Amazing Science
442.6K views | +23 today
Scooped by Dr. Stefan Gruenwald
onto Amazing Science!

Can we make objects that 'make themselves'?

Can we make objects that 'make themselves'? | Amazing Science |


Many are only just getting their heads around the idea of 3D printing but scientists at MIT are already working on an upgrade: 4D printing. At the TED conference in Los Angeles, architect and computer scientist Skylar Tibbits showed how the process allows objects to self-assemble. It could be used to install objects in hard-to-reach places such as underground water pipes, he suggested. It might also herald an age of self-assembling furniture, said experts.


TED fellow Mr Tibbits, from the MIT's (Massachusetts Institute of Technology) self-assembly lab, explained what the extra dimension involved. "We're proposing that the fourth dimension is time and that over time static objects will transform and adapt."


The process uses a specialised 3D printer made by Stratasys that can create multi-layered materials. It combines a strand of standard plastic with a layer made from a "smart" material that can absorb water. The water acts as an energy source for the material to expand once it is printed.


"The rigid material becomes a structure and the other layer is the force that can start bending and twisting it," said Mr Tibbits. "Essentially the printing is nothing new, it is about what happens after," he added. Such a process could in future be used to build furniture, bikes, cars and even buildings, he thinks.


For the time being he is seeking a manufacturing partner to explore the innovation. "We are looking for applications and products that wouldn't be possible without these materials," he added. "Imagine water pipes that can expand to cope with different capacities or flows and save digging up the street."

No comment yet.
Amazing Science
Your new post is loading...
Scooped by Dr. Stefan Gruenwald!

20,000+ FREE Online Science and Technology Lectures from Top Universities




This newsletter is aggregated from over 1450 news sources:


All my Tweets and Scoop.It! posts sorted and searchable:



You can search through all the articles semantically on my

archived twitter feed




You can also type your own query:



Or CLICK on the little

FUNNEL symbol at the

 top right of the screen




Your knowledge is your strength and power 


Acceso gratuito a documentos de las mejores universidades del mundo



Scooped by Dr. Stefan Gruenwald!

Google Tests First Error Correction in Quantum Computing

Google Tests First Error Correction in Quantum Computing | Amazing Science |













Quantum computers are coming... :D

Scooped by Dr. Stefan Gruenwald!

Most Luminous Known Galaxy Shines Brighter Than Light of 300 Trillion Suns






No comment yet.
Scooped by Dr. Stefan Gruenwald!

Ice loss in Antarctica so large that it affects Earth's gravity field





No comment yet.
Scooped by Dr. Stefan Gruenwald!

Oldest-known stone tools pre-date Homo






No comment yet.
Scooped by Dr. Stefan Gruenwald!

A 3D-printed mini jet engine that performs at 33,000 RPM






No comment yet.
Scooped by Dr. Stefan Gruenwald!

First fully warm-blooded fish found: The opah or moonfish









No comment yet.
Scooped by Dr. Stefan Gruenwald!

Mystery botnet hijacks broadband routers to offer DDoS-for-hire









No comment yet.
Scooped by Dr. Stefan Gruenwald!

Scientists Describe New DNA Base, N6-methyladenine, Bringing Count up to 8

Scientists Describe New DNA Base, N6-methyladenine, Bringing Count up to 8 | Amazing Science |

DNA, the genetic material of all living things, is what makes us who we are. Written in this molecular code are the instructions for making proteins, which are the building blocks of cells and thus living organisms. In natural circumstances, this code is formed of four basic units, or “letters”: A, C, G and T (adenine, cytosine, guanine and thymine). These so-called DNA bases pair up, A with T and C with G, forming a long, readable sequence that varies from gene to gene. Textbooks will tell you that it is those four letters that are the recipe for life, or so we long believed.

Back in the ‘80s, scientists threw another base into the mix: 5-methylcytosine (mC). As the name suggests, mC is cytosine with a functional unit called methyl attached. But it was not for another decade that scientists realized the importance of mC: The addition of methyl groups to DNA can switch genes on or off in order to meet the needs of each tissue, given that every cell contains the same DNA sequences. Such modifications are known as epigenetic changes; these allow the environment to affect gene expression, but they also play a role in various diseases. For example, alterations in mC have been shown to contribute to the development of cancer, amongst many other conditions.

But it turns out that the DNA alphabet does not even end here, as in recent years scientists have gradually expanded this list to eight. Now, scientists have just detailed descriptions of one more potential candidate, N6-methyladenine (6mA), in the journal Cell. As with mC, this is composed of the base adenine with a methyl group tacked onto it. While scientists have known about this modified base for some time, it was thought to have exclusively existed in bacteria, where it serves to protect against the unwanted addition of foreign DNA from other organisms.

Now, a group of researchers from IDIBELL-Bellvitge Biomedical Research Institute have found that this is not the case, providing evidence that 6mA is not simply a phenomenon of primitive cells. As described in the journal Cell, scientists found that some more complex cells, called eukaryotic cells, also possess the base. Eukaryotes are organisms within one of the three domains of life, the others being archaea and bacteria.

More specifically, researchers discovered 6mA in three different groups of eukaryotes: green algae, flies and worms. This was made possible through the development of highly sensitive analytical techniques, which picked up the exceedingly low levels of this base that previously eluded detection. Interestingly, newly gathered data indicates that, like mC, 6mA may also have a gene regulatory function in these animals, which could suggest that it also behaves as an epigenetic mark.

Now that scientists have found this base in various organisms, the researchers want to scrutinize our own genomes to see if it also exists in humans. This would be interesting given the fact that evidence seems to suggest that 6mA may play a role in stem cells. If it does indeed exist in our own species, then researchers may have a job on their hands trying to figure out what precise role it plays in the cell. 

No comment yet.
Scooped by Dr. Stefan Gruenwald!

Specialized brain cells of the entorhinal cortex are behind a 'sense of direction'

Specialized brain cells of the entorhinal cortex are behind a 'sense of direction' | Amazing Science |
After wandering around an unfamiliar part of town, can you sense which direction to travel to get back to the subway or your car? If so, you can thank your entorhinal cortex, a brain area recently identified as being responsible for our sense of direction. Variation in the signals in this area might even explain why some people are better navigators than others.

The new work adds to a growing understanding of how our brain knows where we are. Groundbreaking discoveries in this field won last year's Nobel Prize in Physiology or Medicine for John O'Keefe, a neuroscientist at University College London, who discovered “place cells” in the hippocampus, a brain region most associated with memory. These cells activate when we move into a specific location, so that groups of them form a map of the environment.

O'Keefe shared the prize with his former students Edvard Moser and May-Britt Moser, both now at the Kavli Institute for Systems Neuroscience in Norway, who discovered “grid cells” in the entorhinal cortex, a region adjacent to the hippocampus. Grid cells have been called the brain's GPS system. They are thought to tell us where we are relative to where we started.

A third type—head-direction cells, also found in the entorhinal region—fires when we face a certain direction (such as “toward the mountain”). Together these specialized neurons appear to enable navigation, but precisely how is still unclear. For instance, in addition to knowing which direction we are facing, we need to know which direction to travel. Little was known about how or where such a goal-direction signal might be generated in the brain until the new study.

A team of researchers, led by Hugo Spiers of University College London, asked 16 volunteers to familiarize themselves with a virtual environment consisting of a square courtyard with a landscape (such as a forest or a mountain) on each wall and a unique object in each corner. They then scanned the participants' brains while showing them views from the environment and asking them to indicate in which direction different objects lay.

The entorhinal region displayed a distinct pattern of activity when volunteers faced each direction—consistent with how head-direction cells should behave. The researchers discovered, however, that the same pattern appeared whether the volunteers were facing a specific direction or just thinking about it. The finding suggests that the same mechanism that signals head direction also simulates goal direction. How, exactly, the brain switches back and forth is unclear, but the researchers think the brain probably signals which direction you are facing until you consciously decide to think about where you want to go, at which point the same cells then run the simulation.
No comment yet.
Scooped by Dr. Stefan Gruenwald!

NASA visualizes 13 years of cloud covers on Earth

NASA visualizes 13 years of cloud covers on Earth | Amazing Science |


NASA Earth Observatory just published a map that uses data collected between July 2002 and April 2015 to give an unparalleled view of the world’s cloudy (and sunny) spots.

One thing that’s immediately apparent is that the world is a pretty cloudy place. It’s no surprise the U.K.—renowned for its dreary weather—appears in white, indicating frequent clouds. Ditto for the Amazon rainforest, which requires copious clouds for its prodigious rain.

On the flip side, the Sahara, Atacama, Arabian and their fellow deserts (including Antarctica) are basically cloud free. Australia and the western U.S. are also light on cloud cover.

Aside from giving a sense of the globe’s overall cloudiness, the map also reveals key features of the climate system. The band of cloudiness just around the equator generally represents the Intertropical Convergence Zone, a girdle of thunderstorms around the earth that form there thanks to warm, moist air lifting off the ocean. The ITCZ, as it’s known in climatespeak, generally drifts back and forth across the equator with the seasons.

In comparison, dry air generally subsides from 15-30 degrees north and south of the equator. Not surprisingly, that’s where most of the world’s deserts are located.

Erik Saether's curator insight, May 15, 12:35 AM

Places for world solar panels

Scooped by Dr. Stefan Gruenwald!

Many twin stars may actually be triplets

Many twin stars may actually be triplets | Amazing Science |

When it comes to stars, three may not be a crowd. That’s according to a new paper published online before print in Astronomy & Astrophysics, which suggests that almost a quarter of twin star systems might have another sibling nearby.

Astronomers examined the light from nearly 14,000 eclipsing binary stars, fortuitous arrangements in which a stellar pair’s orbit is edge-on from our point of view. Telescopes on Earth can’t see the individual stars, but they do observe dips in light intensity as one goes behind the other. For lone binary stars, those dips occur at regular intervals. But in the presence of a third star, this timing speeds up and slows down as the pair orbits its mate and gets nearer and farther from Earth. Researchers found that 2% of the eclipsing binaries had this signature swing back and forth. However, in another 22%, the team found partial shifts potentially caused by a slower orbit around a companion.

These unfinished oscillations were just as likely to swing faster as slower, ruling out the possibility that the change was due to the interaction of the twin stars. If correct, this finding could modify our understanding of stellar formation, especially because scientists now believe binary stars are even more common than single-star systems. It also makes the skies of some exoplanets more exotic, as in the artist’s illustration of a planet in the three-star system Gliese 667 shown above.

No comment yet.
Scooped by Dr. Stefan Gruenwald!

Researcher discovers non-platinum-based halogenated molecules that could kill cancer cells selectively

Researcher discovers non-platinum-based halogenated molecules that could kill cancer cells selectively | Amazing Science |

Researchers have identified new molecules that kill cancer cells while protecting healthy cells and that could be used to treat a variety of different cancers. The research shines a light on what happens to cells at the moment they become cancerous. Professor Qing-Bin Lu, from the University of Waterloo's Faculty of Science, initiated a novel molecular-mechanism-based program to discover a new class of non-platinum-based-halogenated molecules that kill cancer cells, yet prevent healthy cells from being damaged.

Femtosecond time-resolved laser spectroscopy is a technique traditionally applied to study chemical reactions as they occur on a molecular level. The laser takes a series of rapid “snapshots” of molecules as they interact and change structure over time. The technique is part of a potential new field of science developed by Professor Lu called femtomedicine (FMD),  which integrats the ultrafast laser with molecular biology and cell biology.

Professor Lu has applied the tool to understand the molecular mechanisms that cause cancer at the very moment when the DNA becomes damaged. He has also used it to investigate how radiation therapy and chemotherapy using chemical agents, in particular the widely used platinum chemotherapeutic Cisplatin, work in treating a variety of cancers.

“We know DNA damage is the initial step,” said Professor Lu. “With the novel femtomedicine approach we can go back to the very beginning to find out what causes DNA damage in the first place, then mutation, and then cancer.”

By understanding more about the fundamental mechanisms of the diseases, Professor Lu pre-selected molecules most likely to be effective as anti-cancer agents. In this case, he discovered a new family of non-platinum-based molecules similar in structure to Cisplatin but containing no toxic platinum.

Pre-clinical studies with various cultured human cells as well as on rodents show that these new molecules are effective against cervical, breast, ovarian, and lung cancers. Cisplatin, discovered more than 40 years ago, is an important, widely used platinum-based anti-cancer agent. Unfortunately, the inclusion of platinum in the molecule causes serious side effects like neurotoxicity, kidney damage, hearing loss, nausea and vomiting.

“It is extremely rare to discover anti-cancer agents that can selectively kill cancer cells and protect healthy cells, as well as being effective in treating many different types of cancer and having a novel molecular mechanism of action. These candidate drugs should have a high potential to pass through clinical trials and could ultimately save lives”, said Professor Lu.

Professor Lu has already applied for patents on the new family of non-platinum-based-halogenated molecules that he has discovered and hopes to start clinical trials soon.

H. Fai Poon's curator insight, May 13, 11:30 PM

Oncologist's fream come true


Scooped by Dr. Stefan Gruenwald!











No comment yet.
Scooped by Dr. Stefan Gruenwald!








No comment yet.
Scooped by Dr. Stefan Gruenwald!

The fly's neural compass works just like a mammal's












SageRave's curator insight, May 22, 4:50 PM


Scooped by Dr. Stefan Gruenwald!

Cytotoxic T-cells destroying cancer cells captured on film








This is a Fascinating very short film!

Scooped by Dr. Stefan Gruenwald!









Scooped by Dr. Stefan Gruenwald!

World's oldest sperm found and it is gigantic

World's oldest sperm found and it is gigantic | Amazing Science |







Loreto Vargas's curator insight, May 17, 11:01 AM

Amazing and interesting discovery!!

Scooped by Dr. Stefan Gruenwald!

Chinese Search Company Baidu Built a Giant Artificial-Intelligence Supercomputer









LEONARDO WILD's curator insight, May 15, 11:57 AM

Question: What IS intelligence?


Scooped by Dr. Stefan Gruenwald!

A metal composite that floats on water

A metal composite that floats on water | Amazing Science |

Researchers have demonstrated a new metal matrix composite that is so light that it can float on water. A boat made of such lightweight composites will not sink despite damage to its structure. The new material also promises to improve automotive fuel economy because it combines light weight with heat resistance.

Although syntactic foams have been around for many years, this is the first development of a lightweight metal matrix syntactic foam. It is the work of a team of researchers from Deep Springs Technology (DST) and the New York University Polytechnic School of Engineering.


Significant efforts in recent years have focused on developing lightweight polymer matrix composites to replace heavier metal-based components in automobiles and marine vessels. The technology for the new composite is very close to maturation and could be put into prototypes for testing within three years. Amphibious vehicles such as the Ultra Heavy-lift Amphibious Connector (UHAC) being developed by the U.S. Marine Corps can especially benefit from the light weight and high buoyancy offered by the new syntactic foams, the researchers explained.

"This new development of very light metal matrix composites can swing the pendulum back in favor of metallic materials," forecasted Nikhil Gupta, an NYU School of Engineering professor in the Department of Mechanical and Aerospace Engineering and the study's co-author. "The ability of metals to withstand higher temperatures can be a huge advantage for these composites in engine and exhaust components, quite apart from structural parts."

The syntactic foam made by DST and NYU captures the lightness of foams, but adds substantial strength. The secret of this syntactic foam starts with a matrix made of a magnesium alloy, which is then turned into foam by adding strong, lightweight silicon carbide hollow spheres developed and manufactured by DST. A single sphere's shell can withstand pressure of over 25,000 pounds per square inch (PSI) before it ruptures—one hundred times the maximum pressure in a fire hose.

No comment yet.
Scooped by Dr. Stefan Gruenwald!

Scientists Regenerate Bone Tissue Using Only Proteins Secreted by Stem Cells

Scientists Regenerate Bone Tissue Using Only Proteins Secreted by Stem Cells | Amazing Science |

Scientists have discovered a way to regrow bone tissue using the protein signals produced by stem cells. This technology could help treat victims who have experienced major trauma to a limb, like soldiers wounded in combat or casualties of a natural disaster. The new method improves on older therapies by providing a sustainable source for fresh tissue and reducing the risk of tumor formation that can arise with stem cell transplants.


“This proof-of-principle work establishes a novel bone formation therapy that exploits the regenerative potential of stem cells,” says senior author Todd McDevitt, PhD, a senior investigator at the Gladstone Institutes. “With this technique, we can produce new tissue that is completely stem cell-derived and that performs similarly with the gold standard in the field.”

Instead of using stem cells themselves, the scientists extracted the proteins that the cells secrete—such as bone morphogenetic protein (BMP)—in order to harness their regenerative power. To do so, the researchers first treated stem cells with a chemical that helped coax them into early bone cells. Next, they mined the essential factors produced by the cells that send the signal to regenerate new tissue. Finally, the researchers delivered these proteins into mouse muscle tissue to facilitate new bone growth.


“These limitations motivate the need for more consistent and reproducible source material for tissue regeneration,” says Dr. McDevitt, who conducted the research while he was a professor at the Georgia Institute of Technology. “As a renewable resource that is both scalable and consistent in manufacturing, pluripotent stem cells are an ideal solution.”

No comment yet.
Scooped by Dr. Stefan Gruenwald!

Wearables 2015: Defining digital medicine

Wearables 2015: Defining digital medicine | Amazing Science |
Digital medicine is poised to transform biomedical research, clinical practice and the commercial sector. Here we introduce a monthly column from R&D/venture creation firm PureTech tracking digital medicine's emergence.

Technology has already transformed the social fabric of life in the twenty-first century. It is now poised to profoundly influence disease management and healthcare. Beyond the hype of the 'mobile health' and 'wearable technology' movement, the ability to monitor our bodies and continuously gather data about human biology suggests new possibilities for both biomedical research and clinical practice. Just as the Human Genome Project ushered in the age of high-throughput genotyping, the ability to automate, continuously record, analyze and share standardized physiological and biological data augurs the beginning of a new era—that of high-throughput human phenotyping.

These advances are prompting new approaches to research and medicine, but they are also raising questions and posing challenges for existing healthcare delivery systems. How will these technologies alter biomedical research approaches, what types of experimental questions will researchers now be able to ask and what types of training will be needed? Will the ability to digitize individual characteristics and communicate by mobile technology empower patients and enable the modification of disease-promoting behaviors; at the same time, will it threaten patient privacy? Will doctors be prescribing US Food and Drug Administration (FDA)-cleared apps on a regular basis, not just to monitor and manage chronic disease but also to preempt acute disease episodes? Will the shift in the balance between disease treatment and early intervention have a broad economic impact on the healthcare system? How will the emergence of these new technologies reshape the healthcare industry and its underlying business models? What will be the defining characteristics of 'winning' products and companies?

These are just some of the questions we plan to ask over the coming months. In the meantime, we introduce here some of the key themes shaping R&D in the digital medicine field and focus on what they might mean for the biopharmaceutical and diagnostic/device industries.

Risto Suoknuuti's curator insight, May 17, 4:23 AM

Man made machines for mans use. Systems simplyfies after getting complex. This is the rule in the winning game.

Ed Crowley's curator insight, May 17, 8:30 AM

Wearable medical technology is quickly changing the potential for health research, and with IoT, health management. 

Be-Bound®'s curator insight, May 18, 9:54 AM

And this is just the beginning ! 

Scooped by Dr. Stefan Gruenwald!

Astrophysicists detect weather patterns on six different exoplanets

Astrophysicists detect weather patterns on six different exoplanets | Amazing Science |

Using sensitive observations from the Kepler space telescope, the researchers have uncovered evidence of daily weather cycles on six extra-solar planets seen to exhibit different phases. Such phase variations occur as different portions of these planets reflect light from their stars, similar to the way our own moon cycles though different phases.

Among the findings are indications of cloudy mornings on four of them and hot, clear afternoons on two others. "We determined the weather on these alien worlds by measuring changes as the planets circle their host stars, and identifying the day-night cycle," said Lisa Esteves, a PhD candidate in the Department of Astronomy & Astrophysics at the University of Toronto, and lead author of the study published today in The Astrophysical Journal.

"We traced each of them going through a cycle of phases in which different portions of the planet are illuminated by its star, from fully lit to completely dark," said Esteves.

Because the planets are very near to their stars, they are expected to rotate counter-clockwise - just as the majority of objects in our solar system do - with the right side moving in the direction of each planet's orbit. This causes an eastward movement of the planet's surface and therefore an eastward circulation of atmospheric winds. As a result, clouds that form on the planet's night side, where temperatures are cooler while it faces away from its host star, would be blown to the planet's morning side.

"As the winds continue to transport the clouds to the day side, they heat up and dissipate, leaving the afternoon sky cloud-free," said Esteves. "These winds also push the hot air eastward from the meridian, where it is the middle of the day, resulting in higher temperatures in the afternoon."

For four of the planets, the researchers saw excess brightness in the Kepler data that corresponds to when the morning side is visible. For the other two, they saw an excess when the evening side is visible. "By comparing the planets' previously determined temperatures to the phase cycle measurements provided by Kepler, we found that the excess brightness on the morning side is most likely generated by reflected starlight," said Esteves. "These four planets are not hot enough to generate this excess light through thermal emission.

"The excess light seen on the two very hot planets can be explained by thermal emission," said Esteves. "A likely explanation is that on these two planets, the winds are moving heat towards the evening side, resulting in the excess brightness."

The Kepler telescope was the ideal instrument for the study of exoplanet phase variations. The very precise measurements it provided and the vast amount of data it collected allowed astronomers to measure the tiny signals from these distant worlds. Most of the planets examined in this study are very hot and large, with temperatures greater than 1600 degrees Celsius and sizes comparable to Jupiter - conditions far from hospitable to life but excellent for phase measurements.

No comment yet.
Scooped by Dr. Stefan Gruenwald!

Single-electron fractionalization (dividing the electron into smaller "charge pulses") observed on picosecond scale

Single-electron fractionalization (dividing the electron into smaller "charge pulses") observed on picosecond scale | Amazing Science |

Coulomb interaction has a striking effect on electronic propagation in one-dimensional conductors. The interaction of an elementary excitation with neighboring conductors favors the emergence of collective modes, which eventually leads to the destruction of the Landau quasiparticle. In this process, an injected electron tends to fractionalize into separated pulses carrying a fraction of the electron charge. Here, a team of physicists now use two-particle interferences in the electronic analog of the Hong-Ou-Mandel experiment in a quantum Hall conductor at filling factor 2 to probe the fate of a single electron emitted in the outer edge channel and interacting with the inner one. By studying both channels, they analyze the propagation of the single electron and the generation of interaction-induced collective excitations in the inner channel. These complementary pieces of information reveal the fractionalization process in the time domain and establish its relevance for the destruction of the quasiparticle, which degrades into the collective modes.

No comment yet.
Scooped by Dr. Stefan Gruenwald!

Intense thunderclouds produce haze of antimatter photons that do not fit any known source of antiparticles

Intense thunderclouds produce haze of antimatter photons that do not fit any known source of antiparticles | Amazing Science |

When Joseph Dwyer’s aeroplane took a wrong turn into a thundercloud, the mistake paid off: the atmospheric physicist flew not only through a frightening storm but also into an unexpected — and mysterious — haze of antimatter. Although powerful storms have been known to produce positrons — the antimatter versions of electrons — the antimatter observed by Dwyer and his team cannot be explained by any known processes, they say. “This was so strange that we sat on this observation for several years,” says Dwyer, who is at the University of New Hampshire in Durham.

The flight took place six years ago, but the team is only now reporting the result (J. R. Dwyer et al. J. Plasma Phys.; in the press). “The observation is a puzzle,” says Michael Briggs, a physicist at the NASA Marshall Space Flight Center in Huntsville, Alabama, who was not involved in the report.

A key feature of antimatter is that when a particle of it makes contact with its ordinary-matter counterpart, both are instantly transformed into other particles in a process known as annihilation. This makes antimatter exceedingly rare. However, it has long been known that positrons are produced by the decay of radioactive atoms and by astrophysical phenomena, such as cosmic rays plunging into the atmosphere from outer space. In the past decade, research by Dwyer and others has shown that storms also produce positrons, as well as highly energetic photons, or γ-rays.

It was to study such atmospheric γ-rays that Dwyer, then at the Florida Institute of Technology in Melbourne, fitted a particle detector on a Gulfstream V, a type of jet plane typically used by business executives. On 21 August 2009, the pilots turned towards what looked, from its radar profile, to be the Georgia coast. “Instead, it was a line of thunderstorms — and we were flying right through it,” Dwyer says. The plane rolled violently back and forth and plunged suddenly downwards. “I really thought I was going to die.”

During those frightening minutes, the detector picked up three spikes in γ-rays at an energy of 511 kiloelectronvolts, the signature of a positron annihilating with an electron. Each γ-ray spike lasted about one-fifth of a second, Dwyer and his collaborators say, and was accompanied by some γ-rays of slightly lower energy. The team concluded that those γ-rays had lost energy as a result of travelling some distance and calculated that a short-lived cloud of positrons, 1–2 kilometres across, had surrounded the aircraft. But working out what could have produced such a cloud has proved hard. “We tried for five years to model the production of the positrons,” says Dwyer.

Electrons discharging from charged clouds accelerate to close to the speed of light, and can produce highly energetic γ-rays, which in turn can generate an electron–positron pair when they hit an atomic nucleus. But the team did not detect enough γ-rays with sufficient energy to do this.

No comment yet.