passion scientific

Friday, January 28, 2011

HOLOGRAPHIC PRINCESS LEIA NEARS REALITY

MIT's holograms are fast, but they have to trade quality for speed. Click to enlarge this image.
James D. Barabas/MIT

The Force is strong with holographic scientists these days. Researchers from MIT unveiled the fastest 3-D holographic video to date at a conference in San Francisco January 23, filming a graduate student dressed as Princess Leia and projecting her as a postcard-sized hologram in real time.

The holographic device plays a 3-inch projection at 15 frames per second, just shy of movie refresh rates of 24 to 30 frames per second, the MIT researchers demonstrated at the Society of Photo-Optical Instrumentation Engineers’ conference on practical holography.

The red hologram is jerkier and has much lower resolution than the one in Star Wars that sparked the public fascination with 3-D holograms in the 1970s. In fact, it kind of looks like a red blob on a staticky TV. But it’s 30 times faster than a telepresence device created in 2010 by University of Arizona researchers (SN Online: 12/4/10).

“I think it’s an important milestone because they were able to get to 15 frames per second, which is almost real time,” says physicist Nasser Peyghambarian, who led the Arizona research. “The quality is not as high, but hopefully it will get better in the future.”

The key to speed was computational power. The MIT team used a Kinect camera from an Xbox 360 gaming console to capture light from a moving object. Then they relayed the data over the Internet to a PC with three graphics processing units, or GPUs, tiny processors found in computers, cell phones, and video games that render video quickly. The processors compute how light waves interfere with each other to form patterns of light and dark fringes. Light bouncing off these fringe patterns reconstructs the original image. The MIT team used a display to illuminate the computer-generated fringes and create a hologram.

“The students were able to figure out how to generate holograms by using what GPU chips are good at,” says Michael Bove, an MIT engineer who led the research. “And they get faster every year. There’s room for a lot more understanding of how to compute holograms on them.”

MIT’s holograms are fast, says Peyghambarian, but they have to trade quality for speed.

Bove’s device uses one camera that estimates the depth of the object it is filming. The disadvantage of one camera, which is more consumer-friendly, is that you can’t see behind objects, says Bove. Also, even though graphics cards can compute high-resolution holograms, the effective display size is limited by a chip in the physical display to 150 millimeters by 75 millimeters, which Bove says is the biggest challenge to creating better holograms.

The Arizona device had a very different setup: Researchers grabbed video from 16 cameras angled around the object, so that one could walk around a holographic person and see not just the front side, but side profiles and back views. The team used an old-fashioned method that hologram artists have employed for decades, employing two lasers to create fringe patterns. Their key insight was engineering a special type of plastic that erases and rewrites quickly. The Arizona hologram is already high-definition and the size of a 17-inch TV, but speeding it up will require switching to a new laser system, says Peyghambarian.

“There’s a variety of technologies,” says Bove. “The fact is, the barrier to entry has been unbelievably high for the past 20 years. Now, many technologies are maturing at the same time. I think we’ll see some fun things in the next few years.”

Bove looks to the near future for consumer teleconferencing that connects people far, far away from each other, just like Darth Vader and the Emperor in their imperial chats. Star Wars purists will remember that Princess Leia’s plea was actually prerecorded.

Source:http://news.discovery.com/tech/hologram-princess-leia-3d-110127.html#mkcpgn=rssnws1

Tuesday, January 25, 2011

Can we feel the future through psi? Don't rule it out

A study suggesting the existence of precognition should be carefully scrutinised – not dismissed out of hand

- Ed Halliwell
- guardian.co.uk, Tuesday 25 January 2011 11.21 GMT
- Article history

A storm is hovering over the editors of the Journal of Personality and Social Psychology, which is to publish a paper offering evidence for precognition – knowledge of unpredictable future events. Feeling The Future, written by Daryl Bem, an emeritus professor of Cornell University, reports the results of nine experiments with more than 1,000 subjects, all but one of which appear to suggest paranormal powers. His findings are due to be published by the respected journal this year, and sceptics have been queueing up to rubbish them.

Among Bem's contentions is that participants given a memory test were more likely to remember words that they were later asked to practise, suggesting that the effects of this post-test rehearsal somehow reached back in time. He also found that subjects asked to select which of two curtains on a computer screen hid an erotic image were able to do so at a significantly greater rate than chance would predict. Intriguingly, the same experiment didn't produce any unusual results when the images behind the virtual curtain were less titillating.

The study is striking not so much for its data – anomalous results from smallish one-off experiments can hardly be described as earth-shattering – but for the fact that it comes from such a distinguished source (Bem is a highly acclaimed research psychologist), and because it has been accepted by such a prominent publication, following the usual peer review procedures. But perhaps even more interesting is the reaction it is producing among some critics – Ray Hyman, another emeritus psychology professor has described the publication as "pure craziness ... an embarrassment for the entire field", while Robert Park, a physicist at the University of Maryland called it "a waste of time ... it leads the public off into strange directions that will be unproductive".

The strength of such denunciations are curious. If Bem's experiments are indicative of ESP, then the implications are fascinating and wide-ranging, and at least worthy of continued investigation. Indeed, part of Bem's motivation, he says, was to construct easily replicable trial procedures so that interested parties could help build a reliable evidence base. If his trials are flawed, then they should be challenged robustly in the public domain.

Leaps in understanding require daring as well as rigour, and while extraordinary claims may require extraordinary evidence, there does seem to be sufficient data for ESP to at least merit an ongoing debate. Dean Radin's book The Noetic Universe offers reams of serious studies purporting to show phenomena such as perception at a distance, mind-matter interaction and telepathy – including meta-analyses of apparently well-conducted trials – that appear to add up to something interesting. Radin also suggests that theories underpinning psychic phenomena are no weirder – and indeed potentially compatible with – those regularly put forward and accepted in mainstream physics, or in mind-body medicine.

To the interested observer, the wide divergence of views among psi experts can be as befuddling as the evidence itself. When the people who have devoted their careers either to proposing or debunking the existence of the paranormal can't agree on the fundamentals of their field, even when presented with the same data, then what chance does the lay observer have? The arguments tend to stand or fall on the finer points of study design or statistical interpretation. One of the main critiques of Bem's study is not that his results are suspect, but that he has analysed them insufficiently, although it's worth noting that one of the sceptic re-analyses concludes that his data offers a "surprising degree of evidence" in favour of precognition.

But perhaps the most telling statistic in Bem's paper is that 34% of psychologists consider psychic phenomena to be impossible. Improbable, maybe. Unproven, perhaps. But impossible? That certainty seems to reflect a clinging to orthodoxy that is as much belief-based as the public's conviction that psychic powers are real and in our possession (apparently, 62% of us claim to know who's calling before we pick up the phone).

Daryl Bem's experiments may or may not give us evidence that precognition exists – but if publication of his paper can show that interest in psychic phenomena isn't limited to crackpot true believers, and that studies of it are worthy of more than blind dismissal or uncritical acceptance, then it will have more than served a purpose.

Wednesday, December 29, 2010

Backyard Astronomers Discover Black Holes and Other Wonders

Photo: VOA

Backyard astronomer Gus Johnson

Amateur astronomer Gus Johnson didn't set out to witness what scientists say is the first ever observed birth of a black hole. But that's just what he did in 1979. His discovery of Supernova 1979c was only the third supernova in another galaxy ever detected by an amateur. But it has become one of the most important and studied since. Amateur astronomers have been making discoveries for at least 400 years, dating to Galileo's spotting of Jupiter's moons. The hobby helps professional scientists every day.

Johnson likes the quiet and he likes the dark. But clouds and sub-zero temperatures are working against him as he stargazes near his home in Western Maryland.

"Well, Jupiter went behind a cloud so we have the moon," said Johnson.

Johnson has been stargazing for 50 years, and tonight he's invited some kids to join him. He has a near photographic memory of hundreds of star positions and he loves to share what he knows.

"That planet has a diameter 11 times that of the Earth," he said.

Johnson is the maintenance man at Deep Creek's Lake Nature Center. He's also an avid reader of Sky and Telescope magazine. In 1979, he was featured in the magazine - for discovering a supernova that scientists now believe is the newest and nearest black hole.

"When I came to M100 [galaxy] there was this little star that for some reason caught my attention," said Johnson. "I don't know why, and later on when I checked the photograph it was not on the photograph and that proved to be the the Supernova1979c."

Was he pretty proud?

"Yes I was," he replied. "And I am. And thankful too because so few people actually get to discover things."

Backyard astronomers have been making discoveries for centuries dating back to Galileo, whom amateurs claim as one of their own. His degree was in art. The famous Comet Hale-Bopp was discovered in 1995 by two amateurs, one of whom did not even own a telescope. He was using a friend's. And in 2007, volunteers in an online astronomy project discovered the "green pea" galaxies, so-named because they appear small and greenish in images.

Astrophysicist Kim Weaver was part of the NASA team that announced last month that Gus Johnson's supernova, or exploding star, was likely the birth of a black hole, a region in space where nothing can escape, not even light.

"We want to watch how this system evolves and changes in its youthful stages from when it's first born to when it grows into a child and a teenager," said Weaver.

Scientists believe that black holes are born often in the universe. But to actually see it happen, well that's a story.

When Johnson spotted the star more than 30 years ago, he put out an alert, and telescopes including NASA'S powerful Chandra X-Ray Observatory have been watching it ever since.

We caught up with Weaver at the Goddard Space Flight Center in Maryland where she works.

"This is what we think happens around a black hole, this ecreting material gets sucked into the orbit," she said.

She told us that while some astronomers dismiss the work of so-called citizen scientists, they do put thousands more eyes on the cosmos, which is a good thing.

"They don't have access to the large telescopes that professionals have access to but what they can do is they have the freedom to be able to use smaller telescopes any time they want to look all over the sky," said Weaver.

Professionals, Weaver says, tend to focus on smaller areas and on fainter objects further away. Another problem:

"Professional astronomers have created tons and tons of data," she said. "There are not enough professionals to look at all those data."

That's where backyard astronomers come in.

"So this is the first telescope I ever got. It's my favorite," said Caroline Moore. Moore has has an observatory in her backyard, with top of the line telescopes that she and her father use to track the ever-shifting heavens above New York State.

Two years ago, at age 14, she made a major discovery, not with a telescope but with a computer, scanning hundreds of photos as part of an online search team.

"I discovered the least luminous supernova ever to be observed, and I am the youngest person ever to discover a supernova so it kind of makes it a double interesting thing," she said.

Moore says supernova hunting is competitive.

"Maybe you will find there is some kind of thing on another planet that will help you cure cancer and we won't know that if we don't take even the smallest steps in journeying outside our planet a bit," she said.

Back in Maryland, Gus Johnson observes fresh-fallen snow and an iced-over Deep Creek Lake. There's something almost sad about his intense love of the environment, even with its fleeting nature.

But his discovery, that he holds onto.

Johnson wasn't looking for a supernova that night, it was entirely accidental. But, now he looks for them.

"It's kind of the grand realities of existence," said Johnson. "The Earth and everything we know is such a minute part of the universe. Watching the creation of God. That is pretty spectacular stuff."

Sunday, December 26, 2010

North magnetic pole racing toward Siberia?

The north magnetic pole (NMP), also known as the dip pole, is the point on Earth where the planet's magnetic field points straight down into the ground. Scottish explorer James Clark Ross first located the NMP in 1831 on the Boothia Peninsula in what is now northern Canada, and with the planting of a flag claimed it for Great Britain.

But the NMP drifts from year to year as geophysical processes within Earth change. For more than 150 years after Ross's measurement its movement was gradual, generally less than 15 kilometers per year. But then, in the 1990s, it picked up speed in a big way, bolting north–northwest into the Arctic Ocean at more than 55 kilometers per year. If it keeps going it could pass the geographic north pole in a decade or so and carry on toward Siberia. But why?

One compelling explanation appears in the December 21 Eos, the weekly transactions of the American Geophysical Union. In their Eos article (subscription required), and ina longer paper published earlier in 2010 in the Journal of Geophysical Research–Solid Earth, Arnaud Chulliat of the Institute of Earth Physics of Paris and his colleagues venture that a twisting molten plume beneath the Artic could be the cause:

According to some recent models, plumes of less dense fluid form at the inner core boundary and subsequently rise within [a cylinder] whose central axis is the Earth’s rotation axis. Such plumes undergo a strong helical motion due to the Earth’s rapid rotation, a phenomenon also observed in laboratory experiments with water. In the core, helical plumes advect and twist the magnetic field lines, forming what scientists call "polar magnetic upwellings."

Those upwellings, unloaded into the Arctic mantle, could produce intense patches of magnetic activity on the sort of decade-long timescales needed to explain the NMP's sudden acceleration. (The authors compare these patches to a kind of terrestrial version of sunspots.) And magnetic field measurements show dramatic shifts near the New Siberian Islands that seem to fit the bill.

"What happened under the New Siberian Islands at the core surface is that the rate of change of the magnetic field changed by a large amount during the 1990s," Chulliat says. That activity, he and his colleagues have found, could account for a large portion of the NMP's acceleration. But whether magnetic field changes under the New Siberian Islands and the speeding north magnetic pole ultimately arise from a twisted plume of fluid rising through the core remains unproved, Chulliat and his co-authors note. A resolution of the mystery will await better modeling, along with more data from satellites monitoring the Arctic's magnetic environment. The necessity of satellites, interestingly enough, is a consequence of the pole's recent movement—as the NMP drifts farther out to sea, it becomes harder and harder to reach the region with magnetometer-equipped aircraft. Compass Photo credit:http://schools.bcsd.com

Friday, December 17, 2010

Scientists find first evidence that many universes exist

The signatures of a bubble collision: A collision (top left) induces a temperature modulation in the CMB temperature map (top right). The “blob” associated with the collision is identified by a large needlet response (bottom left), and the presence of an edge is determined by a large response from the edge detection algorithm (bottom right). Image credit: Feeney, et al.

By looking far out into space and observing what’s going on there, scientists have been led to theorize that it all started with a Big Bang, immediately followed by a brief period of super-accelerated expansion called inflation. Perhaps this was the beginning of everything, but lately a few scientists have been wondering if something could have come before that, setting up the initial conditions for the birth of our universe.

In the most recent study on pre-Big Bang science posted at arXiv.org, a team of researchers from the UK, Canada, and the US, Stephen M. Feeney, et al, have revealed that they have discovered four statistically unlikely circular patterns in the cosmic microwave background (CMB). The researchers think that these marks could be “bruises” that our universe has incurred from being bumped four times by other universes. If they turn out to be correct, it would be the first evidence that universes other than ours do exist.

The idea that there are many other universes out there is not new, asscientists have previously suggested that we live in a “multiverse” consisting of an infinite number of universes. The multiverse concept stems from the idea of eternal inflation, in which the inflationary period that our universe went through right after the Big Bang was just one of many inflationary periods that different parts of space were and are still undergoing. When one part of space undergoes one of these dramatic growth spurts, it balloons into its own universe with its own physical properties. As its name suggests, eternal inflation occurs an infinite number of times, creating an infinite number of universes, resulting in the multiverse.

These infinite universes are sometimes called bubble universes even though they are irregular-shaped, not round. The bubble universes can move around and occasionally collide with other bubble universes. As Feeney, et al., explain in their paper, these collisions produce inhomogeneities in the inner-bubble cosmology, which could appear in the CMB. The scientists developed an algorithm to search for bubble collisions in the CMB with specific properties, which led them to find the four circular patterns.

Still, the scientists acknowledge that it is rather easy to find a variety of statistically unlikely properties in a large dataset like the CMB. The researchers emphasize that more work is needed to confirm this claim, which could come in short time from the Planck satellite, which has a resolution three times better than that of WMAP (where the current data comes from), as well as an order of magnitude greater sensitivity. Nevertheless, they hope that the search for bubble collisions could provide some insight into the history of our universe, whether or not the collisions turn out to be real.

“The conclusive non-detection of a bubble collision can be used to place stringent limits on theories giving rise to eternal inflation; however, if a bubble collision is verified by future data, then we will gain an insight not only into our own universe but a multiverse beyond,” the researchers write in their study.

This is the second study in the past month that has used CMB data to search for what could have occurred before the Big Bang. In the first study, Roger Penrose and Vahe Gurzadyan found concentric circles with lower-than-average temperature variation in the CMB, which could be evidence for a cyclic cosmology in which Big Bangs occur over and over.

More information: Stephen M. Feeney, Matthew C. Johnson, Daniel J. Mortlock, and Hiranya V. Peiris. "First Observational Tests of Eternal Inflation." arXiv:1012.1995v1 [astro-ph.CO]

via: The Physics arXiv Blog

GSLV rocket now taller, heavier

India's geosynchronous satellite launch vehicle (GSLV), scheduled to blast off on Monday with an advanced communication satellite (GSAT-5P), is now taller by two metres and heavier by four tonnes as compared to its standard configuration. The Indian Space Research Organisation's standard configuration for the GSLV rocket is a height of 49 metres and 414 tonnes in weight at lift-off.

The rocket that would lift off Monday stands 51 metres tall and weighs 418 tonnes.

PS Veeraraghavan, director of the Vikram Sarabhai Space Centre, told IANS: "This time the fuel quantity for the cryogenic engine has increased and its thrust power has also gone up. The rocket will be carrying a heavier satellite (GSAT-5P) weighing 2,310 kg."

The Russian made cryogenic engine will be powered with 15.2 tonnes of fuel (liquid hydrogen as fuel and liquid oxygen as oxidizer), an increase of around three tonnes, and the engine's length has also increased.

The rocket has a bigger heat shield - four-metres in diameter and made of fibre reinforced plastic (FRP) - as compared to the standard configuration of 3.4-metre diameter made of aluminium alloy metal.

With the changes in rocket's configuration, necessary calibrations have been carried out in the rocket's navigational systems, control dynamics and aerodynamics so that the flight is smooth and the mission is successful, a source associated with ISRO told IANS.

Over the years, the carrying capacity of the GSLV has also increased -- from 1,530 kg in 2001 for GSAT-1 to 2,220 kg for GSAT-4 in April 2010.

The latest has a payload of 2,310 kg with 36 transponders -- an automatic receiver and transmitter of communication or broadcast signals. Successful launch of the satellite will take the agency's transponder capacity to around 235 from 200 in orbit now.