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Invisibility cloak could hide mice from snakes
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Invisibility cloak could hide mice from snakes THE thermal rays of mice and men often go awry. An invisibility cloak built for a mouse could hide warm bodies from predators with thermal vision – and could scale up to hide humans from heat-seeking missiles. Invisibility cloaks, which harness the unusual properties of lightbending metamaterials, have shown theoretical promise for years. But
“The cloak was tested by hiding the toy’s lower body from the camera - its head seemed to float in the air”
Hers was a difficult story to unravel because by the time of her death she had interrelated mental and physical illnesses. It was not possible to determine if she took an overdose of morphine or if her heart simply stopped because of the many medications she was taking, on top of a physical weakness. But whatever the cause of death, her brother Kevin is angry that she spent the last half of her life cut off from her family and in great distress. “She was failed by people who were supposed to help her,” he says. “This shouldn’t be allowed to happen.” n
Fuse/getty
hysteria we last saw in the 1990s. “That’s the danger,” she says. Claims were made earlier this year, for instance, that Jimmy Savile, a British celebrity who undoubtedly assaulted many people over decades, was part of a satanic abuse circle. “That rings alarm bells for me,” says French. French is concerned that senior police officers have publicly stated that, above all else, victims will be believed in historic cases. One case was described as “credible and true” even before police investigated. “For a long time, victims weren’t listened to, but now the pendulum’s gone the other way,” he says. In the US, Loftus says allegations of historic abuse by the clergy are playing a similar role. Madeline Greenhalgh of the British False Memory Society, which helps subjects of false
outside of dramatic illusions made with lenses, these haven’t been cloaks that would fool your eye. To redirect the short wavelengths of visible light requires tiny structures, so instead early designs deflected longer wavelengths like microwaves. Cloaks have also struggled to handle many wavelengths of light at once. Now, a team at Zhejiang University in Hangzhou, China, has taken a –Just a fantasy?– significant step forward by making a cloak for infrared radiation, whose abuse claims, says she knows of wavelengths are only just too long to see. All animals – including humans – two families who believe their emit infrared as heat. Snakes can relatives’ fantasies have been sense this radiation even in darkness, triggered by news coverage using it to hunt down their prey. of historic abuse cases. “We want to simulate the scene of Carol Myers’ inquest catching a mouse,” says team member recorded an open verdict.
Hongsheng Chen. His team did that by getting a snake’s-eye view of a toy mouse heated to 35 °C through a thermal camera. They built an accordion-like structure from germanium, leaving a 2.7-centimetre-wide cavity in the middle for the toy mouse. The camera was placed on one side. The germanium sent infrared rays from behind the mouse on a curved path around the cavity, then bent them back into straight lines for the camera, making it seem like they had travelled through the structure. Rays emitted from inside the cavity were blocked. The team tested it by hiding the lower body of the toy mouse from the camera – its head seemed to float in the air. They also showed that the cloak could work as the environment around the toy varied between 30 °C and 45 °C (Advanced Optical Materials, doi.org/75c). “To my knowledge this is the first attempt to cloak against thermal radiation, and the authors introduce some novel design concepts that take forward the practical issues of designing a cloak,” says John Pendry of Imperial College London, who pioneered the mathematics behind invisibility cloaks. “With the basic theory done and dusted, cloaking is moving on to practical considerations.” Joshua Sokol n
–Now you see it...– 10 October 2015 | NewScientist | 9
Invisibility cloak could hide mice from snakes THE thermal rays of mice and men often go awry. An invisibility cloak built for a mouse could hide warm bodies from predators with thermal vision – and could scale up to hide humans from heat-seeking missiles. Invisibility cloaks, which harness the unusual properties of lightbending metamaterials, have shown theoretical promise for years. But
“The cloak was tested by hiding the toy’s lower body from the camera - its head seemed to float in the air”
Hers was a difficult story to unravel because by the time of her death she had interrelated mental and physical illnesses. It was not possible to determine if she took an overdose of morphine or if her heart simply stopped because of the many medications she was taking, on top of a physical weakness. But whatever the cause of death, her brother Kevin is angry that she spent the last half of her life cut off from her family and in great distress. “She was failed by people who were supposed to help her,” he says. “This shouldn’t be allowed to happen.” n
Fuse/getty
hysteria we last saw in the 1990s. “That’s the danger,” she says. Claims were made earlier this year, for instance, that Jimmy Savile, a British celebrity who undoubtedly assaulted many people over decades, was part of a satanic abuse circle. “That rings alarm bells for me,” says French. French is concerned that senior police officers have publicly stated that, above all else, victims will be believed in historic cases. One case was described as “credible and true” even before police investigated. “For a long time, victims weren’t listened to, but now the pendulum’s gone the other way,” he says. In the US, Loftus says allegations of historic abuse by the clergy are playing a similar role. Madeline Greenhalgh of the British False Memory Society, which helps subjects of false
outside of dramatic illusions made with lenses, these haven’t been cloaks that would fool your eye. To redirect the short wavelengths of visible light requires tiny structures, so instead early designs deflected longer wavelengths like microwaves. Cloaks have also struggled to handle many wavelengths of light at once. Now, a team at Zhejiang University in Hangzhou, China, has taken a –Just a fantasy?– significant step forward by making a cloak for infrared radiation, whose abuse claims, says she knows of wavelengths are only just too long to see. All animals – including humans – two families who believe their emit infrared as heat. Snakes can relatives’ fantasies have been sense this radiation even in darkness, triggered by news coverage using it to hunt down their prey. of historic abuse cases. “We want to simulate the scene of Carol Myers’ inquest catching a mouse,” says team member recorded an open verdict.
Hongsheng Chen. His team did that by getting a snake’s-eye view of a toy mouse heated to 35 °C through a thermal camera. They built an accordion-like structure from germanium, leaving a 2.7-centimetre-wide cavity in the middle for the toy mouse. The camera was placed on one side. The germanium sent infrared rays from behind the mouse on a curved path around the cavity, then bent them back into straight lines for the camera, making it seem like they had travelled through the structure. Rays emitted from inside the cavity were blocked. The team tested it by hiding the lower body of the toy mouse from the camera – its head seemed to float in the air. They also showed that the cloak could work as the environment around the toy varied between 30 °C and 45 °C (Advanced Optical Materials, doi.org/75c). “To my knowledge this is the first attempt to cloak against thermal radiation, and the authors introduce some novel design concepts that take forward the practical issues of designing a cloak,” says John Pendry of Imperial College London, who pioneered the mathematics behind invisibility cloaks. “With the basic theory done and dusted, cloaking is moving on to practical considerations.” Joshua Sokol n
–Now you see it...– 10 October 2015 | NewScientist | 9