Science & Technology
Hiding objects inside a cloak that channels light around them to make it look as if they aren't there may soon be possible thanks to a breakthrough idea by materials scientists. It raises the prospect of invisibility shields that could hide objects sitting right under your nose.
© New Scientist
Objects are visible simply because light scatters off their surfaces and into your eyes. So in theory, a cloaking device could work by steering light around an object so that you see only the light from behind it, and not the object itself. Now John Pendry, a theoretical physicist at Imperial College London, and his colleagues have worked out how this could be done with a spherical cloak that channels light around an object hidden at its centre (see Diagram).
The stuff that makes this plausible is a new generation of "metamaterials", which can be tailored to have exotic electrical and magnetic properties not found in nature. The metamaterials developed so far consist of complex arrays of metal washer-like shapes and wires. The metal shapes are smaller than the wavelength of light and so interact with it, explains Pendry. "On these scales, it is not the chemical properties of the metal that determine how it interacts with light, it's the metal's structure."
The new idea is to build a sphere of metamaterial whose components are arranged in such a way that they bend radiation around the central cavity before sending it on its way, like a ring road diverting traffic around a town.
A 400-metre-long ice core recovered near the North Pole shows the region was subtropical about 55 million years ago.
Pasadena CA - The Cassini spacecraft captured this view of Saturn's largest moon, Titan (5,150 kilometers, or 3,200 miles across) looking out from slightly beneath the giant planet's ringplane.
TEHRAN, May 29 (Xinhua) -- An Iranian nuclear official said Monday that Tehran has conducted research into nuclear fusion, the state-run television reported.
"Iranian nuclear scientists are trying to catch up the advanced world in using nuclear energy through nuclear fusion," Sadat Hosseini, who runs the technical department at the Nuclear Research Center of Iran's Atomic Energy Organization, was quoted as saying.
In an engineering breakthrough that is still to be seen, scientists have unveiled a blueprint to make an invisibility cloak, like the one worn by author J.K. Rowling's boy wizard Harry Potter.
A team of British and American researchers outlined the materials they say would be needed to make such a cloak in Thursday's online issue of the journal Science.
The Pentagon's Defense Advanced Research Projects Agency, or DARPA, sponsored the research because of its potential military applications in the field of stealth technologies.
A cloak made of a "metamaterial" wouldn't reflect light or cast a shadow.
Voyager 2 could pass beyond the outermost layer of our solar system, called the "termination shock," sometime within the next year, NASA scientists announced at a media teleconference today.
The milestone, which comes about a year after Voyager 1's crossing, comes earlier than expected and suggests to scientists that the edge of the shock is about one billion miles closer to the Sun in the southern region of the solar system than in the north.
This implies that the heliosphere, a spherical bubble of charged low-energy particles created by our Sun's solar wind, is irregularly shaped, bulging in the northern hemisphere and pressed inward in the south.
Scientists with the National Aeronautics and Space Administration are flying over the shrinking Arctic ice cap this summer in an effort to determine just how much the melting ice is contributing to the rise of sea level worldwide.
THE title of Heinrich Päs's latest paper might not mean much to you. To those who know their theoretical physics, however, "Closed timelike curves in asymmetrically warped brane universes" contains a revelation. It suggests that time machines might be far more common than we ever thought possible.
Comment: Our Expert, Theoretical/Mathematical Physicist, Professor Arkadiusz Jadczyk tells us that this idea may have glimpses of truth, but it ignores the problems in the foundations of the quantum theory. Time loops are possible in many classical models, and there they lead to contradictions. Taking into account quantum theory may save us from these contradictions, but quantum theory is contradictory itself. So, we have one more hypothesis, but no real progress in our understanding how the universe works.
Making different sentences out of the same words was thought to be a unique feature of human language but scientists have now discovered syntax in monkeys.
A study of wild putty-nosed monkeys in Africa has found that they can mix different alarm calls to communicate new meanings to fellow members of a troop.
Scientists have reached a landmark point in one of the world's most important scientific projects by sequencing the last chromosome in the human genome, the so-called "book of life".
Chromosome 1 contains nearly twice as many genes as the average chromosome and makes up eight percent of the human genetic code.
It is packed with 3,141 genes and linked to 350 illnesses including cancer, Alzheimer's and Parkinson's disease.
Comment: Our Expert, Theoretical/Mathematical Physicist, Professor Arkadiusz Jadczyk tells us that this idea may have glimpses of truth, but it ignores the problems in the foundations of the quantum theory. Time loops are possible in many classical models, and there they lead to contradictions. Taking into account quantum theory may save us from these contradictions, but quantum theory is contradictory itself. So, we have one more hypothesis, but no real progress in our understanding how the universe works.