Science & Technology


Real-life tractor beam pulls in particles

The Millennium Falcon
© Fair Use, Screengrab/Lucas Film
The Millennium Falcon in Star Wars Episode IV: A New Hope.
The invisible force that pulls in the Millennium Falcon spacecraft to the Death Star in Star Wars movies is still far from becoming a reality, but physicists have developed a miniature version of sorts: a tractor beam that can reel in tiny particles.

The laser-based retractor beam pulled the particles a distance of about 8 inches (20 centimeters), which is 100 times farther than any previous experiments with tractor beams.

"Because lasers retain their beam quality for such long distances, this could work over meters," study researcher Vladlen Shvedov, research fellow at the Australian National University, said in a statement. "Our lab just was not big enough to show it."

During the experiment, the researchers used a laser that projected a doughnut-shaped beam of light with a hot outer ring and cool center. They used the light beam to suck in tiny glass spheres, each of which measured about 0.2 millimeters (0.008 inches) wide.

Not only did the researchers move the glass spheres farther than had been demonstrated in previous experiments, but they used a different technique altogether. Other retractor beams rely on the momentum of light particles in the laser beam to reel in mass. In those experiments, the momentum from the light particles shooting out of the laser is transferred to the target that the laser is hauling in. However, that technique works well only in a vacuum that is shielded from other free-floating particles that can interfere with the momentum transfer.

Electrostatic force microscopy (EFM) shows electric charge propagating along microbial nanowires

© Credit: UMass Amherst
UMass Amherst researchers recently provided stronger evidence than ever before to support their claim that the microbe Geobacter produces tiny electrical wires, called microbial nanowires, along which electric charges propagate just as they do in carbon nanotubes, a highly conductive man-made material.
The claim by microbiologist Derek Lovley and colleagues at the University of Massachusetts Amherst that the microbe Geobacter produces tiny electrical wires, called microbial nanowires, has been mired in controversy for a decade, but the researchers say a new collaborative study provides stronger evidence than ever to support their claims.

UMass Amherst physicists working with Lovley and colleagues report in the current issue of Nature Nanotechnology that they've used a new imaging technique, electrostatic force microscopy (EFM), to resolve the biological debate with evidence from physics, showing that electric charges do indeed propagate along microbial nanowires just as they do in carbon nanotubes, a highly conductive man-made material.

Physicists Nikhil Malvankar and Sibel Ebru Yalcin, with physics professor Mark Tuominen, confirmed the discovery using EFM, a technique that can show how electrons move through materials. "When we injected electrons at one spot in the microbial nanowires, the whole filament lit up as the electrons propagated through the nanowire," says Malvankar.

Yalcin, now at Pacific Northwest National Lab, adds, "This is the same response that you would see in a carbon nanotube or other highly conductive synthetic nanofilaments. Even the charge densities are comparable. This is the first time that EFM has been applied to biological proteins. It offers many new opportunities in biology."

Comment: see also: Forming new circuits - Meet the electric life forms that live on pure energy


Ten years on, scientists still debating the origins of Homo floresiensis - the 'Hobbit'

Homo floresiensis
© John Gurche/National Museum of Natural History
Homo floresiensis adult female - model of head.
It's been ten years since the bones of Homo floresiensis, aka, the "hobbit" were uncovered in Liang Bua, a cave, on the island of Flores in Indonesia, and scientists still can't agree on the diminutive hominin's origins.

This month, the journal Nature has printed a comment piece by Chris Stringer of the Natural History Museum in London and two pieces by Ewen Callaway, one a retrospective with interviews with the central players, and the other a podcast with the four principle scientists involved in the find - Bert Roberts, Thomas Sutikna, Dean Falk, and Stringer.

Did H. floresiensis descend from Australopithecus, leaving Africa and somehow settling on Flores, or was it a case of an early member of our family tree finding its way to the island and then because of limited resources, evolving into a much smaller size? That's the central question in the debate.

The majority opinion has sided with the island effect, mostly because of the time frame - H. floresiensis existed a mere 13,000 years ago, which means it was alive when other Homo sapiens were about, thus it seemed to make sense that H. floresiensis was also a member that had become stranded on an island. But Stringer doesn't agree. In his commentary piece he notes the chin and jaw are more reminiscent of pre-human fossils, dating back approximately two million years.

Also, the body shape and tiny brain appear to be more primitive than humans. He says taken together, the evidence suggests a closer match with Australopithecus, a pre-human group living in Africa which also includes the remains of the famous "Lucy" - and which also date back to approximately 1.2 million years ago.

Sun unleashes massive X-class solar flare

solar flare
The Sun has fired off a massive X-Class solar flare which astronomers are suggesting could be the start of a huge increase in solar activity.

NASA's Solar Dynamic Observatory captured the X-class flare -- the most powerful there is -- erupting from a massive Active Region on the star's surface.

Since the solar flare the sun spot has apparently doubled in size and is now around 78,000 miles wide -- that's almost as wide as Jupiter.

Comment: One wonders if there is a correlation between this massive solar flare and recent fireball activity over Brazil (twice), Alabama, the Netherlands, Iowa, and probably Northwestern Louisiana too; and the recent close shave of Comet Siding Spring with one of our planetary neighbours, Mars?

To understand more about the Electric Universe theory, Plasma discharge modes, our Sun's companion and it's accompanying cometary swarm, and much more, read Earth Changes and the Human-Cosmic Connection.

For more relevant information, listen to:

SOTT Talk Radio show #70: Earth changes in an electric universe: Is climate change really man-made?

SOTT Talk Radio: The Electric Universe - An interview with Wallace Thornhill


"Missing" disaster led to all-time worst extinction

There were thought to be five mass extinctions in Earth history. Fossil evidence is now pointing to a sixth - and it's not the human-made Anthropocene

© New Scientist
Could five big extinctions become six... or seven?
They always get you when you're down. Life's biggest-ever disaster - the "great dying" 252 million years ago - was helped by another mass extinction just 8 million years before that.

If confirmed, it would mean that life in the Permian period was hit by a double whammy that made the extinction of the dinosaurs look like a tea party. This newly discovered second Permian extinction could have left ecosystems fatally vulnerable to the final knockout punch.

The great dying put paid to more than 90 per cent of all marine species as well as 70 per cent of land animals. It is widely considered the most comprehensive extinction event of all time, and the only one that caused mass extinction of insects. It marked the end of the Palaeozoic era, which had run for 288 million years, and seen the evolution of the first marine animals with hard shells, and the first land plants and animals.

Trilobites (bottom right of picture), which had thrived for 270 million years, were wiped out. Reptiles like the sail-backed dimetrodon and the massive dinocephalians disappeared, replaced by the reptile ancestors of dinosaurs, birds, pterosaurs, crocodiles - and mammals.

The perfume of the comet

How does a comet smell? Since early August, the Rosetta Orbiter Sensor for Ion and Neutral Analysis (ROSINA) is sniffing the fumes of the comet Churyumov-Gerasimenko with its two mass spectrometers. The detected chemistry in the coma of the comet is surprisingly rich already at more than 400 million kilometers from the Sun.

© ESA/Rosetta/NAVCAM
Image taken on 26 September from a distance of 26.3 km from Comet "Chury." The image shows the spectacular region of activity at the « neck » of the comet with ices sublimating and gases escaping from inside the comet.
The perfume of this comet is quite strong, with the odour of rotten eggs (hydrogen sulphide), of horse stable (ammonia) and the pungent, suffocating odour of formaldehyde. This is mixed with the faint, bitter, almond-like aroma of hydrogen cyanide. Add some whiff of alcohol (methanol) to this mixture paired with the vinegar like aroma of sulphur dioxide and a hint of the sweet aromatic scent of carbon disulphide and you arrive at the perfume of our comet.

While this doesn't probably make a very attractive perfume, remember that the density of these molecules is still very low and that the main part of the coma is made up of sparkling water (water and carbon dioxide molecules) mixed with carbon monoxide. "This all makes a scientifically enormously interesting mixture in order to study the origin of our solar system material, the formation of our Earth and the origin of life," says Kathrin Altwegg from the Center of Space and Habitability (CSH) of the University of Bern. "And after all: it seems like comet Churyumov was indeed attracted by comet Gerasimenko to form Churyumov-Gerasimenko, even though its perfume may not be Chanel No 5, but comets clearly have their own preferences"

Florida lizards evolve rapidly, within 15 years and 20 generations

© Yoel Stuart/U. of Texas at Austin
The left hind foot of the green anole after evolution. Toe pad measurements were taken on the expanded scales at the end of the longest toe.
Scientists working on islands in Florida have documented the rapid evolution of a native lizard species -- in as little as 15 years -- as a result of pressure from an invading lizard species, introduced from Cuba.

After contact with the invasive species, the native lizards began perching higher in trees, and, generation after generation, their feet evolved to become better at gripping the thinner, smoother branches found higher up.

The change occurred at an astonishing pace: Within a few months, native lizards had begun shifting to higher perches, and over the course of 15 years and 20 generations, their toe pads had become larger, with more sticky scales on their feet.

"We did predict that we'd see a change, but the degree and quickness with which they evolved was surprising," said Yoel Stuart, a postdoctoral researcher in the Department of Integrative Biology at The University of Texas at Austin and lead author of the study appearing in the Oct. 24 edition of the journal Science.

North America to experience spectacular sunset due to partial solar eclipse October 23

solar eclipse
© Reuters / Abdel-Halim Shahaby
Much of North America will experience a solar eclipse on Thursday, with the moon covering up to 70 percent of the sun in the late afternoon. Along most of the East Coast and Midwest, the event will occur during sunset, allowing for dramatic photography.

"Sunsets are always pretty. One sunset this month could be out of this world. On Thursday, Oct. 23rd, the setting sun across eastern parts of the USA will be red, beautiful and... crescent-shaped," NASA Science wrote. The alignment of the two orbs on the East Coast at the end of the day "will be especially beautiful... transforming the usual sunset into something weird and wonderful."

The farther north viewers are, the deeper the eclipse they'll see, and the farther west they are, the higher the sun and moon will be in the sky. Thus the comparatively later dusk of the Midwest may provide the most spectacular views of sunset-enhanced phenomenon.

"Observers in the Central Time zone have the best view because the eclipse is in its maximum phase at sunset," longtime NASA eclipse expert Fred Espenak said. "They will see a fiery crescent sinking below the horizon, dimmed to human visibility by low-hanging clouds and mist."

New study suggests 21-day Ebola quarantine is off-base, virus could incubate longer

Hospital workers and public health officials in the U.S. have come under fire for a series of missteps in their response to the Ebola crisis, from initially misdiagnosing Thomas Eric Duncan to allowing a nurse who cared for him at a Dallas hospital to fly on a commercial airliner shortly before she too was diagnosed with the deadly illness.

Now an engineering professor with expertise in assessing the risks posed by pathogens claims he's identified another big problem with authorities' response to the crisis.

In a paper published Oct. 14 in the journal PLOS Currents: Outbreaks, Drexel University's Dr. Charles N. Haas argues that there's not enough evidence to support the recommended 21-day quarantine period for people suspected of harboring the virus.

Genomic remnants from ancient viruses play a prominent role in embryonic development

ancient viruses
© Credit: A*STAR Genome Institute of Singapore
Genomic remnants from ancient viruses may help human embryonic stem cells maintain the flexibility needed to form the full spectrum of tissues in the body.
Like fossils buried beneath a modern landscape, the human genome is littered with sequences that originated from ancient viral DNA insertion events. Scientists have long assumed that these 'transposable elements' are, like fossils, biologically inactive and primarily interesting as a window into evolutionary history. However, researchers at the A*STAR Genome Institute of Singapore have now uncovered evidence that some of these sequences play a prominent role in early embryonic development.

Huck-Hui Ng and colleagues embarked on this project in collaboration with Guillaume Bourque at Canada's McGill University. Bourque's group had discovered that one particular class of sequences of transposable elements - known as human endogenous retrovirus subfamily H (HERV-H) - appears to be specifically expressed in human embryonic stem cells (hESCs). Indeed, these HERV-H sequences are actively transcribed in hESCs, producing enigmatic RNA strands that do not encode a protein but nevertheless appear to serve some function.

Ng and Bourque set out to clarify the role of this RNA by performing experiments in which they selectively depleted it from stem cells. hESCs are actively maintained in a so-called 'pluripotent' state, from which they are capable of developing into any cell type in the human body (see image). In the absence of HERV-H RNA, hESCs rapidly lost their pluripotency; the researchers noted that the loss of HERV-H expression considerably altered the activity of many genes associated with cell development and proliferation.