Science & Technology


Unheralded mathematician Yitang Zhang bridges the prime gap

Yitang Zhang prime numbers
© University of New Hampshire
Yitang Zhang
On April 17, a paper arrived in the inbox of Annals of Mathematics, one of the discipline's preeminent journals. Written by a mathematician virtually unknown to the experts in his field - a 50-something lecturer at the University of New Hampshire named Yitang Zhang - the paper claimed to have taken a huge step forward in understanding one of mathematics' oldest problems, the twin primes conjecture.

Editors of prominent mathematics journals are used to fielding grandiose claims from obscure authors, but this paper was different. Written with crystalline clarity and a total command of the topic's current state of the art, it was evidently a serious piece of work, and the Annals editors decided to put it on the fast track.

Just three weeks later - a blink of an eye compared to the usual pace of mathematics journals - Zhang received the referee report on his paper.

"The main results are of the first rank," one of the referees wrote. The author had proved "a landmark theorem in the distribution of prime numbers."

Rumors swept through the mathematics community that a great advance had been made by a researcher no one seemed to know - someone whose talents had been so overlooked after he earned his doctorate in 1991 that he had found it difficult to get an academic job, working for several years as an accountant and even in a Subway sandwich shop.

"Basically, no one knows him," said Andrew Granville, a number theorist at the Université de Montréal. "Now, suddenly, he has proved one of the great results in the history of number theory."

Mathematicians at Harvard University hastily arranged for Zhang to present his work to a packed audience there on May 13. As details of his work have emerged, it has become clear that Zhang achieved his result not via a radically new approach to the problem, but by applying existing methods with great perseverance.

"The big experts in the field had already tried to make this approach work," Granville said. "He's not a known expert, but he succeeded where all the experts had failed."

Fluid experiments point to the alternative pilot wave interpretation of quantum reality

bouncing droplet
© John Bush
A droplet bouncing on the surface of a liquid has been found to exhibit many quantum-like properties, including double-slit interference, tunneling and energy quantization.
For nearly a century, "reality" has been a murky concept. The laws of quantum physics seem to suggest that particles spend much of their time in a ghostly state, lacking even basic properties such as a definite location and instead existing everywhere and nowhere at once. Only when a particle is measured does it suddenly materialize, appearing to pick its position as if by a roll of the dice.

This idea that nature is inherently probabilistic - that particles have no hard properties, only likelihoods, until they are observed - is directly implied by the standard equations of quantum mechanics. But now a set of surprising experiments with fluids has revived old skepticism about that worldview. The bizarre results are fueling interest in an almost forgotten version of quantum mechanics, one that never gave up the idea of a single, concrete reality.

The experiments involve an oil droplet that bounces along the surface of a liquid. The droplet gently sloshes the liquid with every bounce. At the same time, ripples from past bounces affect its course. The droplet's interaction with its own ripples, which form what's known as a pilot wave, causes it to exhibit behaviors previously thought to be peculiar to elementary particles - including behaviors seen as evidence that these particles are spread through space like waves, without any specific location, until they are measured.

Particles at the quantum scale seem to do things that human-scale objects do not do. They can tunnel through barriers, spontaneously arise or annihilate, and occupy discrete energy levels. This new body of research reveals that oil droplets, when guided by pilot waves, also exhibit these quantum-like features.

To some researchers, the experiments suggest that quantum objects are as definite as droplets, and that they too are guided by pilot waves - in this case, fluid-like undulations in space and time. These arguments have injected new life into a deterministic (as opposed to probabilistic) theory of the microscopic world first proposed, and rejected, at the birth of quantum mechanics.

"This is a classical system that exhibits behavior that people previously thought was exclusive to the quantum realm, and we can say why," said John Bush, a professor of applied mathematics at the Massachusetts Institute of Technology who has led several recent bouncing-droplet experiments. "The more things we understand and can provide a physical rationale for, the more difficult it will be to defend the 'quantum mechanics is magic' perspective."

Total lunar eclipse on Wednesday will be a rare 'selenelion'

Lunar Eclipse
© Ron Delvaux via The Virtual Telescope Project
A photo of the first total lunar eclipse of 2014 taken from Arizona.
Observers of Wednesday morning's total lunar eclipse might be able to catch sight of an extremely rare cosmic sight.

On Oct. 8, Interested skywatchers should attempt to see the total eclipse of the moon and the rising sun simultaneously. The little-used name for this effect is called a "selenelion," a phenomenon that celestial geometry says cannot happen.

And indeed, during a lunar eclipse, the sun and moon are exactly 180 degrees apart in the sky. In a perfect alignment like this (called a "syzygy"), such an observation would seem impossible.

But thanks to Earth's atmosphere, the images of both the sun and moon are apparently lifted above the horizon by atmospheric refraction. This allows people on Earth to see the sun for several extra minutes before it actually has risen and the moon for several extra minutes after it has actually set. [How to See the Total Lunar Eclipse (Visibility Maps)]

As a consequence of this atmospheric trick, for many localities east of the Mississippi River, watchers will have a chance to observe this unusual sight firsthand. Weather permitting, you could have a short window of roughly 2 to 9 minutes (depending on your location) with the possibility of simultaneously seeing the sun rising in the east while the eclipsed full moon is setting in the west.

One foggy day on St. Paul Island, a woolly mammoth stepped onto a trapdoor of greenery...

© Ned Rozell
St. Paul Island in the Bering Sea.
One foggy day on St. Paul Island, a woolly mammoth stepped onto a trapdoor of greenery. It plunged thirty feet to the floor of a cave. There was no exit.

A few thousand years later, a scientist who descended by ladder found the mammoth's tooth amid the bones of other mammoths, polar bears, caribou, reindeer and arctic foxes. Radiocarbon dating showed the mammoth died about 6,500 years ago. Here was proof that mammoths lived on the Bering Sea island thousands of years after the creatures vanished from mainland Alaska

There began a detective story that attracted a widespread team of scientists. They were curious about what finished off the resilient St. Paul mammoth: People with spears and clubs? Polar bears? Disease? Starvation? A volcanic eruption?

Mat Wooller was part of a group that visited the island a few years ago to pull a core from a crater lake. In the cylinder of mud, which dust and pollen from thousands of years ago, the scientists hoped to find evidence of mammoths, the environment in which they lived, and when they might have vanished. Their clues included the presence of pollen grains and a fungus that lived on animal dung like that dropped by mammoths. Beth Shapiro and her colleagues from UCLA are part of the team looking for DNA the mammoths shed in or around the lake.

And the Blood moon returns: Another total lunar eclipse will color the moon blood red

The second blood moon of 2014 is approaching. The first appeared April 14-15, and this week's is the second in a 'tetrad,' or series of four. Skywatchers across much of the world will have the chance to see the moon glowing with an eerie red pallor during a pre-Halloween total lunar eclipse next week.
A visibility map of the total lunar eclipse rising on Oct. 8, 2014. Stargazers in Africa and Europe will miss the 'blood moon,' but most of North America and Asia will get a good show of this long-lasting event.
The "blood moon" total lunar eclipse will rise during the full moon of Oct. 8 just before sunrise in North America, but red might not be the only color people see during the total eclipse. Weather permitting, it's possible that some sharp-eyed observers might be able to see some blue in the moon's glow. The event will be the second of four consecutive total lunar eclipses in 2014 and 2015, according to NASA officials.

Scientists find elusive particle that is both matter and antimatter

Majorana fermion
© Ali Yazdani Lab
The experiment revealed the atomic structure of the iron wire on a lead surface. The zoomed-in portion of the image depicts the probability of the wire containing the Majorana fermion. Importantly, the image pinpoints the particle to the end of the wire, which is where it had been predicted to be over years of theoretical calculations.
Scientists from Princeton University have discovered an unusual new type of particle that is essentially its own antiparticle - behaving simultaneously like matter and antimatter, according to a new study currently appearing in the online edition of the journal Science.

The particle, which is known as a Majorana fermion, was detected and imaged using a two-story-tall microscope floating in an ultralow-vibration lab, the researchers explained. Not only is the discovery "an exciting step forward for particle physics, explained Macrina Cooper-White of The Huffington Post, but it could also impact quantum computer development.

"This is the most direct way of looking for the Majorana fermion since it is expected to emerge at the edge of certain materials," Princeton physics professor and lead investigator Ali Yazdani said in a statement Thursday. "If you want to find this particle within a material you have to use such a microscope, which allows you to see where it actually is."
Eye 2

Facebook may begin tracking subscribers health information to facilitate its entry into healthcare market

Facebook is watching you
© Inconnu
It's no secret that Facebook tracks users' friendships and monitors their interests for advertising placement - but now sources tell Reuters the social networking site is also curious about subscribers' health information.

Three people familiar with discussions underway at the social media giant told Reuters that the company is interested in expanding into healthcare, and has been meeting with medical providers and experts.

As the plans are in development, the individuals requested anonymity but said that Facebook "is setting up a research and development unit to test new health app...[for] support communities...[and] new preventative care applications that would help people improve their lifestyles."

Comment: Which means that those whose healthcare choices go against the mainstream, i.e. anti-vaccine advocates, will be duly noted. But of course, the NSA is already using Facebook to hack into individual computers, so in all likelihood such information has been stored for future need.

Surveillance state: NSA using Facebook to hack into your computer

Fireball 5

To find meteorites, listen to the legends of Australian aborigines

Henbury Meteorites Conservation Reserve
© Flickr user Matthias Siegel
One of the 4,700-year-old impact craters at Henbury Meteorites Conservation Reserve in Australia.
In the heart of Australia, at a remote site south of Alice Springs, the land is pitted with about a dozen strange depressions. Don't drink the rainwater that pools there, or a fire devil will fill you with iron.

So goes one Aboriginal tale that has been passed down across generations. The site is the Henbury meteorite field, which was created about 4,700 years ago when a large, iron-filled meteorite slammed into Earth's atmosphere and broke apart, scattering fragments. The Aboriginal warning is perhaps one of the clearest examples of an oral tradition that has preserved the memory of an ancient meteorite strike, argues Duane Hamacher at the University of New South Wales in Australia. According to Hamacher, such tales may be vital clues pointing toward future finds.

"These traditions could lead to the discovery of meteorites and impact sites previously unknown to Western science," he writes in a paper that will appear in an upcoming issue of Archaeoastronomy and that was published online August 27.

Most myths and tales are just stories passed down through the ages, altered over time like a vast game of "Telephone." But some are based on actual geological or astronomical events that occurred long ago. The search for the truth behind those stories has inspired a field of science called geomythology.

A solar cell that stores its own power: World's first 'solar battery' runs on light and air

solar battery
© Yiying Wu/The Ohio State University
Researchers at the Ohio State University have invented a solar battery -- a combination solar cell and battery -- which recharges itself using air and light.
Is it a solar cell? Or a rechargeable battery? Actually, the patent-pending device invented at The Ohio State University is both: the world's first solar battery.

In the October 3, 2014 issue of the journal Nature Communications, the researchers report that they've succeeded in combining a battery and a solar cell into one hybrid device.

Key to the innovation is a mesh solar panel, which allows air to enter the battery, and a special process for transferring electrons between the solar panel and the battery electrode. Inside the device, light and oxygen enable different parts of the chemical reactions that charge the battery.

The university will license the solar battery to industry, where Yiying Wu, professor of chemistry and biochemistry at Ohio State, says it will help tame the costs of renewable energy.

"The state of the art is to use a solar panel to capture the light, and then use a cheap battery to store the energy," Wu said. "We've integrated both functions into one device. Any time you can do that, you reduce cost."

Researcher studies possibility of metal snow on Venus

Erika Kohler
Erika Kohler places thermocouples into a pressure chamber at NASA's Goddard Space Flight Center. The thermocouples measure the temperature of the chamber to ensure it reaches Venusian temperatures.
Is it snowing metal on Venus? Erika Kohler is trying to find out.

Kohler, a doctoral candidate in the Arkansas Center for Space and Planetary Sciences at the University of Arkansas, returned to campus last month after a summer-long fellowship at NASA's Goddard Space Flight Center in Maryland, where she performed experiments in the facility's pressure chamber to simulate Venusian conditions.

"My dissertation is focusing on metal condensates in planetary atmospheres," said Kohler, who is the only student in the Space and Planetary Sciences Center currently researching Venus. "I have been primarily looking at the stability of materials on Venus and determining what can exist at certain altitudes. I'm finding that there are different forms of iron compounds or mercury compounds that can exist at these conditions."

Venus, the second planet from the sun, is both the closest planet to Earth and the planet closest in size to Earth. But the conditions on the planet are radically different than ours. The average daily temperature is 860 degrees Fahrenheit, for instance. And the atmosphere is so dense that there are only a handful of actual photographs of the Venusian surface; most images of Venus are created through radar imaging.