slowing down the light, or the "attacker" would only create a small gap in time in which to work.

Still very cool though!
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