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14 March
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03.09.06
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NASA's Cassini spacecraft may have found evidence of liquid water reservoirs that erupt in Yellowstone-like geysers on Saturn's moon Enceladus. The rare occurrence of liquid water so near the surface raises many new questions about the mysterious moon.
Image right: Plumes of icy material extend above the southern polar region of Saturn’s moon Enceladus as imaged by the Cassini spacecraft in February 2005. The monochrome view is presented along with a color-coded version on the right. The latter reveals a fainter and much more extended plume component. + Full caption
"We realize that this is a radical conclusion -- that we may have evidence for liquid water within a body so small and so cold," said Dr. Carolyn Porco, Cassini imaging team leader at Space Science Institute, Boulder, Colo. "However, if we are right, we have significantly broadened the diversity of solar system environments where we might possibly have conditions suitable for living organisms."
High-resolution Cassini images show icy jets and towering plumes ejecting large quantities of particles at high speed. Scientists examined several models to explain the process. They ruled out the idea that the particles are produced by or blown off the moon's surface by vapor created when warm water ice converts to a gas. Instead, scientists have found evidence for a much more exciting possibility -- the jets might be erupting from near-surface pockets of liquid water above 0 degrees Celsius (32 degrees Fahrenheit), like cold versions of the Old Faithful geyser in Yellowstone.
Mission scientists report these and other Enceladus findings in this week's issue of Science.
"We previously knew of at most three places where active volcanism exists: Jupiter's moon Io, Earth, and possibly Neptune's moon Triton. Cassini changed all that, making Enceladus the latest member of this very exclusive club, and one of the most exciting places in the solar system," said Dr. John Spencer, Cassini scientist, Southwest Research Institute, Boulder, Colo.
"Other moons in the solar system have liquid-water oceans covered by kilometers of icy crust," said Dr. Andrew Ingersoll, imaging team member and atmospheric scientist at the California Institute of Technology, Pasadena, Calif. "What's different here is that pockets of liquid water may be no more than tens of meters below the surface."
Other unexplained oddities now make sense. "As Cassini approached Saturn, we discovered that the Saturnian system is filled with oxygen atoms. At the time we had no idea where the oxygen was coming from," said Dr. Candy Hansen, Cassini scientist at NASA's Jet Propulsion Laboratory in Pasadena. "Now we know that Enceladus is spewing out water molecules, which break down into oxygen and hydrogen."
Scientists are also seeing variability at Enceladus. "Even when Cassini is not flying close to Enceladus, we can detect that the plume's activity has been changing through its varying effects on the soup of electrically-charged particles that flow past the moon," said Dr. Geraint H. Jones, Cassini scientist, magnetospheric imaging instrument, Max Planck Institute for Solar System Research, Katlenburg-Lindau, Germany.
Scientists still have many questions. Why is Enceladus currently so active? Are other sites on Enceladus active? Might this activity have been continuous enough over the moon's history for life to have had a chance to take hold in the moon's interior?
"Our search for liquid water has taken a new turn. The type of evidence for liquid water on Enceladus is very different from what we've seen at Jupiter's moon Europa. On Europa the evidence from surface geological features points to an internal ocean. On Enceladus the evidence is direct observation of water vapor venting from sources close to the surface," said Dr. Peter Thomas, Cassini imaging scientist, Cornell University, Ithaca, N.Y.
In the spring of 2008, scientists will get another chance to look at Enceladus when Cassini flies within 350 kilometers (approximately 220 miles), but much work remains after Cassini's four-year prime mission is over.
"There's no question that, along with the moon Titan, Enceladus should be a very high priority for us. Saturn has given us two exciting worlds to explore," said Dr. Jonathan Lunine, Cassini interdisciplinary scientist, University of Arizona, Tucson, Ariz.
The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL, a division of the Caltech, manages the mission for NASA's Science Mission Directorate. The Cassini orbiter was designed, developed and assembled at JPL.
For images and more information, visit: http://www.nasa.gov/cassini and http://saturn.jpl.nasa.gov . | 1 June Toyota Motor Corp. aims to start selling robots that can help look after elderly people or serve tea to guests by 2010, the Asahi daily reported on Tuesday. Japan's top automaker sees a declining birthrate and aging population leading to growing demand for robots that can help in tasks such as child care and nursing care, the report said. Toyota will soon set up a liaison committee to develop technology for the robots with group firms, including car parts maker Denso Corp. it added. Toyota Motor's music-playing robots capture center stage with their performance during the opening ceremony for the Toyota group pavilion at the 2005 World Exposition in Nagoya, central Japan March 10, 2005. Toyota Motor Corp. aims to start selling robots that can help look after elderly people or serve tea to guests by 2010, the Asahi daily reported on May 31 2005. Japan's top automaker sees a declining birthrate and aging population leading to growing demand for robots that can help in tasks such as child care and nursing care, the report said. 26 December TIME MAGAZINE, JUNE 4, 2001, VOL.157 NO.22
Brain Power In the brave new world of technology, we may soon be able to control distant objects just by thought By JAMES GEARY
Wil McIntyre for TIME. Nicolelis trained monkeys to move this robotic arm via vrain waves.
Yuri Geller claims he can bend spoons simply by using his brain. In the South Korean city of Taejon, people are learning a very similar trick—though they need a computer between themselves and the cutlery. Here's how the experimental software works. You don an electrode-studded cap that monitors brain waves and sends data to a computer that displays a virtual spoon. Different types of mental activity produce distinct signals in the brain, and the computer can discern, in a crude way, what's going on inside your head. To make the spoon bend, you have to relax. When the computer detects signals from a calm brain, the spoon begins to wilt.
What's going on in Taejon, at the Korea Research Institute, is a very basic example of what could be the most interactive technology of the future: brain-computer interfaces. Early computers were controlled by cardboard punch cards; the first PCs demanded typed DOS commands; the mouse gave us a graphic interface. Will we one day be able to enter the world of computing with no external mechanical intermediary whatsoever—in other words, just by thinking? Researchers around the globe are working on the problem. The Joint Research Centre of the European Commission, for example, has developed the Adaptive Brain Interface, a helmet and software program (like the one in Korea) intended to allow disabled people to operate appliances using thought commands. At the British government's Defense Evaluation and Research Agency, in Farnborough, the same techniques are helping fighter pilots fly jets with their minds. But the place where brains and computers are truly coming together is in the lab of Miguel Nicolelis, associate professor of neurobiology at the Duke University Medical Center in North Carolina. He has trained two owl monkeys to control a robotic arm via brain signals—giving glimpses of how the virtual and physical worlds may merge.
Working with colleagues at Duke, M.I.T.'s Laboratory for Human and Machine Haptics (also known as the Touch Lab) and the State University of New York Health Science Center, Nicolelis implanted electrodes into the sections of the monkeys' brains in which the planning and execution of arm movements takes place. When the brain instructs the body to make a motion, it fires off electric signals well before any action actually takes place; in other words, the body lags slightly behind the brain's intention to act. In effect, the brain warms up for an impending movement by directing specific clusters of neurons to fire, just as you might warm up your car's engine by pumping the gas pedal.
Nicolelis and his colleagues monitored the monkeys' brain signals as they warmed up for various tasks, like reaching for food, and isolated the signals that preceded the movements. Then they routed the monkeys' brain signals through a computer. As a monkey started to grasp for food, the computer picked up the neural traffic and forwarded it to a robotic arm called the Phantom. When the monkey extended its arm, the Phantom, using the neural signals from the monkey, precisely mimicked the action. Nicolelis even transmitted the brain signals over the Internet to the Touch Lab in Cambridge, Massachusetts, so the monkey's neural commands operated another Phantom 965 km away.
Nicolelis is convinced that this system will work for humans—an interface that might allow paralyzed people, who generally have healthy limbs that they are unable to use due to spinal cord damage (which prevents brain signals from reaching their limbs), to control their own biological limbs. It could also give people extended senses, allowing them to have virtual limbs in cyberspace or robotic limbs in the physical world. "The brain knows that it has an arm and a hand because it is connected to these things and gets feedback from them," Nicolelis says. "The same could be true for robotic or virtual appendages. If you control a remote hand that senses objects and sends tactile sensations back to your brain, it behaves as if it's your own hand. It becomes part of you. Your body becomes extended beyond the surface of your skin."
What Nicolelis is describing is a reverse phantom limb. Instead of continuing to feel the presence of a limb that is no longer there, people equipped with a brain-computer interface could operate new appendages, and the brain would eventually come to regard these as its own. But what could a person do with a remote robotic or virtual limb? The possibilities range from the mundane to the otherworldly. In the virtual realm, these appendages would dispense with the bulky technology of conventional haptics and allow Web shoppers to squeeze a peach online to see if it's ripe. Video conferences and chats might start with actual handshakes. And of course, there's sex. Consenting adults could use the technology to engage in far more intimate embraces and manipulations. In the realm of robotics, devices could be sent to dangerous or inhospitable climes, like deep-sea thermal vents or the craters of active volcanos.
For the human brain to truly incorporate prosthetics into its body map requires feedback: the brain will only become aware of its new limbs if they make their presence known. To see how the monkeys might respond to this kind of anatomical extension, Nicolelis is creating a feedback loop between the monkeys and the robotic arm. In the next experiments the monkeys will have sensors attached to their bodies, so that the robotic arm delivers tactile sensations directly to their skin. When the monkey's brain waves impel the robotic arm to grasp a piece of fruit, for example, the animal will be able to feel the fruit's texture. The monkeys will also be able to watch the robotic arm in action on a computer screen. This kind of tactile and visual feedback, Nicolelis hopes, will teach the monkeys to associate the arm's movements with their thoughts. Once they make that link, they might not take the trouble to stretch out their arms anymore. Why bother when a mere thought will move the robot arm?
So far, there is no way to tap into the brain without dramatically invasive surgery, so human experimentation is unlikely. And there's an intriguing risk in the realm of brain-computer interfaces. What would happen if the process was reversed? The signals that are routed from the monkey's brain through the computer to control the robotic arm could be sent back to the monkey—to control its behavior. Implants in humans would face strong opposition unless the possibility of this kind of mind control could be eliminated, which so far seems impossible to achieve.
Nicolelis is confident that a technological breakthrough will come, perhaps in the form of some kind of permanent intracranial implants, and that the ethical issues surrounding the technology will be resolved. It will probably be a long time before our brains will merge with our computers. When that day does come, however, our bodies will still be ourselves—but they could well have more than just two arms and two legs.
© James Geary 2001. This is an edited excerpt from Geary's book The Body Electric, which will be published by Weidenfeld & Nicolson in the fall
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