Sunday 23 January 2011

Johnald's Fantastical Daily Link Splurge

Johnald's Fantastical Daily Link Splurge

Video: Explorer Recounts Deepest-Ever Ocean Expedition

Posted: 21 Jan 2011 03:30 PM PST

Fifty-one years ago this Sunday, Swiss engineer Jacques Piccard and Navy oceanographer Don Walsh descended to the bottom of the Mariana Trench, seven miles below the sea's surface. It's the lowest point on Earth, and deeper than any human had gone before — or since.

Above is a new video chronicling the explorers' journey, weaving animation with audio from an interview granted by Piccard in 2005, three years before his death. The interview was conducted by New York writer Victor Ozols, but went unpublished and eventually ended up on his blog. There it was found by German design student Roman Wolter, who made the film.

"Piccard's story has been told in encyclopedic format before, but never before like this," wrote Ozols in an e-mail to Wired.com.

 

Piccard and Walsh performed their descent Jan. 23, 1960, inside the bathyscaphe Trieste — a closet-sized metal sphere joined to a giant gasoline-filled buoyancy tank, built with the assistance of Piccard's father. Since then, only two remotely operated robots have made the journey.

Video: Interview by Victor Ozols; video by Roman Wolter.

Image: Diagram of the Mariana Trench and its subduction-powered formation./Wikipedia/Vanessa Ezekowitz

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Quantum Entanglement Could Stretch Across Time

Posted: 21 Jan 2011 02:24 PM PST

In the weird world of quantum physics, two linked particles can share a single fate, even when they're miles apart.

Now, two physicists have mathematically described how this spooky effect, called entanglement, could also bind particles across time.

If their proposal can be tested, it could help process information in quantum computers and test physicists' basic understanding of the universe.

"You can send your quantum state into the future without traversing the middle time," said quantum physicist S. Jay Olson of Australia's University of Queensland, lead author of the new study.

In ordinary entanglement, two particles (usually electrons or photons) are so intimately bound that they share one quantum state — spin, momentum and a host of other variables — between them. One particle always "knows" what the other is doing. Make a measurement on one member of an entangled pair, and the other changes immediately.

Physicists have figured out how to use entanglement to encrypt messages in uncrackable codes and build ultrafast computers. Entanglement can also help transmit encyclopedias' worth of information from one place to another using only a few atoms, a protocol called quantum teleportation.

In a new paper posted on the physics preprint website arXiv.org, Olson and Queensland colleague Timothy Ralph perform the math to show how these same tricks can send quantum messages not only from place to place, but from the past to the future.

 

The equations involved defy simple mathematical explanation, but are intuitive: If it's impossible to describe one particle without including the other, this logically extends to time as well as space.

"If you use our timelike entanglement, you find that [a quantum message] moves in time, while skipping over the intermediate points," Olson said. "There really is no difference mathematically. Whatever you can do with ordinary entanglement, you should be able to do with timelike entanglement."

Olson explained them with a Star Trek analogy. In one episode, "beam me up" teleportation expert Scotty is stranded on a distant planet with limited air supply. To survive, Scotty freezes himself in the transporter, awaiting rescue. When the Enterprise arrives decades later, Scotty steps out of the machine without having aged a day.

"It's not time travel as you would ordinarily think of it, where it's like, poof! You're in the future," Olson said. "But you get to skip the intervening time."

According to quantum physicist Ivette Fuentes of the University of Nottingham, who saw Olson and Ralph present the work at a conference, it's "one of the most interesting results" published in the last year.

"It stimulated our imaginations," said Fuentes. "We know entanglement is a resource and we can do very interesting things with it, like quantum teleportation and quantum cryptography. We might be able to exploit this new entanglement to do interesting things."

One such interesting thing could involve storing information in black holes, said physicist Jorma Louko, also of the University of Nottingham.

"They show that you can use the vacuum, that no-particle state, to store a lot of information in just a couple of atoms, and recover that info from other atoms later on," Louko said. "The details of that have not been worked out, but I can foresee that the ideas that these authors use could be adapted to the black hole context."

Entanglement in time could also be used to investigate as-yet-untested fundamentals of particle physics. In the 1970s, physicist Bill Unruh predicted that, if a spaceship accelerates through the empty space of a vacuum, particles should appear to pop out of the void. Particles carry energy, so they would be, in effect, a warm bath. Wave a thermometer outside, and it would record a positive temperature.

Called the Unruh effect, this is a solid prediction of quantum field theory. It's never been observed, however, as a spaceship would have to accelerate at as-yet-unrealistic speeds to generate an effect large enough to be testable. But because timelike entanglement also involves particles emerging from vacuums, it could be used to conduct more convenient searches, relying on time rather than space.

Finding the Unruh effect would provide support for quantum field theory. But it might be even more exciting not to see the effect, Olson said.

"It would be more of a shocking result," Olson said. "If you didn't see it, something would be very wrong with our understanding."

Image: flickr/Darren Tunnicliff

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To Learn Best, Write an Essay

Posted: 21 Jan 2011 12:02 PM PST

Trying to remember what you've just studied, then writing it down, may be a surprisingly good way to learn.

In a study published January 21 in Science, researchers asked 200 college students to spend five minutes reading a short passage about a scientific subject. Afterwards, they were either told to re-read it several times, as if cramming for a test; make "concept maps" of the material; or spend 10 minutes writing a free-form essay about the passage.

One week later, the students were given short-answer tests on what they remembered, and asked to draw logical conclusions from those facts. Students who originally wrote essays performed best. Next came the crammers, then the concept mappers.

Students were then asked to draw concept maps from memory, and the essay-writers again did best, beating those students who made concept maps the first time around.

The findings are necessarily limited, but do suggest that retrieval practice, as the essay-writing was called, is a powerful learning tool. It may also be undervalued in progressive curricula that emphasize so-called elaborative methods, such as concept mapping.

However, concept mapping and cramming did prove useful in at least one way. Asked to self-assess their learning, students who used those methods reported higher levels of understanding than their essay-writing counterparts.

They didn't actually learn much, but they felt like it.

 

Images: 1) Renato Ganoza, Flickr. 2) Various types of test performance, broken down by study method. "Metacognitive predictions" means, what students felt they learned./Science.

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Citation: "Retrieval Practice Produces More Learning than Elaborative Studying with Concept Mapping." By Jeffrey D. Karpicke and Janell R. Blunt. Science, Vol. 331 No. 6015, January 21, 2011.

8 Beautiful Bioluminescent Creatures From the Sea

Posted: 21 Jan 2011 04:00 AM PST

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While a handful of land animals can create their own light, homemade luminescence is the rule rather than the exception in the open ocean's dark waters.

Researchers estimate that between 80 and 90 percent of deep-dwelling animals are bioluminous, creating light by mixing the pigment luciferin with luciferase, the enzyme that makes it glow. The light tends to green and blue, colors that travel far in seawater. Glowing helps attract mates, lure prey or confound predators.

Many of these animals live thousands of meters deep and are difficult for scientists to find and study. Here are some of the prettiest — and strangest — glowing creatures of the seas.

Above:

Clusterwink Snail

The clusterwink snail, recently described in the Proceedings of the Royal Society B, shines its light through a magnifying shell, making itself look more imposing.

Image: Nerida Wilson/University of California, San Diego.

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