Nexus - 1805 - New Times Magazine-pages

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NEWSCIENCENEWSCIENCENEWSCIENCE Power from the Air: Device Captures Ambient Electromagnetic Energy to Drive Small Devices esearchers have discovered a way to capture and harness energy transmitted by such sources as radio and television transmitters, cellphone networks and satellite communications systems. By scavenging this ambient energy from the air around us, the technique could provide a new way to power networks of wireless sensors, microprocessors and communications chips. "There is a large amount of electromagnetic energy all around us, but nobody has been able to tap into it," said Professor Manos Tentzeris, of the Georgia Institute of Technology School of Electrical and Computer Engineering, who is leading the research. Free-Floating Planets May Be More Common Than Stars The team estimates that there are about twice as many free-floating Jupiter-mass planets as stars. In addition, these worlds are thought to be at least as common as planets that orbit stars. This adds up to hundreds of billions of lone planets in our Milky Way galaxy alone. The survey is not sensitive to planets smaller than Jupiter and Saturn, but theories suggest lower- mass planets like Earth should be ejected from their stars more often. As a result, they are thought to be more common than free-floating Jupiters. Previous observations spotted a handful of free-floating planet-like objects within star-forming clusters, with masses three times that of Arronemers have discovered a new class of Jupiter-sized planets floating alone in the dark of space, away from the light of a star. The team believes that these lone worlds are probably outcasts from developing planetary systems and, moreover, they could be twice as numerous as the stars themselves. "Although free-floating planets have been predicted, they finally have been detected," said Mario Perez, exoplanet program scientist at NASA Headquarters in Washington. "This has major implications for models of planetary formation and evolution." The discovery is based on a joint Japan—New Zealand survey that scanned the centre of the Milky Way galaxy during 2006 and 2007, revealing evidence for up to 10 free- floating planets roughly the mass of Jupiter. The isolated orbs, also known as orphan planets, are difficult to spot. The planets are located at an average approximate distance of 10,000 to 20,000 light years from Earth. outcasts Jupiter. But scientists suspect the gaseous bodies form more like stars than planets. These small, dim orbs, called brown dwarfs, grow from collapsing balls of gas and dust but lack the mass to ignite their nuclear fuel and shine with starlight. (Source: NASA Science News, 18 May 2on, http://inyurl.com/sulfqws) "We are using an ultra-wide-band antenna that lets us exploit a variety of signals in different frequency ranges, giving us greatly increased power-gathering capability.” Communications devices transmi energy in many different frequency ranges, or bands. The team's scavenging devices can capture this energy, convert it from AC to DC, and then store it in capacitors and batteries. The scavenging technology can take advantage o frequencies from FM radio to radar, a range spanning 100 megahertz (MHz to 15 gigahertz (GHz) or higher. Scavenging experiments utilising TV bands have already yielded power amounting to hundreds o microwatts, and multi-band systems are expected to generate one milliwatt or more. That amount o power is enough to operate many small electronic devices. By combining energy-scavenging technology with supercapacitors and cycled operation, the Georgia Tech team expects to power devices requiring above 50 milliwatts. (Source: ScienceDaily.com, 8 July 20, http://tinyurl.com/3ukj57t) This artist’s conception illustrates a Jupiter-like planet alone in the dark of space, floating freely without a parent star. (Image credit: NASA/JPL-Caltech) 50 * NEXUS AUGUST - SEPTEMBER 2011 www.nexusmagazine.com