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| SCIENCE & TECHNOLOGY |
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Not a bird or a plane,
it's a microdrone Prof Yash
Pal THIS UNIVERSE Ocean life on the brink of mass extinctions: study Black hole shreds star, sparking gamma ray flash Scientists develop new approach for cancer vaccine |
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Not a bird or a plane,
it's a microdrone The enemy might look up and ask if it's a bird, a plane or Superman. Soon, however, it might be a mechanical insect with flapping wings, transmitting sound and images back to commanders in the United States. And if it's not zipping through the air it could instead be perching quietly on a window sill near you. In recent years the US Army and Air Force have grown ever more dependent on unmanned aircraft, known as drones, to spy on and fire missiles at America's foes, and the Pentagon is now moving quickly to develop new generations of the machines, some of which will be as small as dragonflies. Research into new types of drones is moving at full tilt in a facility at Wright Patterson Air Force Base in Ohio, where the next big goal is the development of miniature drones that will use "flapping wing" technology to stay aloft and be able to land almost anywhere, hopefully undetected. Greg Parker, an aerospace engineer at the base, told The New York Times: "We're looking at how you hide in plain sight." Researchers say that while work has been done on replicating the mechanics of bird flight, the actions of an insect's wings are easier to copy and translate into moving parts. So intense is the focus on developing insect-like drones now that the warehouse where the research is being pursued has been called the "micro-aviary". One focus is developing drones that will have wings based on those of a hawk moth. "It's impressive what they can do compared to what our clumsy aircraft can do," said Major Michael Anderson, who is assigned to the base. Drone technology has become ever more crucial to US forces in arenas as far apart as North Korea (where they carry out surveillance of nuclear activities), Libya, Iraq and of course Afghanistan. While a decade ago the US had fewer than 50 unmanned aircraft ready for deployment, today it has as many as 7,000 of them. Best known to the general public is the Predator drone, which is about the size of a small propeller plane. It is flown remotely by pilots in front of computer screens with joysticks, usually in the US, who can both watch the enemy and fire upon it. Today, the US Air Force has more pilots training to fly drones than to fly manned aircraft. But there is a wide range of other drone models in service, including blimp-like machines that are tethered and provide stationary surveillance platforms, and tiny toy-like remote-control aircraft that can be pitched into the air like a ball by soldiers, moving forward to tell them what might be lurking around the next corner or over the next hill. Called Ravens, these are in use by US forces in Afghanistan. The Pentagon has asked Congress for $5bn to expand its drone fleet in the coming year. While insect drones are not yet off the drawing board, in February the US Air Force began testing a prototype hummingbird drone developed by AeroVironment, the private company which makes the Raven. Four inches long, it is said to be capable of hovering and flying forward at 11mph thanks to flapping wings.
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THIS UNIVERSE Is there any explanation as to why the human body is designed the way it is? Why do we have four fingers and a thumb on each hand and foot, why are all of them not of the same size and why do we have two eyes instead of one, etc.? We humans, like all other forms of life, are the result of a long line of evolution. It is appropriate for us humans to joy over the fact that we are so well endowed. This is true not only in respect of our physical equipment and capabilities but also many other gifts. The most important in my view is our capability to wonder and try to think and understand. Your questions, I believe, arise from these special faculties of us humans. Coming to your specific questions, we should be so utterly grateful for the way our hands are designed. With our hands we can hold a pen, we can thread a needle, and we can use a hammer or an axe. Also, we can play musical instruments, we can shake hands and, better than any other creature, we can clap vigorously when some one dances well, makes soul full music, or gives a stirring speech. Why do we have five fingers? I think we found some advantage, because we found that just so many fingers fold well within our palm to make a fist when needed. I do not know whether evolution itself decided that some time in distant future we would discover the decimal system, and ten fingers on two hands would a marvellous aid to help our children with simple arithmetic. Oh yes, I forgot to mention the advantage of having a thumb. Without a thumb, we would not have had any painting or art, or for that matter, any tennis or spin bowling. You would agree that they are all very necessary appendages for our body. You have also wondered about having two eyes. Could we not do with a single large eye? No, we could not. Our two eyes are separated by some distance. Each of them sees a slightly different view; both these are processed in our brain to form a single image in which we can also discern distance. With a single eye and just one image, we could not be. This gives an amazing advantage. I am so very grateful for being a specimen of a very special species. How does the moon acquire orange colour during an eclipse? Just think about the circumstance when a moon eclipse occurs. It is well known that the earth comes in between the sun and the moon so accurately that the moon goes into a deep shadow of the earth. But the earth does not include only the solid part of the earth which does not allow any light from sun to fall on the moon. It also includes the earth atmosphere which extends some distance further out. The sunlight going through this atmospheric envelope tangentially is heavily scattered and some of it, a very small amount nevertheless, does fall on that part of the moon that is completely shielded by the solid earth! The colour of this forward scattered light is predominantly towards the orange/red part of the spectrum, because the blue part of the light is strongly scattered away. This phenomenon is similar to that which gives us our blue sky during the day and an orange/red sun near sunset. In summary, the eclipsed moon does acquire an orange/red tinge because the sunlight scattered in the earth atmosphere in the forward direction illuminates the darkened moon during the eclipse. This effect is enhanced during periods when the atmosphere is a bit overloaded with volcanic ash. Readers wanting to ask Prof Yash Pal a question can e-mail him at palyash.pal@gmail.com
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Ocean life on the brink of mass extinctions: study Black hole shreds star, sparking gamma ray flash Scientists develop new approach for cancer vaccine
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