Strange New Nebula Is Missing Its Light Source

The discovery of a new and rarely seen nebula 10 billion light-years away has created a cosmic mystery: What is lighting up this dusty cloud of gases?

Researchers led by Zheng Cai, a postdoctoral fellow at the University of California, Santa Cruz, have discovered an "enormous Lyman-alpha nebula," or ELAN, only the third of these vast cosmic structures ever seen. A nebula is an interstellar cloud of gases and dust; an ELAN is a special kind of nebula, so named because it emits Lyman-alpha radiation — a particular wavelength of light emitted when the electron in a hydrogen atom drops down to its lowest energy level.

The two other ELANS previously discovered are nicknamed the Slug Nebula (for UC Santa Cruz's idiosyncratic mascot) and the Jackpot Nebula (because it contains a whopping four quasars, extremely bright objects created by particles accelerating away from black holes). But the new ELAN is a head-scratcher. The Slug and the Jackpot have bright quasars illuminating their dust and gases, but the light source inside the newfound ELAN is a mystery.

"What's really odd here, and one of the hooks of the story, is there's nothing," said Jason X Prochaska, a professor of astronomy and astrophysics at UC Santa Cruz and one of the authors of the paper reporting the new nebula, available on the physics preprint website ArXiv. "There's the faint smudge of a galaxy, probably, but no quasar shining toward us."

A peek at the early universe

The mysterious ELAN is named MAMMOTH-1, after the Mapping the Most Massive Overdensities Through Hydrogen (MAMMOTH) project, led by Cai, which turned up the strange nebula. The goal of the project is to search for dense areas in the early universe; because it takes light from MAMMOTH-1 about 10 billion years to reach Earth, scientists are looking back in time to about 3 billion years after the Big Bang. In particular, Prochaska said, the research team is searching for protoclusters, which are the precursors to galaxy clusters.

These are "the most massive single structures in the universe," Prochaska said.

Cai, Prochaska and their colleagues use light from quasars to find these protoclusters. When a quasar shines through a protocluster, the patterns of light absorption can reveal details about these networks of galaxies. The protocluster holding MAMMOTH-1 near its center — dubbed BOSS1441 — is around 50 million light-years across, the researchers found. Or was, anyway. By now, the protocluster will have collapsed into a smaller, more mature galaxy cluster, Prochaska said. (A light-year is about 5.9 trillion miles, or 9.5 trillion kilometers.)   

Looking for the light

ELANs are difficult to detect because they are so diffuse, Prochaska said. Directly observing one provides an opportunity to study how gases coalesce into galaxies, something that is usually possible only with computer simulations. [See Amazing Photos of Nebulas]

As for MAMMOTH-1's mysterious light source, the most likely candidate is an active galactic nucleus, or AGN, Prochaska said. (Quasars are one type of AGN.) Local dust, a few light-years from the AGN, may be obscuring it from view, he said. It should be easy to find the AGN by searching for infrared or longer wavelengths, Prochaska said.

"If we didn't see anything, that would kill that hypothesis, and we'd be scratching our heads," he said.

The research will be published in an upcoming issue of the Astrophysical Journal.

First Solid Sign that Matter Doesn't Behave Like Antimatter

One of the biggest mysteries in physics is why there's matter in the universe at all. This week, a group of physicists at the world's largest atom smasher, the Large Hadron Collider, might be closer to an answer: They found that particles in the same family as the protons and neutrons that make up familiar objects behave in a slightly different way from their antimatter counterparts.

While matter and antimatter have all of the same properties, antimatter particles carry charges that are the opposite of those in matter. In a block of iron, for example, the protons are positively charged and the electrons are negatively charged. A block of antimatter iron would have negatively charged antiprotons and positively charged antielectrons (known as positrons). If matter and antimatter come in contact, they annihilate each other and turn into photons (or occasionally, a few lightweight particles such as neutrinos). Other than that, a piece of matter and antimatter should behave in the same way, and even look the same — a phenomenon called charge-parity (CP) symmetry.

But if there were a violation to this symmetry — meaning some bit of antimatter were to behave in a way that was different from its matter counterpart — perhaps that difference could explain why matter exists today.

To look for this violation, physicists at the Large Hadron Collider, a 17-mille-long (27 kilometers) ring beneath Switzerland and France, observed a particle called a lambda-b baryon. Baryons include the class of particles that make up ordinary matter; protons and neutrons are baryons. Baryons are made of quarks, and antimatter baryons are made of antiquarks. Both quarks and antiquarks come in six "flavors": up, down, top, bottom (or beauty), strange and charm, as scientists call the different varieties. A lambda-b is made of one up, one down and one bottom quark. (A proton is made of two up and one down, while a neutron consists of two down and one up quark.)

If the lambda and its antimatter sibling show CP symmetry, then they would be expected to decay in the same way. Instead, the team found that the lambda-b and antilambda-b particles decayed differently. Lambdas decay in two ways: into a proton and two charged particles called pi mesons (or pions), or into a proton and two K mesons (or kaons). When particles decay, they throw off their daughter particles at a certain set of angles. The matter and antimatter lambdas did that, but the angles were different. [7 Strange Facts About Quarks]

This is not the first time matter and antimatter have behaved differently. In the 1960s, scientists studied kaons themselves, which also decayed in a way that was different from their antimatter counterparts. B mesons — which consist of a bottom quark and an up, down, strange or charm quark — have also shown similar "violating" behavior.

Mesons, though, are not quite like baryons. Mesons are pairs of quarks and antiquarks. Baryons are made of ordinary quarks only, and antibaryons are made of antiquarks only. Discrepancies between baryon and antibaryon decays had never been observed before.

"Now we have something for baryons," Marcin Kucharczyk, an associate professor at the Institute of Nuclear Physics of the Polish Academy of Sciences, which collaborated on the LHC experiment, told Live Science. "When you'd observed mesons, it was not obvious that for baryons it was the same."

While tantalizing, the results were not quite solid enough to count as a discovery. For physicists, the measure of statistical significance, which is a way of checking whether one's data could happen by chance, is 5 sigma. Sigma refers to standard deviations, and a 5 means that there is only a 1 in 3.5 million chance that the results would occur by chance. This experiment got to 3.3 sigma — good, but not quite there yet. (That is, 3.3 sigma means that there's about a 1 in 4,200 chance that the observation would have occurred randomly, or about a 99-percent confidence level.)

The findings are not a complete answer to the mystery of why matter dominates the universe, Kucharczyk said.

"It cannot explain the asymmetry fully," he said. "In the future, we will have more statistics, and maybe for other baryons."

The findings are detailed in the Jan. 30 issue of the journal Nature Physics.Besides the identical behavior, CP symmetry also implies that the amount of matter and antimatter that was formed at the Big Bang, some 13.7 billion years ago, should have been equal. Clearly it was not, because if that were the case, then all the matter and antimatter in the universe would have been annihilated at the start, and even humans wouldn't be here.

Has the Large Hadron Collider Disproved the Existence of Ghosts?

The Large Hadron Collider (LHC) might be the world's most incredible science experiment. A particle collider seventeen miles in circumference, it accelerates protons to velocities approaching the speed of light and slams them together. Enthralled scientists from all over the world watch the subatomic demolition derby and record what happens. Thus far, they've witnessed the creation of quark-gluon plasma (the densest matter outside of black holes), found key evidence against supersymmetry, and discovered the Higgs boson, a result which garnered the Nobel Prize in Physics.

Much of the general public probably isn't aware of these fascinating, yet unfortunately, esoteric discoveries at the LHC. Particle physics simply doesn't inspire as much interest as say, ghosts. At least four in ten Americans believe in ghosts, and it's likely that even fewer people are aware of the LHC. On that note, at least one physicist contends that the LHC has, in fact, disproved the existence of ghosts.

The physicist in question is Brian Cox, an Advanced Fellow of particle physics at the University of Manchester and a popular science communicator in Britain. On a recent broadcast of BBC Radio Four's The Infinite Monkey Cage centered around science and the paranormal, Cox had this to say on the topic:

"Before we ask the first question, I want to make a statement: We are not here to debate the existence of ghosts because they don't exist."

He continued:

"If we want some sort of pattern that carries information about our living cells to persist then we must specify precisely what medium carries that pattern and how it interacts with the matter particles out of which our bodies are made. We must, in other words, invent an extension to the Standard Model of Particle Physics that has escaped detection at the Large Hadron Collider. That's almost inconceivable at the energy scales typical of the particle interactions in our bodies."

Astrophysicist Neil deGrasse Tyson, who was also on the show, pressed Cox to clarify his statement.

"If I understand what you just declared, you just asserted that CERN, the European Center for Nuclear Research, disproved the existence of ghosts."

"Yes," Cox replied.

"I would say if there's some kind of substance that's driving our bodies, making my arms move and legs move, then it must interact with the particles out of which our bodies are made. And seeing as we've made high precision measurements of the ways that particles interact, then my assertion is there can be no such thing as an energy source that's driving our bodies."

While there are numerous scientific explanations that effectively debunk the paranormal, this was a novel contention. And it makes sense. If ghosts are impinging on the physical world, then surely their wispy trails would be detected by physicists. Unsurprisingly, this hasn't happened.

8 Mammals That Have Been Cloned Since Dolly the Sheep

20 Years Since 'Dolly'

It was 20 years ago this week that scientists announced the first successful cloning of a mammal — the now-famous sheep Dolly — from a cell taken from an adult animal.

The cloning of Dolly by the team at The Roslin Institute, at the University of Edinburgh in Scotland, paved the way for researchers to try cloning a number of other mammals. Prior to Dolly, scientists had been able to clone mammals only by splitting growing embryos.

Since the announcement of Dolly's birth, dozens of other species have been cloned from adult body cells, including many mammals. Here are eight of the mammals that have been cloned in this manner since Dolly:

Robot 'Telepathy' Could Make Self-Driving Cars Safer

Are you nervous about entrusting your life to a self-driving car? What if you could telepathically communicate with the vehicle to instantaneously let it know if it makes a mistake?

That is the ultimate promise of technology being developed by a team fromBoston University and the Computer Science and Artificial Intelligence Laboratory (CSAIL) at the Massachusetts Institute of Technology. The tech uses brain signals to automatically correct a robot's errors.

Using a so-called brain-computer interface (BCI) to communicate with a robot is not new, but most methods require people to train with the BCI and even learn to modulate their thoughts to help the machine understand, the researchers said.

By relying on brain signals called "error-related potentials" (ErrPs) that occur automatically when humans make a mistake or spot someone else making one, the researchers' approach allows even complete novices to control a robot with their minds, the researchers in the new study said. This can be done by simply agreeing or disagreeing with whatever actions the bot takes, the researchers said.

Working with machines

This technology could offer an intuitive and instantaneous way of communicating with machines, for applications as diverse as supervising factory robots to controlling robotic prostheses, the researchers said.

"When humans and robots work together, you basically have to learn the language of the robot, learn a new way to communicate with it, adapt to its interface," said Joseph DelPreto, a Ph.D. candidate at CSAIL who worked on the project.

"In this work, we were interested in seeing how you can have the robot adapt to us rather than the other way around," he told Live Science.

The new research was published online Monday (March 6) and will be presented at the IEEE International Conference on Robotics and Automation (ICRA) in Singapore this May. In the study, the researchers described how they collected electroencephalography (EEG) data from volunteers as those individuals watched a common type of industrial humanoid robot, called Baxter, decide which of two objects to pick up.

This data was analyzed using machine-learning algorithms that can detect ErrPs in just 10 to 30 milliseconds. This means results could be fed back to the robot in real time, allowing it to correct its course midway, the researchers said.

Refining the system

The system's accuracy needs significant improvement, the team admitted. In real-time experiments, the bot performed only slightly better than 50/50, or chance, when classifying brain signals as ErrPs. That meant that nearly half the time it would fail to notice the correction from the observer.

And even in more leisurely, offline analysis, the system still got it right only roughly 65 percent of the time, the researchers said.

But when the machine missed an ErrP signal and failed to correct its course (or change course when there was no ErrP), the human observer typically produced a second, stronger ErrP, said CSAIL research scientist Stephanie Gil.

"When we analyze that offline, we found that the performance boosts by a lot, as high as 86 percent, and we estimate we could get this upwards of 90 percent in the future. So our next step is to actually detect those in real time as well and start moving closer towards our goal of actually controlling these robots accurately and reliably on the fly," Gil told Live Science. 

Doing this will be tricky, though, because the system needs to be told when to look out for the ErrP signal, the researchers said. At present, this is done using a mechanical switch that gets activated when the robot's arm starts to move.

A secondary error won’t be created until after the robot's arm is already moving, so this switch won't be able to signal to the system to look for an ErrP, the researchers said. This means the system will have to be redesigned to provide another prompt, they added.

Now what?

The study is well-written, said Klaus-Robert Müller, a professor at the Technical University of Berlin, who was not involved with the new research but has also worked on BCIs that exploit these error signals. But, he said using ErrPs to control machines is not particularly new and he also raises concerns about the low ErrP classification ratesthe group achieved.

José del R. Millán, an associate professor at the École Polytechnique Fédérale de Lausanne in Switzerland, said he agrees that the performance of the group's ErrP decoder was low. But he thinks the approach they've taken is still "very promising," he added.

Millán's group has used ErrP signals to teach a robotic arm the best way to move to a target location. In a 2015 study published in the journal Scientific Reports, Millán and his colleagues described how the arm in their work starts by making a random movement, which the human observer decides is either correct or incorrect.

Through a machine-learning approach called reinforcement learning, the error signals are used to fine-tune the robot's approach, enabling the bot to learn the best movement strategy for a specific target. Millán said using ErrP to control robots could have broad applications in the future.

"I see it in use for any complex human-machine interaction where most of the burden is on the machine side, because of its capacity to do tasks almost autonomously, and humans are simply supervising," he said.

Black Death Couple? 2 Male Skeletons Found with Fingers Entwined

A 600-year-old mystery has surfaced from the tunnels of London's new Crossrail network, as archaeologists unearthed the skeletons of two men who were buried apparently holding hands.

Interred in a double grave, their heads both turned to the right and their fingers entwined, the two men stand out from the array of unusual finds uncovered since the Crossrail project began in 2009 to build a 26-mile (42 kilometers) rail line from West to East London.

The discovery, revealed at a new exhibit on the Crossrail findings, has indeed puzzled archaeologists at the Museum of London Archaeology, who carried out the excavation. They have suggested the men may have been related in some way, by blood or romance.

Bubonic plague?

Excavated from a cemetery near London's Smithfield meat market, which housed more than 50,000 corpses, the pair rested in the third and final layer of graves dating to the early 15th century.

An examination of the bones suggested that one man was between 36 and 45 years old when he died, and the other at least 46 years old at his death.

DNA tests on 12 of the 25 skeletons excavated from the cemetery revealed that fourwere positive for the bacteria Yersinia pestis, which causes the plague. The male hand-holders have yet to undergo DNA testing for the bacteria.

"This confirmed that the cemetery was used for the burial of Black Death victims," Don Walker, senior human osteologist at the Museum of London Archaeology, told Live Science.

He noted that the chances of obtaining a positive result from an infected individual is only about 30 percent, meaning it is difficult to isolate the bacteria even in infected individuals.

"The results suggest that a high proportion of the burials may have had plague," Walker said.

Walker believes that both men were indeed Black Death victims. [In Photos: 14th-Century 'Black Death' Grave Discovered]

They would have been infected during one of the bubonic plague epidemics that swept London in the years after the first, most deadly, outbreak in 1348, which wiped out more than half of the city's inhabitants.

Examination of the bones revealed that both individuals had tooth disease, probably caused in part by poor dental hygiene, and arthritis of the spine, often caused by heavy lifting or laboring.

"One also had a distinctive 'parry' fracture of the forearm. This was the most common long bone fracture in medieval London and may be caused by excess stress through activity or by the defensive action of parrying a blow aimed at the head," Walker said.

Who were these men?

Why the men have been holding hands for centuries remains a mystery.

"It was quite common for family members to be buried together if they died at or around the same time," Walker said. "They may have been brothers or had some other connection. Until DNA testing is done, we cannot be sure."

Another, less romantic, scenario is that the hands moved during the deterioration of the bodies.

"As the bodies were lying side-by-side, the hands may well have been close already," Walker said.

He noted the men may have been buried in shrouds, and the deterioration of the cloth holding the limbs close to the body could have allowed the arms to move.

"For example, the arms could have fallen off the hip onto the grave floor," Walker said.

During the Crossrail project, more than 200 archaeologists have managed to take an unprecedented slice down through London, unearthing more than 10,000 objects from 40 locations.

Apart from human remains, the findings include a piece of 55-million-year-old amber, bison and mammoth bones that are 68,000 years old, Roman artifacts, medieval ice skates, a Tudor bowling ball, 16th-century espadrilles-like leather shoes and an underground vault filled with Victorian-era ketchup and condiment bottles.

A wide range of the unearthed artifacts and fossils are on display in a new exhibition at the Museum of London Docklands until September 2017.

New Species! Tiny Frog and Fungus Gnat Get Celebrity Names

What does British naturalist and broadcaster Sir David Attenborough have in common with the Finnish founder of a symphonic metal band? Both recently inspired names for new species.

A newly described frog from Peru is the first amphibian named for Attenborough, who has already lent his name to various species of invertebrates, mammals, plants and reptiles, both living and extinct.

And a fungus gnat that lives in shadowy environments in the province of Lapland, Finland, is the first creature named for self-proclaimed "nature nerd" Tuomas Holopainen, musician and founding member of the band Nightwish, which combines head-banging heavy-metal music dynamics with classical instruments.

The species named for Attenborough, Pristimantis attenboroughi, will go by the common name Attenborough's rubber frog. Like others in its family, this fleshbelly frog does not have a tadpole stage. Researchers collected 34 specimens of the frog — 10 adult females, 11 adult males and three juveniles — in central Peru's Pui Pui Protected Forest at elevations between 11,155 feet and 12,913 feet (3,400 and 3,936 meters) above sea level.

The researchers found that the adult female frogs measured about 0.8 to 0.9 inches (19 to 23 millimeters) in length, and males were somewhat smaller — around 0.6 to 0.7 inches (15 to 19 mm). The adult frogs' coloration ranged from gray to green to red, whereas juveniles were lighter in color — yellowish or reddish brown — and patterned with darker spots and stripes. Scientists reported their findings in a new study, published today (March 7) in the journal ZooKeys.

Meanwhile, about 7,200 miles (11,600 kilometers) away in eastern Lapland, researchers were investigating a new species of fungus gnat, a type of tiny fly that inhabits and breeds in soil, and feeds on fungi.

Scientists found the gnat, which they named Sciophila holopaineni, in the Törmäoja conservation area in Savukoski, Finland, and described the newly discovered insect in a study published March 6 in the Biodiversity Data Journal. S. holopaineni's Finnish common name — "tuomaanvarjokainen" — further references Nightwish, referring to the band's latest album, "Endless Forms Most Beautiful," which touches on themes of biodiversity and evolution.

"I am very, very touched," Holopainen said in a statement, after he was asked to lend his name to the tiny insect. "This is the highest honor a nature nerd like me can receive."

Attenborough, of course, has received this honor multiple times. Before P. attenboroughi, his most recent namesake was the extinct marsupial mini-lion Microleo attenboroughi, which was described in July 2016 in the journal Palaeontologia Electronica.

2016 also marked a naming first forAttenborough: A research vessel destined to explore polar oceans was dubbed the "Sir David Attenborough" on May 6, shortly before his 90th birthday. However, although Attenborough's name is usually a first pick for researchers, in this case, his moniker was chosen to replace another name that was the overwhelming favorite in an internet poll — the somewhat less dignified "Boaty McBoatface."