“We call it fishing for electrons.” That’s environmental engineer Craig Criddle describing a new way that he and his colleagues have discovered for generating electricity from sewage.

Wait. What?

Brilliant, right? The Stanford team hopes this breakthrough technology will be used to harvest energy in places such as sewage treatment plants, or to break down organic pollutants in the “dead zones” of lakes and coastal waters where fertilizer runoff and other organic waste can deplete oxygen levels and suffocate marine life.

And this new power all starts with wired microbes. The mini power plants produce electricity as they digest plant and animal waste from wastewater. Right now, still in the laboratory phase, their prototype is about the size of a D-cell battery and looks like a chemistry experiment, with two electrodes, one positive, the other negative, plunged into a bottle of wastewater.

Inside that murky vial, attached to the negative electrode like barnacles to a ship’s hull, an unusual type of bacteria feast on particles of organic waste and produce electricity, which is captured by the battery’s positive electrode.

Scientists have long known of the existence of what they call exoelectrogenic microbes—organisms that evolved in airless environments and developed the ability to react with oxide minerals rather than breathe oxygen as we do, to convert organic nutrients into biological fuel.

Over the past dozen years or so, several research groups have tried various ways to use these microbes as bio-generators, but tapping this energy efficiently has proven challenging. Part of that challenge for the Stanford team is the cost of the oxide minerals necessary to make it happen. “We demonstrated the principle using silver oxide, but silver is too expensive for use at large scale,” says team member Yi Cui. “Though the search is underway for a more practical material, finding a substitute will take time.”

The Stanford engineers estimate that the microbial battery can extract about 30 percent of the potential energy locked up in wastewater. That is roughly the same efficiency at which the best commercially available solar cells convert sunlight into electricity.

Their study was published recently in the Proceedings of the National Academy of Sciences.

Image: Xing Xie, Stanford University

Can scientists pull off a real-life version of Jurassic Park?  This intriguing question received a lot of attention earlier this year, when Revive & Restore (a project of the San Francisco-based Long Now Foundation) announced their goal of reviving extinct species using cutting-edge DNA technology. Dinosaurs have been gone too long for DNA to still be intact, but animals that went extinct during human history could potentially make a comeback. One of the first candidates for “de-extinction”—the iconic passenger pigeon (Ectopistes migratorius).

In the early 1800s, the passenger pigeon was the world’s most abundant bird species, even though its range was limited to eastern and central North America. Flocks of passenger pigeons—which sometimes included millions of birds—were so vast, they darkened swaths of sky up to a mile wide. But intensive hunting and habitat destruction by humans drove this species to extinction in a shockingly short span of time. The last passenger pigeon, “Martha,” died in 1914 at the Cincinnati Zoo. Her body remains at the Smithsonian’s National Museum of Natural History.

The Academy’s research collection houses nine specimens and three eggs of this species, dating to the late 1800s. Century-old specimens like these can still provide valuable information for modern-day studies. For example, Academy curator Jack Dumbacher and his colleagues published a paper in 2010 revealing that the closest living relative of the passenger pigeon is not the mourning dove, as many had suspected, but the band-tailed pigeon (Patagioenas fasciata), which is found along the Pacific coast and in the southwestern U.S., and can be seen in oak forests in the Bay Area. DNA sampling from museum specimens provided crucial data for this study. And the study’s conclusion provides critical information about which living relative could serve as a surrogate parent for the passenger pigeon, as scientists move forward with trying to revive this lost species.

Science Today sat down with Jack Dumbacher, who is also a scientific advisor to the Long Now Foundation, for his insights into de-extinction.

Where does the process currently stand?
JD: The Long Now Foundation has assembled a team of scientists to tackle different aspects of this project. Graduate student Ben Novak, working in Beth Shapiro’s lab at UC Santa Cruz, is refining the sequencing of the passenger pigeon genome from museum specimens. The genome of the band-tailed pigeon (the closest living relative) is also being sequenced.

Once the genomes are assembled, what happens next?
JD: You have to compare the genomes to determine which stretches of DNA make a passenger pigeon a passenger pigeon. Then you take the genome of a band-tailed pigeon and convert those important stretches of DNA into passenger pigeon DNA. George Church’s lab at Harvard is working on ways to do this using “CRISPR” technology—using bacterial proteins to genetically engineer specific DNA sequences and direct mutations to occur in a predictable way.

Let’s say scientists successfully get this DNA into an embryo, and the embryo becomes a chick. Is it a true passenger pigeon?
JD: That’s the big challenge. It may still have some band-tailed pigeon DNA. And you have to think about its behavior. How will it learn to be a passenger pigeon, find food, and avoid predators? Teams of researchers are tackling these numerous considerations and challenges.

Some might say that extinct animals went extinct for a reason, and bringing them back is not a good idea. How would you respond
JD: Animals like the passenger pigeon and moa went extinct due to human activity. So going extinct “for a reason” was humans to begin with. Also, developing the technology to successfully de-extinct an animal would itself be an intellectual coup, one that might have unforeseen benefits. The technology could be useful in other aspects of life, like agriculture, animal husbandry, conservation of endangered species, and, potentially, even human health. Think of the Space Race and all the accompanying benefits to society that resulted from that fundamental scientific research and development.

What other ethical concerns have come up?
JD: The ideal goal is to release de-extincted passenger pigeons back into their native habitat. But you have to be careful not to harm any other species whose survival may be on the brink. Their original ecosystem (the forests of the eastern and central U.S.) has changed. You don’t want to upset the balance in a way that threatens additional species. But the idea of restoring a habitat with native species is not a new one. Biologists restore habitats all the time. Had the pigeon survived only in captivity, we would be excited to be able to re-release it. Having survived only in our freezers or museum drawers, is that so different?

How many years away are we from seeing a real, live passenger pigeon?
JD: Optimistically, I would be very excited if this could happen in the next five to ten years. If not, I am confident that some day, we will have the technology to do this. Now is a good time to start thinking critically about what such a technology and ability would mean.

Andrew Ng is Communications Manager at the California Academy of Sciences.

Has Voyager 1 finally left the Solar System?

An answer to this question has been proclaimed so many times in the last few years that it has almost lost its effect. Part of the confusion lies in how we define “solar system.” Is it the edge of planetary orbits or the end of the Sun’s influence…or is there yet another definition?

Launched in 1977, the craft has been hurtling through space at an incredible 38,000 miles per hour, sprinting nearly 1,000,000 miles per day. It passed the orbit of the farthest planet Neptune on August 25, 1989 (at the time, due to its highly elliptical orbit, the then-planet Pluto was closer to the Sun than Neptune). Its twin spacecraft, Voyager 2, actually flew close to the planet itself. In 1990, with their planetary missions accomplished, both Voyager missions were renamed the Voyager Interstellar Mission. This consists of three phases: detection of the termination shock (the edge of the Sun’s magnetic influence, where the solar wind slows); exploration of the heliopause (the interface between the solar wind and the interstellar wind); and exploration of interstellar space (the region where the interstellar wind dominates). In December 2004, Voyager crossed the termination shock. Roughly ten years later, the craft was expected to transverse the heliopause, which many consider the edge of the Solar System.

And on August 25, 2012, 35 years after its launch and 12 billion miles (125.3 AU) from the Sun, Voyager 1 officially crossed into interstellar space.

The determination that the event actually occurred, however, did not come until last week. What took so long?

The Sun ejects plasma material (called the “solar wind”) out into a bubble called the heliosphere. The plasma outside that sphere comes from stellar explosions millions of years ago and has since been dispersed throughout the galaxy. The interaction between the heliosphere and plasma is the boundary between the two.

Voyager was looking to detect that boundary between plasmas; however, it could not do this directly because the plasma detector on Voyager 1 malfunctioned in 1980, just a few years after launch. Instead, scientists measured the magnetic field of the Sun and of the interstellar wind. The change did not manifest as expected, so scientists could not draw a definite conclusion. Another set of instruments on board, two antennae, are able to measure plasma—but only if it is moving in waves. A solar eruption in March 2012 sent a shock wave that took 400 days to reach Voyager, but caused the plasma to react in a way that Voyager could detect. This signal finally enabled the confirmation of the craft’s passage into interstellar space.

Sadly, our connection with Voyager will eventually end as its power runs out (its current power output is about that of a refrigerator lightbulb—try detecting that from 11 billion miles away!) The craft is expected to lose all power and cease its communications with Earth by 2025. With no friction to slow it down, however, Voyager will continue to drift on, indefinitely. It remains well within the sphere of the Sun’s gravitational dominion, but will take about 30,000 years to pass through the Oort cloud, the cometary halo extending about a light year or so from the Sun and the farthest-known objects orbiting the Sun. So although the plucky spacecraft has entered interstellar space and left the Sun’s magnetic influence, the Voyager team says it will not yet leave the Solar System until it passes through the Oort Cloud. Beyond that, it will take another 70,000 years to travel the 4.3 light year distance between us and the next closest star, Alpha Centari.

But let’s not underestimate the significance of this event. A man-made object has left the confines of the tiny speck of our galactic home for the very first time and entered the space between stars. We have physically entered a space greater than any explored before and taken the first step in ever visiting other star systems. True, it is a mere 16 light hours, but substantially farther than the 1.3 light seconds to the Moon, which is the farthest that humans have gone.

Voyager leads the way in a whole new frontier of exploration.

Elise Ricard is the Senior Presenter at the Morrison Planetarium and holds a master’s degree in museum education.

Here’s a great idea for a super-power: what if by merely emitting a sound, you could detect nearby friends and enemies in the way the sound echoes? Echoes. Echoes.

For many species of bats and dolphins, echolocation isn’t a super-power but a necessity. It allows these animals to hear predators and prey without seeing them in the dark skies or cloudy oceans. This adaptation evolved separately in these mammals—a great example of convergent evolution.

Scientists at Queen Mary, University of London were curious how this type of convergent evolution looked at the genomic level. So they compared the complete genomes of 22 mammals, including new sequences of four bat species, to look at how echolocation is expressed in the genes.

To perform the analysis, the team had to sift through millions of “letters” of genetic code using a computer program developed to calculate the probability of convergent changes occurring by chance, so they could reliably identify “odd-man-out” genes.

Remarkably, they found genetic signatures consistent with convergence in nearly 200 different genomic regions! “We had expected to find identical changes in maybe a dozen or so genes but to see nearly 200 is incredible,” explains Queen Mary team member Joe Parker. “We know natural selection is a potent driver of gene sequence evolution, but identifying so many examples where it produces nearly identical results in the genetic sequences of totally unrelated animals is astonishing.”

Although many of the gene region similarities are in genes involved in hearing, which the team expected, others are all over the place, reports ScienceNOW:

…some genes with shared changes are important for vision, but most have functions that are unknown.

The team published their findings last week in Nature.

“These results could be the tip of the iceberg,” says group leader Stephen Rossiter. “As the genomes of more species are sequenced and studied, we may well see other striking cases of convergent adaptations being driven by identical genetic changes.”

So perhaps not a super-power, but a regular occurrence…

Image: Greg Hume

While there is no officially acknowledged “man in the moon,” there is a LADEE (channel your inner Scot as you say it, “lad-ee”), or there will be soon. NASA’s upcoming Lunar Atmosphere and Dust Environment Explorer (LADEE) is slated for launch today! This mission will give us a chance to revisit the lunar surface in great detail—and possibly determine the cause of some strange observations made decades ago during the Apollo missions.

When taking coronal photographs in 1971, the Apollo 15 astronauts found what they described as “excessive brightness” on the lunar surface. One objective of the LADEE mission is to determine the nature of this glow, thought to be a loose lunar atmosphere. (If an atmosphere exists, it’s much, MUCH less dense than ours.) The glow could also be caused by electrostatically charged dust that hovers around the lunar surface.

In order to get to the Moon, LADEE will take off on a Minotaur V launch vehicle, made from a converted peacekeeper missile—the first launch of its kind. It’s based on the Minotaur IV system, which has been used successfully many times.

After launch, LADEE will spend 30 days making its way to the Moon and establishing a stable orbit 156 kilometers above the surface; it will spend the next 30 days aligning, checking out, and tuning up its scientific instruments. The 100-day-long science portion of the mission will then allow NASA researchers to observe the lunar environment carefully and put to rest the 38-year-old mystery.

The tools onboard consist of an Ultraviolet and Visible Light Spectrometer (UVS), which will analyze chemical compounds and determine their elemental makeup; the Neutral Mass Spectrometer (NMS), which will help determine just how much atmosphere the moon has; and finally, the Lunar Dust Experiment (LDEX).

LADEE will also establish a higher bandwidth, more robust connection than any prior lunar mission, using laser-based communication instead of the traditional low-power radio-based system enabling more information to be sent faster. That’s right! NASA is deploying experimental space lasers to communicate with LADEE. How sci fi is that?

LADEE represents a synthesis of both new and well-tested technologies and a great chance for us to better understand our nearest neighbor in space.

Josh Roberts is a program presenter and astronomer at the California Academy of Sciences. He also contributes content to Morrison Planetarium productions.

Image: NASA EDGE

Maybe we ought to rethink those cavemen jokes. Researchers from the Max Planck Institute for Evolutionary Anthropology have discovered specialized bone tools made by Neanderthals more than 40,000 years ago.

The discovery leads scientists to challenge the notion that Neanderthals gained their tool-making skills from Homo sapiens—modern humans.

Neanderthals lived from about 200,000 to 28,000 years ago. Modern humans migrated to Europe about 40,000 years ago. Although evidence reveals that Neanderthals had cultural expression similar to modern humans, many anthropologists argue that these similarities only appear once modern humans came into contact with the original European group.

But the recent finds, leather-working tools called lissoirs, pre-date the arrival of modern humans. Lissoirs have been discovered at later Neanderthal and modern human sites and researchers believe the tools were used to fashion animal hides—making them softer and more waterproof. Modern artisans use similar tools today.

The earlier lissoirs were discovered at two sites in southwestern France. Using both radiocarbon dating and optically stimulated luminescence (OSL) dating to sediments at the site, the scientists estimate the date of the tools to close to 50,000 years ago, well before the arrival of modern humans.

“For now the bone tools from these two sites are one of the better pieces of evidence we have for Neanderthals developing on their own a technology previously associated only with modern humans,” explains Shannon McPherron, who discovered the lissoirs at one of the French excavation sites.

“If Neanderthals developed this type of bone tool on their own, it is possible that modern humans then acquired this technology from Neanderthals. Modern humans seem to have entered Europe with pointed bone-tools only, and soon after started to make lissoir[s]. This is the first possible evidence for transmission from Neanderthals to our direct ancestors,” says Marie Soressi, whose team found the bone tools at the other site.

Which species developed the tool first? We’ll let the anthropologists argue about that one…

The new findings are published this week in the Proceedings of the National Academy of Sciences.

Image courtesy of Abri Peyrony & Pech-de-l’Azé I Projects

Now this raven-sized early bird has had its brain examined. Amy Balanoff and her colleagues from the American Museum of Natural History recently took CT scans of more than two dozen specimens, including modern birds, Archaeopteryx, and closely related non-avian dinosaurs such as tyrannosaurs, to size up the different species’ brain power.

“Bird-brained” is actually a misnomer. (Crows demonstrate this again and again.) Modern birds are distinguished from reptiles by their brains, which are enlarged compared to body size. This “hyperinflation,” most obvious in the forebrain, is important for providing the superior vision and coordination required to fly.

By stitching together the CT scans, the scientists created 3D reconstructions of the skulls’ interiors. In addition to calculating the total volume of each digital brain cast, the research team also determined the size of each brain’s major anatomical regions, including the olfactory bulbs, cerebrum, optic lobes, cerebellum, and brain stem.

The researchers found that in terms of volumetric measurements, Archaeopteryx is not in a unique transitional position between non-avian dinosaurs and modern birds. Several other non-avian dinosaurs sampled, including bird-like oviraptorosaurs and troodontids, actually had larger brains relative to body size than Archaeopteryx.

“If Archaeopteryx had a flight-ready brain, which is almost certainly the case given its morphology, then so did at least some other non-avian dinosaurs,” Balanoff says.

“Archaeopteryx has always been set up as a uniquely transitional species between feathered dinosaurs and modern birds, a halfway point,” she says. “But by studying the cranial volume of closely related dinosaurs, we learned that Archaeopteryx might not have been so special.”

If not unique, where should we place Archaeopteryx in the tree of life? More research is needed. The current study is published this week in Nature.

Image: Amy Balanoff, American Museum of Natural History

Memories are unreliable, at least for humans.

According to MIT scientist (and Nobel Prize winner) Susumu Tonegawa, as quoted in Scientific American, only humans have false memories.

“Humans are the most amazing, imaginative animals,” he said. “We are thinking. Lots of things are going on. Humans are recording what happens and passing it on.”

An imperfect memory, Tonegawa said, may be the price we pay for the imagination and creativity that makes us human.

The phenomenon of humans’ false memory is well-documented—in many court cases, defendants have been found guilty on testimony from witnesses and victims who were sure of their recollections, but DNA evidence later overturned the conviction.

But now, Tonegawa and his colleagues have succeeded in also creating false memories in mice, hoping to further understand where and how these fake memories are made in the human brain.

Memories are stored in networks of neurons that form memory traces for each experience we have. Scientists call these traces engrams, and can identify the cells that make up part of an engram for a specific memory and reactivate it with a technology called optogenetics.

Using optogenetics, Tonegawa’s research team started the experiment by putting mice in a chamber and recording their memories of that chamber. The chamber was harmless and pleasant enough that the mice felt comfortable exploring the space. The next day, the researchers moved the mice into a different chamber, stimulating the memory of the previous chamber. The scientists also lightly shocked the rodents’ feet.

On the third day, the mice were placed back into the first chamber. They now froze in fear, even though they had never been shocked there. A false memory had been incepted—the mice feared the memory of the first chamber because when the shock was given in the second, they were reliving the memory of being in the first.

The team discovered they could both implant false memories and that the neurological traces of these false memories are identical in nature to those of authentic memories. “Whether it’s a false or genuine memory, the brain’s neural mechanism underlying the recall of the memory is the same,” says Tonegawa.

The MIT team is now planning further studies of how memories can be distorted in the brain.

The study is published in the current edition of Science.

Image: Steve Ramirez and Xu Liu