Fatal Flaw Discovered In Invisibility Cloaks 255
KentuckyFC writes "Carpet cloaks took the world by storm last year because they were the first devices to hide objects at optical frequencies. The idea is that a thin layer of dielectric material placed on a surface can make light look as if it is reflecting off the original surface. In other words, the layer is invisible and anything embedded within it is invisible too. This trick is like hiding something under a carpet, hence the name. Carpet cloaks are relatively easy to make because the dielectric material does not need to be specially constructed to steer light in special ways; physicists call this an isotropic material. Now a group at MIT has shown that isotropic carpet cloaks have a fatal flaw. When viewed at an angle, the carpets don't hide objects at all. Instead, they simply shift their position by about the same distance as they are high. So when viewed from an angle of 45 degrees, an object 0.2 units high is shifted to one side by a distance of 0.15 units, says the team. That's a serious limitation for carpet cloaks."
bummer (Score:2, Insightful)
The fatal flaw is: (Score:2, Insightful)
They DON'T WORK!
Re:The fatal flaw is: (Score:5, Funny)
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so, do you believe it now that you can kinda see it from an angle?
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Kirk, "now everyone knows why Kligons looked a scant shifty."
Re:The fatal flaw is: (Score:5, Insightful)
I can't see how they could work.
This is only about 'carpet cloaks', not invisibility cloaks in general. The problem is that a carpet cloak is the optical analogue of simply putting a display screen in front of the object and a video camera behind the object. In other words, of course it doesn't bloody work from the side, you morons. A general invisibility cloak is still possible, but may require phased array optics or other exotic active techniques.
Re:The fatal flaw is: (Score:5, Funny)
No, the fatal flaw is that a cloaked object moving at warp speed emits a slight subspace variance. Adversaries performing an antiproton scan may also be a problem.
Re:The fatal flaw is: (Score:5, Funny)
What if we modify the phase variance?
Re:The fatal flaw is: (Score:5, Funny)
What if we modify the phase variance?
yeah, as long as we randomly modulate the shield frequencies, reverse the polarity of the heisenberg compensators, and amplify the transporter buffers... we should be good to go. Earl Grey tea never tasted so good.
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Don't forget to note, and share with others, the differences between self-sealing stem bolts and warp matrix flux capacitors.
Re:The fatal flaw is: (Score:5, Funny)
This solution will never work.
No one has even suggested routing extra power to the main deflector array yet.
Reverse the polarity? (Score:5, Funny)
What if we modify the phase variance?
yeah, as long as we randomly modulate the shield frequencies, reverse the polarity of the heisenberg compensators, and amplify the transporter buffers... we should be good to go. Earl Grey tea never tasted so good.
Now see here... If the polarity of anything is to be reversed, then clearly we should start with the neutron flow...
Re:The fatal flaw is: (Score:4, Funny)
No, no, no. You need to narrow the angular confinement beam.
Re:The fatal flaw is: (Score:5, Informative)
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As far as anyone's sensors were concerned, that'd light you up like a Christmas tree.
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I thought the problem was the expulsion of highly-charged particles? Plasma, or whatever it's called. After all, the thing's gotta have a tailpipe.
Re:bummer (Score:5, Funny)
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They did. Then they switched it on, and ever since they are seeking the device.
Re:bummer (Score:5, Funny)
Unfortunately, every member of the search team is slacking off, assuming someone else is looking for it.
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They did. Then they switched it on, and ever since they are seeking the device.
You gave me a great idea: use the invisibility cloak to take a nap at work! As long as you're nowhere someone's likely to trip over you and don't snore too loudly you'd have it made!
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Still, it's better than a fatal flaw that causes users to spontaneously combust.
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At least that would have been funny!
Cheer up (Score:5, Informative)
Well, cheer up. It might still mean that the Romulan's weapons hit some nearby console when they think they're targeting the warp core. Of course, it would be better if they didn't hit anything at all, but I'm affraid that the law that for each hit a console must explode in a shower of sparks and send some ensign flying across the room is more immutable than the laws of refraction ;)
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Wrong Cloak (Score:5, Insightful)
So what they're saying is it's more of a Cloak of Displacement? While less stealthy, I think that's actually better odds of avoiding the hit than the penalty for attacking an invisible opponent.
Re:Wrong Cloak (Score:5, Funny)
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Better a D&D reference than another of the endless Harry Potter ones...
I haven't seen a single Harry Potter reference so far. It's been all Star Trek.
I guess people just figure everyone already knows about the various workarounds like the Marauder's Map and so on...
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He appears to be referencing an hirsute ceramicist of some variety.
I guess? (Score:4, Insightful)
Yeah - you aren't invisible, but wouldn't that still make the tracking missile miss you?
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If it's optically tracked, sure. You might be out of luck if the operator is using IR.
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No, it's not. Not unless the warhead is nuclear.
A near miss against sufficient armor is a miss. That's half the reason the armor is there in the first place.
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No, it's not. Not unless the warhead is nuclear.
You probably meant "No, it's not. Not if the warhead is nuclear." Read the post. I said "almost". This cloak would be nearly completely effective against bullets. Nukes would not be.
Man I get tired of you children.
Re:I guess? (Score:5, Informative)
You mean in real life, as opposed to internet dick waving arguments? That depends.
Depends on the size and type of warhead, the geology of the ground, the angle of the impact of the missile and the alignment of the tank relative to the strike.
A "standard" 1000lbs conventional cruise missile warhead is a fragmentation/blast effect weapon. Against a 60-ton MBT, anything more than a couple meters away will have minimal effects on the crew, assuming they're buttoned up. Shaken and dinged up, maybe.
OTOH, the tank itself may have been damaged and/or lost mobility but it's a far cry from having what's essentially a 1000 lbs land directly on the vehicle, in which case the tank is most assuredly dead and the crew does not survive.
In terms of the very basic science, what about the explosion is the dangerous bit? Fragmentation and the pressure wave, plus possible secondary fragmentation if you're inside a vehicle. Tank armor is designed to protect against these threats, which is why hardware designed to kill tanks are specialized to either penetrate armor or strike where there is next to no armor (the top).
Directly ON the tank, game's over. Next to the tank, now you're playing against the tank's strength, which is why I responded to badboy_2002 and interval1066 the way I did. A tank sittng right next to where the cruise missile hit is decidedly NOT about the same thing as a direct hit.
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No, it's really not. Anti-tank weapons usually require a direct hit for a kill, or a very near hit to do significant disabling damage.
For example,
- smaller anti-tank missiles like the US Javelin or Soviet RPG use shaped charges (HEAT) that need to have virtually direct hits for the superheated metal core to penetrate armor.
- air to surface missiles like the AGM-65 Maverick use kinetic energy to penetrate the target before exploding.
- the Hellfire and various other popular TOW system
Re:I guess? (Score:5, Interesting)
Depends on the size of the missile...
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I think you'll find it's less about the size of the missile and more about the yield of the warhead.
One of the advantages to 10+ Mton nuclear warheads, is that you don't need to be very precise
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No, it's about the size of the missile. The warhead is always listed in pounds but the potential is always listed in kinetic energy.
For example, the BrahMos has 32 times the kinetic energy of the Tomahawk, despite having a warhead 3/5 the size. It is by far much more destructive than our Tomahawk because of its higher mass and higher velocity capability.
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Maybe so but a broad spray of shrapnel and bullets won't. Even rain could defeat a cloak unless the rain goes right through it without resistence.
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Two words. Splash. Damage.
That's four words.
Or were you saying that "Two words" is two words? Seems like a bit of a tautology, though maybe not for the reason you'd think...
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Not if it realizes you're likely behind a cloak and just adjusts itself with some nifty math.
But ... that was my first thought as well.
Okay, so I'm not invisible, but you still don't actually know where I'm at so its close enough for a lot of neat things.
I suspect however, that much like in the fantasy of StarTrek (sorry to burst some of your bubbles :) and root kit detection, theres always a way to detect the target, but knowing the right way to look for it is half the battle.
In general, Stealth aircraft j
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I assumed this applied to most of the Electromagnetic spectrum, or is it just visible light, do they say? I always naturally assume IR included in these kinds of things, since it is so close to visible light on the spectrum.
Radar on the other hand, I thought we had reliable countermeasures for, like jamming? or have I been watching too much Hollywood
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That depends. If the cloaks only affect visible light: No, the tracking missile would not miss you. Most missile guidance systems are still based on RADAR or IR, which do not use visible light.
I'm willing to take my chances that Natalie Portman does not have tracking missiles in her bedroom.
I would also assume that what you'd be hiding is so small as to render an invisibility cloak redundant.
Military Applications (Score:5, Interesting)
I'm sure a carpet cloak like this would have military applications, and in a desert environment like the Middle East, people aren't going to notice you unless they're close to you.
A sniper on a ridge covered with one of these babies is still going to do the job.
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So if I understand this right TFA says that these cloaks just render something as appearing where it isn't rather than completely invisible when viewed from various angles?
If so that's still got the possibility of being pretty bloody useful.
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At least it could hide things from satelites, since they don't look down at any significant angle.
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I'm sure a carpet cloak like this would have military applications
Sure, if you have soldiers the size of a pinhead.
But then, remember that all the jihadists have to do is move sideways a bit and "ha ha, we can see your pinhead, you silly infidel !"
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Unless the enemy sniper fails at shooting and randomly hit you =)
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While slashnerds may not be able to throw on a cloak of invisibility and slide into the womens locker room
Not to worry - we're working on autonomous robot spiders to place cameras for us...
Soo.... (Score:4, Insightful)
Re:Soo.... (Score:5, Insightful)
They're making things invisible. It's kind of hard. So cut them a break? It's not like it's been done before and they just half-assed it after all.
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Well, they probably did and really knew about it for a long time, but geeks being geeks, these minor details probably didn't come out because they were so proud of what they had accomplished, and rightfully so. Even a cloak that works head on is freaking impressive to the point of becoming magic. I know they are just wave guides, but its still freaking impressive.
With that in mind, someone comes a long and notices it a long time later and points it out and the scientists are like 'yea well, we haven't got
Finally!!! (Score:4, Funny)
I see no sig... (Score:2, Funny)
I'm sorry, my "Disable sigs" preference has completely cloaked your sig.
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Adjust your viewing angle
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Try looking at your monitor sideways!
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Worth a shot, right?
Fatal Flaw Discovered In Invisibility Cloaks (Score:3, Funny)
You could bump into the invisible object.
Props to Soulskill (Score:3, Insightful)
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Wow, given the implied Scottish accent in "you-cannae-fire-while-cloaked", I actually would have thought that was a reference to Scotty from Star Trek.
Apparently, I'd have been wrong. Of course, one can argue that any Scottish accent in Sci Fi after Scotty is, by definition, an homage to the great engineer -- and, for purposes of discussion, I bel
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There were Wing Commander books? I'm only familiar with the Wing Commander video games that were the basis for the movie.
Pictures (Score:4, Informative)
Re:Pictures (Score:4, Funny)
In the meantime, here's a close-up photo of a black hole [ubermorgen.com].
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In the meantime, here's a close-up photo of a black hole [ubermorgen.com].
I found your link enlightening.
invisiball (Score:2)
but will the cloaks still work when shaped like small* spheres?
*small where you are almost looking radial from any direction
What happens... (Score:2, Interesting)
Shoot to miss (Score:4, Interesting)
So when viewed from an angle of 45 degrees, an object 0.2 units high is shifted to one side by a distance of 0.15 units, says the team. That's a serious limitation for carpet cloaks.
Maybe. But it would be a great way for soldiers to conceal themselves from aimed rifle fire.
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That might work. A 6 ft soldier would appear to be displaced by about 4.5', if that ratio holds.
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Say I have a cube covered by this thing. When looking at it from a 45 degree angle, I see the cube displaced.
So what if I then take another slightly-larger carpet cloak and prop it up 45 degrees off-axis such that when I look at this outer cloak straight-on, I see "through" the outer cloak, and when I look at it at 45 degrees, I see
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Couldn't they just use two cloaks placed at the appropriate angles in relation to each other?
Oh, well.... (Score:2)
Disappointing (Score:4, Interesting)
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If you look at the invisibility cloak the wrong way, it kills you!
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> If you look at the invisibility cloak the wrong way, it kills you!
Those are Soviet invisibility cloaks.
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As in "In Soviet Russia, invisibility cloaks look through you... after blasting a hole in you?"
They're right! (Score:2)
So you're saying... (Score:2, Insightful)
It took a team from MIT to walk to the side of the object, look at the object and report that the object could be seen? I think this cloak managed to hide something other than the object....
0.2 units high by 0.15 units? (Score:4, Insightful)
I mean, I know we all understand it, but if you're giving an example, why use unitless decimals when you can use integers and tangible concepts? Why not just say it would displace a 4 meter tall truck by 3 meters instead of 0.2 units tall object by 0.15 units?
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ever since they discoverd this theoretical flaw (Score:3, Funny)
in a theoretical device, i have been theoretically impressed
The Fatal Flaw (Score:2)
two obvious solutions (Score:2)
1. Roll up the carpet.
2. Put the object in a carpet, then put the carpeted object in another, slightly angled carpet, then put THAT into yet another slightly more angled carpet, and that entire batch into still yet another, even more slightly angled carpet, etc, until all angles are covered.
Invisibility Disadvantage (Score:2)
Remember the "Wonder Woman - Invisible Man - Superman Encounter"?
I'll pass on the cloak in any event, thanks.
I'm suspicious... (Score:2)
For all the talk of cloaking technologies I hear around here, this is the first I've heard of this one. Sure, I'm not an expert in the field, but if this "took the world by storm" last year, I'm surprised no news stories ever reached me.
Most suspicious, though, are the references to this as a technology for which practical devices have been built. The effect described in TFA is something you could see empirically if you had a working model; you don't need someone to draw a diagram showing the course of a
There must be lots (Score:2)
simple solution (Score:2)
rotating mirror mount?
FIRST POST!!!1 (Score:2)
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When viewed from an angle, your first post has a fatal flaw.
Thermals... (Score:2)
... wouldn't these "invisibility cloaks" be easily defeated with thermal detection equipment?
Displacement is still fatal. (Score:2)
The displacement isn't as useful as everyone thinks. Anything that is wider than it is tall will still get hit by any shot that's near center or to the correct side of the displacement, and some shots that would have missed will be hits. Actually anything whose height to width ratio is 4:3 or lower will still get hit. That covers a lot of the military equipment you'd want to hide - tanks, planes, ships, most buildings, most vehicles, anyone not standing up, etc.
Re:All over the world (Score:4, Insightful)
From TFA:
Zhang and co go on to prove their assertion by tracing a ray that passes through the kind of isotropic carpet cloak that Pendry suggested. What they've discovered will shock carpet cloakers all over the world.
Yeah, all over the world.... uhm, all three of them. (Emphasis mine)
The three that YOU CAN SEE...
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You can't see this post, oh wait, maybe you can...
Yes, I can, but 1.5 posts below where it actually is.
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I don't think anyone has ever thought or suspected that the 'invisibility cloaks' of today are in any way without flaws.
I don't know. I mean, I haven't seen them, so clearly they're working...