DARPA’s Ultrasonic Cloaking Device
Sharon Weinberger looked the Pentagon’s 2008 budget request [PDF] and found something instantly recognizable to Star Trek fans: A cloaking device.
Unfortunately, it’s not quite up to 23rd Century Klingon standards:
This effort will use directed ultrasound technology to enable the capability to significantly reduce sound emissions from large scale tactical military hardware. Theory predicts that nonlinear effects of high-power acoustic radiation on the atmosphere can cause acoustic energy to dissipate rather than radiate. This theory has been confirmed in some limited experiments; this program will apply it to reducing acoustic emissions of U.S. equipment. Reduction in noise levels by at least 30dB would enable U.S. forces to effectively operate considerably closer to enemy forces without being detected aurally.
Not quite as cool as being totally invisible but this could certainly save a lot of lives.
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Active cancellation is one form of radar countermeasures. It’s very hard to do because you have to be able to detect incoming pulses and predict what the reflected signal looks like well enough to then generate a 180 degree out of phase analogous signal.
Similarly those metamaterials that allow light to pass around an object offer a cloak to light based detectors (like our eyes).
metamaterials
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But this isn’t trying to mimic the ambient noise, but rather dissipate the unwanted created noise. So they aren’t trying to create any specific wave form, just dampen the amplitude of all sound wave forms.
Can it work? Beats the foo out of me. My physics is sure not up to answer one way or the other. But then, that’s why they have the word “advanced” in DARPA’s name.
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Or take more lives, depending on which side of the aurally-cloaked equipment you are on.
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Or take more lives, depending on which side of the aurally-cloaked equipment you are on.
Roger that. But, then, I’m on our side. Much like Patton (or at least George C. Scott’s screenwriter), my preference is for the other poor bastard to give his life for his country.
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