|
|
Science
|
Written by Staff Writer
|
|
Oct 02, 2007 at 05:06 PM |
Invisibility has been on humanity's wish list at least since Amon-Ra, a diety who could disappear and reappear at will, joined the Egyptian pantheon in 2008 BC. With recent advances in optics and computing, however, this elusive goal is no longer purely imaginary. Last spring, Susumu Tachi, an engineering professor at the University of Tokyo, demonstrated a crude invisibility cloak. Through the clever application of some dirt-cheap technology, the Japanese inventor has brought personal invisibility a step closer to reality.
Tachi's cloak - a shiny raincoat that serves as a movie screen, showing imagery from a video camera positioned behind the wearer - is more gimmick than practical prototype. Nonetheless, from the right angle and under controlled circumstances, it does make a sort of ghost of the wearer. And, unlike traditional camouflage, it's most effective when either the wearer or the background is moving (but not both). You don't need a university lab to check it out: Stick a webcam on your back and hold your laptop in front of you, screen facing out. Your friends will see right through you. It's a great party trick.
Of course, such demonstrations aren't going to fool anyone for more than a fraction of a second. Where is Harry Potter's cloak, wrapped around the student wizard as he wanders the halls of Hogwarts undetected? What about James Bond's disappearing Aston-Martin in Die Another Day? The extraterrestrial camouflage suit in the 1987 movie Predator? Wonder Woman's see-through Atlantean jet? It's not difficult to imagine a better system than Tachi's. In fact, invisibility that would satisfy any wizard - not to mention any spy, thief, or soldier - is closer than you might think.
| 
|
|
|
Last Updated ( Oct 02, 2007 at 05:08 PM )
|
|
Read more...
|
|
|
Written by Staff Writer
|
|
Sep 25, 2007 at 02:22 PM |
The Bristlecone Pine (Pinus longaeva) was first identified as a long-lived tree by Dr Edmund Schulman following surveys in California's White Mountains in 1954. The oldest pines grow at elevations above 3,000 metres in arid, rocky areas of the Great Basin that covers the state of Nevada and parts of Utah and California. (This mountainous area of 500,000 square kilometres has no rivers or creeks flowing out of it.) They exist on the tree line in severe conditions, and often appear to be mostly dead, with only part of the trunk having living bark and leaves. This growth strategy is a response to damage from climate and lightning strikes, and allows the tree to exist on limited resources.
The bristlecones of Wheeler Peak in Nevada were believed to be older than those found in California. In 1964 a geology student called Donald R. Currey came to Wheeler Peak to study ice age glaciers, partly by collecting tree ring data. Using coring tools, he identified trees over 4,000 years old.
|
|
Read more...
|
|
|
Written by Staff Writer
|
|
Sep 07, 2007 at 07:29 PM |
Scientists claim to have broken the ultimate speed record - by making photons travel faster than light. Exceeding the speed of light, 186,000 miles per second, is supposed to be completely impossible.
According to Einstein's special theory of relativity, it would take an infinite amount of energy to accelerate an object through the light barrier. Travelling faster than light also turns back time with bizarre consequences.
An astronaut moving beyond light speed would theoretically arrive at his destination before leaving. But two German physicists now claim to have forced light to overcome its own speed limit using the strange phenomenon known as quantum tunnelling.
|  |
The research, published in the new Scientist magazine, involved an experiment in which microwave photons, energetic packets of light, appeared to travel "instantaneously" between two prisms forming the halves of a cube placed a metre apart.
When the prisms were placed together, photons fired at one edge passed straight through them, as expected....
|
|
Last Updated ( Sep 09, 2007 at 12:19 PM )
|
|
Read more...
|
|
|
Written by Staff Writer
|
|
Aug 22, 2007 at 12:00 AM |
Physicists in the US have developed a warm compaction technique to make small, powerful bulk permanent magnets. The exchange-spring magnets consist of two magnetic phases – both "soft" and "hard" – and have exchange coupling between them, which makes the magnets stronger than ordinary magnets containing just a single phase.
If perfected, the magnets could find use in a wide range of applications, from cell phones and data storage devices to hybrid cars, and could revolutionize our daily lives, say the researchers.
"Nanotechnology is not only good for creating novel materials like graphene but also for improving and re-birthing traditional materials like permanent magnets," team leader J Ping Liu of the University of Texas at Arlington told nanotechweb.org.
Indeed, theory predicts that the energy product, or (BH)max, (the figure of merit for a magnet's strength) for exchange-coupled nanocomposite magnets could reach 100 MGOe. This is double the current highest value for single-phase magnets.
A high (BH)max requires the material to have a large magnetization and a large coercivity – the magnetic field needed to reduce the magnetization of a ferromagnetic material to zero. Exchange-spring magnets contain a magnetically hard phase, which has a high coercivity, and a soft phase with low coercivity and high magnetization. These two phases interact by exchange coupling.
For the exchange coupling to be effective, however, the grain size of the hard and soft phases must be homogenously controlled at the nanoscale, which can be difficult using conventional top-down fabrication methods.
|
|
Last Updated ( Aug 29, 2007 at 10:31 AM )
|
|
Read more...
|
|
|
Written by Staff Writer
|
|
Aug 08, 2007 at 10:15 AM |
Iberian Lynx Lynx pardinus - The world's most endangered cat species, the Iberian lynx once thrived in Spain, Portugal and southern France. Today, its numbers have dwindled to some 120 individuals divided between small populations in Spain's Andalusia region. Habitat destruction, collisions with vehicles, poaching and a collapsing rabbit population have all contributed to the decline of this feline. As part of a conservation effort, the Spanish government has decided to release rabbits (the lynx's favorite cuisine) into the wild. If the Iberian lynx disappears, it will be the first feral cat species to go extinct in some 2,000 years.
|
|
Last Updated ( Aug 29, 2007 at 10:40 AM )
|
|
Read more...
|
|
| | << Start < Previous 1 2 3 4 5 6 Next > End >>
| | Results 19 - 27 of 46 |
|
Science
