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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."
I will post my reply using my spacetime browser but you won't see it until several nanoseconds later!
When the foot seeks the place of the head, the line is crossed. Know your place. Keep your place. Be a shoe.
I tried the same thing, but I must have broken one of my many mirrors...
mwahaha! if i'm never a part of events intersecting the light cone i dont exist!
oh shiii-
Ice Cream has no bones.
all fine until the spacetime moderators show up.
rewriting history since 2109
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.
Ooooo how do I get that type of mod points?
You are entitled to your own opinions, not your own facts.
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.
Indeed, things usually take a turn for the worse when a pissed of Jean Claude Van Damme comes knocking on your door.
I think we knew this much already.
maybe that knowledge was hidden in a space-time cloak?
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
Schroedinger's Brexit: The UK is both in and out of the EU at the same time!
"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.
I found another article about the article which makes more sense: http://physicsworld.com/cws/article/news/44320
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.
I thought a safe cracker was one without tuna.
The first thing I thought upon reading the headline, War of Omission. http://www.fantasticfiction.co.uk/o/kevin-odonnell-jr/war-of-omission.htm
There is no Kitsune in Kitsune Udon
I'll believe it when I don't see it!
> My first thought was, a hypothetical space-time invisibility cloak?
Mine was, "Holy shit, it's cold out here. Put me back in!"
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!
*applause*
_brilliant_
Seven Days with Ubuntu Unity
You know the one where Kirk steals an invisibility cloak in order to hang out undetected in the women's shower room?
He who knows best knows how little he knows. - Thomas Jefferson
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.
Noun/Adjective inversion win!
Unfortunately it worked so well that it hid the entire inventing event, so no one noticed.
The only thing necessary for evil to triumph is for it to be pitted against a slightly greater evil
let's pretend this never even happened
That could be a new 2012 presidential platform... "I have never inhaled marijuana outside a space-time invisibility cloak."
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.
Hmmm... This sounds familiar...
"Work is the curse of the drinking classes." -Oscar Wilde
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.
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 .
"For I desired mercy, and not sacrifice" -- God
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.
Some interesting info on Space Time
Sorry, it's been in my head since reading the article title, had to get it out there.
You have to get a post before the fr1st p0st!
WTF am I doing replying to an AC at 5 A.M on a Friday night?
leaving disappointed.
Come on, nobody wanted to mention no-rooms and no-ships? Or am I more geekier than the normal /.er?
If this becomes reality we will never hear about it ! (the first thing it would be used for is to hide the invention itself)
I always keep a ready supply of strippers and/or drugs for just such a situation.
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!
It's better to vote for what you want and not get it than to vote for what you don't want and get it.
- E. Debs
An anonymous reader writes
Anonymous.... OR INVISIBLE??!?!?
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.
Look, an SEP field!
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.
Would those be the Time Lords or the Auditors of Reality?
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.
Forget magic. Any technology distinguishable from divine power is insufficiently advanced.
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 (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.
God said, "div D = rho, div B = 0, curl E = -@B/@t, curl H = J + @D/@t," and there was light.
**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!
Encryption: I may not agree with what you say, but I will defend your right to encrypt it...
you have a theoretical time lock.
I am Bennett Haselton! I am Bennett Haselton!
I thought a safe cracker was one without tuna.
Or one without a case of Natty and a 10 gauge.
Atlas Shrugged : Thematic Story
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.
File under 'M' for 'Manic ranting'
Just tell the terminator that Jean Claude is Sarah Palin or whoever he was looking for.
I drank what? -- Socrates
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!
Jean-Claude Van Damme?
E=mc^2
v=hl
mass equivalent of photon=E/((hl)^2))
probably wrong somewhere, discuss
...Stays inside a spacetime invisibility cloak .
the Bureaucrats from Beyond.
rewriting history since 2109
I think I broke my space-time browser since I posted 5 or 6 times and nothing happened. Odd enough, firefox still works
The world is how you make it
Infinitesimally small IS NOT logically zero.
We might commonly round it down to zero for practical purposes, but it is not zero. Your argument falls flat on its face.
...over a couple of glasses of blood wine and a nice big bowl of gagh.
Light displays particle-wave duality. So it isn't really "just another particle." Though it may be "just another particle/wave," since other things also display this duality.
Looks like advanced civilizations throughout the universe have already perfected this technology. Dark matter, anyone?
If all the space, matter, and energy that was in the past is now in the present, and all the space, matter, and energy that will be in the future is now in the present would not that leave the past and the future completely void of everything? If there is nothing in the past or the future how can we say with any confidence that the past or the future actually exist? For that matter of space and time are inseparable and space was created at the big bang (just like every thing else) then space is locked into the same parameters of existence as mater and energy, it would only exist now which means that time ( which is inseparable with space ) must also only exist now. Shouldn't that mean that there is literally no such thing as the past or the future?
"For I desired mercy, and not sacrifice" -- God
Finally... the Chrono-legionnaire has arrived!
Reminds me of:
If a tree falls in a forest and no one is around to hear it, does it make a sound?
So, if I were within the space-time cloak, although I would exist, I would no longer exist in time, and for me time itself would not exist? That is, although I'd still be mass, I would no longer be an event in space-time; I would be a non-event mass with a quantum probability of zero?
Oh, say does that Star-Spangled Banner entwine / The myrtle of Venus with Bacchus's vine?
So it's a way of hiding something in time, without anyone really knowing anything is being hidden.
In my day we'd just loop the video feed. Kids today think they hafta be some kinda Neo to pull a heist.
First!
I actually posted this a while ago, but eh, you get the idea,,,
I don't know the meaning of the word 'don't' - J
really, it is. time is not altered. nothing travels through time (any more than it already does). the observer is distracted by the altered reflections of light.
something that does not exist in the physical world cannot be manipulated in the physical world. time only exists in the mind.