This folks is
a simple proof of concept that can now be extended to forms of wave
production. More specifically, it
applies directly to applications using higher ordered cyclic functions that promise
to seriously tame gravity as we know and presently understand it.
We already
know from multiple UFO sightings that tractor beams are possible and certainly
desirable. Since a UFO also is using a
gravity control device in the form of a large ring band it makes perfect sense
that it may also be tapped to provide a tractor beam as well. Thus a proof of concept is important confirmation
of the apparent science.
And do not worry
about space. Gravity works just fine
there.
Tractor
beam
The device can move around
centimeter-sized objects.
By Douglas Main
Posted 05.09.2014 at 4:32 pm
This schematic shows how sound waves
normally pushed an object away, in (a) and (b). But if they are aimed at an
object as in (c), that is also appropriately shaped, the object can be pulled
toward the acoustic source.
APS/Alan Stonebraker
Tractor beams (short for "attractor
beams," which can bring one object closer to another from a
distance) are a common trope in science fiction. But could they be made in
real life? Researchers made news earlier this year when they created a
kind of tractor beam, or "optical
tweezers," that can move around nano-sized objects with light.
NASA scientists are also working on a project to reel
in objects with light; Australian researcher have moved small objects a
total of 5 feet with lasers. Most of this work has involved light,
but now, a separate group has made an acoustic tractor beam that can
move much larger objects with sound waves.
The device consists of about a thousand
ultrasound emitters, placed underwater. When turned on, scientists used it to
tug along centimeter-sized objects (roughly half and inch), such as a
small hollow triangular shape. Normally the effect of sending acoustic beams at
something would tend to push it away. But the scientists found that by
precisely controlling the angle of sound waves, they can create a low pressure
zone in front of the object, thus pulling it closer.
The technology has some limitations--it
couldn't be used in space, since as you probably know sound cannot travel in a
vacuum ("In space no one can hear you scream," as the Alien tagline
goes.) But it could possibly be used for some biomedical applications, perhaps
for manipulating objects beneath skin or within organs, without cutting.
"You can imagine medical diagnostics much like the tomato-freshness test,
squeezing cells to tell if they're cancerous or metastatic or normal,"
study co-author Gabriel Spalding, a physicist at Illinois Wesleyan
University, told
Popular Mechanics.
Acoustic
Tractor Beam
Phys. Rev. Lett. 112, 174302 –
Published 30 April 2014
ABSTRACT
Negative radiation forces act opposite to
the direction of propagation, or net momentum, of a beam but have previously
been challenging to definitively demonstrate. We report an experimental
acoustic tractor beam generated by an ultrasonic array operating on macroscopic
targets (>1 cm) to demonstrate the negative radiation forces and to map out
regimes over which they dominate, which we compare to simulations. The result
and the geometrically simple configuration show that the effect is due to
nonconservative forces, produced by redirection of a momentum flux from the
angled sides of a target and not by conservative forces from a potential energy
gradient. Use of a simple acoustic setup provides an easily understood
illustration of the negative radiation pressure concept for tractor beams and
demonstrates continuous attraction towards the source, against a net momentum
flux in the system.
DOI: http://dx.doi.org/10.1103/PhysRevLett.112.174302
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