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iceworm

Unlocking secrets of the ice worm

The ice worm is one of the largest organisms that spends its entire life in ice and Washington State University scientist Scott Hotaling is one of the only people on the planet studying it.

He is the author of a new paper that shows ice worms in the interior of British Columbia have evolved into what may be a genetically distinct species from Alaskan ice worms.

Hotaling and colleagues also identified an ice worm on Vancouver Island that is closely related to a separate population of ice worms located 1,200 miles away in southern Alaska. The researchers believe the genetic intermingling is the result of birds eating the glacier-bound worms (or their eggs) at one location and then dropping them off at another as they migrate up and down the west coast.

“If you are a worm isolated on a mountaintop glacier, the expectation is you aren’t going anywhere,” said Hotaling, a postdoctoral biology researcher. “But lo and behold, we found this one ice worm on Vancouver Island that is super closely related to ice worms in southern Alaska. The only reasonable explanation we can think of to explain this is birds.”

Super cool organism

The ice worm resembles the common earthworm but is smaller and darker in color.  What sets the ice worm apart from other members of the Mesenchytraeus genus is its ability to live its entire life in glacial ice.

Millions, perhaps hundreds of millions, of ice worms can be seen wriggling to the top of glaciers from the Chugach Mountains in southeast Alaska to the Cascade Volcanoes of Washington and Oregon during the summer months. In the fall and winter, ice worms subsist deep beneath the surface of glaciers where temperatures stay around freezing.

Scott Hotaling

Hotaling’s interest in ice worms began back in 2009 while he was working as a mountaineering ranger on the high elevation slopes of Mt. Rainer. He was climbing at three in the morning when he noticed a lot of small, black worms crawling around on the surface of a glacier.

“I wasn’t even a biology undergraduate yet but I remember being so fascinated by the fact that there is this worm that can live in a glacier,” he said. “It is not a place where we think of life being able to flourish and these things can be present at like 200 per sq. meter, so dense you can’t walk without stepping in them.”

Hotaling eventually went back to school and earned a PhD in biology at the University of Kentucky where he studied how climate change is affecting mountain biodiversity.

In the summer of 2017, he finally got the opportunity to circle back and do some research on the ice worm when he arrived in Pullman to start a postdoc position in the laboratory of Associate Professor Joanna Kelley, senior author of the study who specializes in evolutionary genomics and extremophile lifeforms.

“In the Kelley lab, we study organisms that have evolved to live in places that are inhospitable to pretty much everything else,” Hotaling said. “Determining the evolutionary mechanisms that enable something like an ice worm to live in a glacier or bacteria to live in a Yellowstone hot spring is a really exciting way to learn about what is possible at the bounds of evolution. That’s where we are working now, understanding the evolution of ice worms.”

In the study

Hotaling and colleagues extracted and sequenced DNA from 59 ice worms collected from nine glaciers across most of their geographical range. Their analysis revealed a genetic divergence between populations of ice worms that are north and west and south and east of the Coast Mountains of British Columbia.

The researchers predict that this deeper split into two genetically distinct ice worm groups occurred as a result of glacial ice sheets contracting around a few hundred thousand years ago, isolating worms in the Pacific Northwest from their counterparts in Alaska.

The most surprising finding of the study was the discovery of a single ice worm on Vancouver Island that was closely related to a population of ice worms 1,200 miles away in Alaska.

“At first we thought there has to be some kind of error in the analysis or prep methods but upon further investigation we confirmed our initial results,” Hotaling said. “These are worms isolated on mountain tops and there is no explanation for how they covered that gap than on, or perhaps within, migrating birds.”

A Gray-Crowned Rosy Finch eating ice worms.
A Gray-Crowned Rosy Finch eating ice worms on a glacier. Photo by Scott Hotaling

The research illuminates an important relationship between two of the few large organisms that inhabit North America’s high elevation alpine ecosystems, the ice worm and the Gray-Crowned Rosy Finch, one of North America’s highest elevation nesting birds.

“We knew that ice worms were an important source of food for the birds but we didn’t know until now that the birds are also likely very important for the ice worms,” Hotaling said. “If you are super isolated like an ice worm, you could easily become inbred. But if birds are bringing little bits of new diversity to your mountaintop glacier that could be really good for you.”

Hotaling and Kelley’s study was published this month in Proceedings B of the Royal Society of Publishing.

Materials provided by Washington State University

MIT Nanoemulsions

“Nanoemulsion” gels offer new way to deliver drugs through the skin

MIT chemical engineers have devised a new way to create very tiny droplets of one liquid suspended within another liquid, known as nanoemulsion. Such emulsions are similar to the mixture that forms when you shake an oil-and-vinegar salad dressing, but with much smaller droplets. Their tiny size allows them to remain stable for relatively long periods of time.

The researchers also found a way to easily convert the liquid nanoemulsion to a gel when they reach body temperature (37 degrees Celsius), which could be useful for developing materials that can deliver medication when rubbed on the skin or injected into the body.

“The pharmaceutical industry is hugely interested in nanoemulsions as a way of delivering small molecule therapeutics. That could be topically, through ingestion, or by spraying into the nose, because once you start getting into the size range of hundreds of nanometers you can permeate much more effectively into the skin,” says Patrick Doyle, the Robert T. Haslam Professor of Chemical Engineering and the senior author of the study.

In their new study, which appears in the June 21 issue of Nature Communications, the researchers created nanoemulsions that were stable for more than a year. To demonstrate the emulsions’ potential usefulness for delivering drugs, the researchers showed that they could incorporate ibuprofen into the droplets.

Seyed Meysam Hashemnejad, a former MIT postdoc, is the first author of the study. Other authors include former postdoc Abu Zayed Badruddoza, L’Oréal senior scientist Brady Zarket, and former MIT summer research intern Carlos Ricardo Castaneda.

Energy reduction

One of the easiest ways to create an emulsion is to add energy — by shaking your salad dressing, for example, or using a homogenizer to break down fat globules in milk. The more energy that goes in, the smaller the droplets, and the more stable they are.

Nanoemulsions, which contain droplets with a diameter 200 nanometers or smaller, are desirable not only because they are more stable, but they also have a higher ratio of surface area to volume, which allows them to carry larger payloads of active ingredients such as drugs or sunscreens.

Over the past few years, Doyle’s lab has been working on lower-energy strategies for making nanoemulsions, which could make the process easier to adapt for large-scale industrial manufacturing.

Detergent-like chemicals called surfactants can speed up the formation of emulsions, but many of the surfactants that have previously been used for creating nanoemulsions are not FDA-approved for use in humans. Doyle and his students chose two surfactants that are uncharged, which makes them less likely to irritate the skin, and are already FDA-approved as food or cosmetic additives. They also added a small amount of polyethylene glycol (PEG), a biocompatible polymer used for drug delivery that helps the solution to form even smaller droplets, down to about 50 nanometers in diameter.

“With this approach, you don’t have to put in much energy at all,” Doyle says. “In fact, a slow stirring bar almost spontaneously creates these super small emulsions.”

Active ingredients can be mixed into the oil phase before the emulsion is formed, so they end up loaded into the droplets of the emulsion.

Once they had developed a low-energy way to create nanoemulsions, using nontoxic ingredients, the researchers added a step that would allow the emulsions to be easily converted to gels when they reach body temperature. They achieved this by incorporating heat-sensitive polymers called poloxamers, or Pluronics, which are already FDA-approved and used in some drugs and cosmetics.

Pluronics contain three “blocks” of polymers: The outer two regions are hydrophilic, while the middle region is slightly hydrophobic. At room temperature, these molecules dissolve in water but do not interact much with the droplets that form the emulsion. However, when heated, the hydrophobic regions attach to the droplets, forcing them to pack together more tightly and creating a jelly-like solid. This process happens within seconds of heating the emulsion to the necessary temperature.

MIT chemical engineers have devised a way to convert liquid nanoemulsions into solid gels. These gels (red) form almost instantaneously when drops of the liquid emulsion enter warm water.

MIT chemical engineers have devised a way to convert liquid nanoemulsions into solid gels. These gels (red) form almost instantaneously when drops of the liquid emulsion enter warm water.

Tunable properties

The researchers found that they could tune the properties of the gels, including the temperature at which the material becomes a gel, by changing the size of the emulsion droplets and the concentration and structure of the Pluronics that they added to the emulsion. They can also alter traits such as elasticity and yield stress, which is a measure of how much force is needed to spread the gel.

Doyle is now exploring ways to incorporate a variety of active pharmaceutical ingredients into this type of gel. Such products could be useful for delivering topical medications to help heal burns or other types of injuries, or could be injected to form a “drug depot” that would solidify inside the body and release drugs over an extended period of time. These droplets could also be made small enough that they could be used in nasal sprays for delivering inhalable drugs, Doyle says.

For cosmetic applications, this approach could be used to create moisturizers or other products that are more shelf-stable and feel smoother on the skin.

Materials provided by Massachusetts Institute of Technology

Paper sensor

A paper sensor detects food spoilage

Worldwide, nearly a third of all food is wasted. Much of it is still safe to eat, but consumers throw it away because it’s close to or beyond its printed expiration date. That waste could be mitigated if food were packaged with a sensor that monitored its spoilage in real time. But such a device would need to be low cost, easy to produce, and unambiguous to read. Toward that end, Firat Güder of Imperial College London in the UK and his colleagues have designed a paper sensor that detects the gases emitted during food decomposition.

At typical levels of humidity, a paper surface becomes coated with a thin layer of water, which absorbs water-soluble gases from the environment (right panel of the figure). The gas molecules contribute positive and negative ions that change the water’s electrical conductivity by an amount proportional to the gases’ concentration. To access that electrical information, Güder and his team drew electrodes on paper (left panel) with commercial carbon ink and a ballpoint pen. The device’s conductivity was sensitive to the concentration of ammonia and trimethylamine (TMA), two water-soluble gases associated with food spoilage.

Güder and his colleagues used the sensor to monitor the spoilage of a chicken breast and codfish at room temperature and codfish in the fridge. As the meats decomposed, they produced ammonia, TMA, and dimethylamine, and the sensor’s response increased by up to a factor of 10.

The team integrated the paper sensor into a commercial near-field-communication tag so it could talk to a smartphone. Below a threshold amount of ammonia, the sensor responded to the smartphone; above the threshold, the tag was unresponsive. In a practical application of the sensor, a manufacturer would set the threshold to an appropriate concentration for the product, and the consumer would check the freshness with their phone.

The sensor does have a couple of drawbacks. Its response depends strongly on humidity and doesn’t distinguish among species of water-soluble gases. But the humidity is stable in some environments, such as packaged food, or can be monitored separately, and chemical additives are able to tune water’s sensitivity for specific gases. (G. Barandun et al., ACS Sens., 2019, doi:10.1021/acssensors.9b00555; thumbnail photo credit: Lance Cheung/USDA.

Materials provided by American Institute of Physics

Carbon Escape

An escape route for carbon

As many of us may recall from grade school science class, the Earth’s carbon cycle goes something like this: As plants take up carbon dioxide and convert it into organic carbon, they release oxygen back into the air. Complex life forms such as ourselves breathe in this oxygen and respire carbon dioxide. When microbes eat away at decaying plants, they also consume the carbon within, which they convert and release back into the atmosphere as carbon dioxide. And so the cycle continues.

The vast majority of the planet’s carbon loops perpetually through this cycle, driven by photosynthesis and respiration. There is, however, a tiny fraction of organic carbon that is continually escaping through a “leak” in the cycle, the cause of which is largely unknown. Scientists do know that, through this leak, some minute amount of carbon is constantly locked away and preserved in the form of rock for hundreds of millions of years.

Now, researchers from MIT and elsewhere have found evidence for what may be responsible for carbon’s slow and steady escape route.

In a paper published today in the journal Nature, the team reports that organic carbon is leaking out of the carbon cycle mainly due to a mechanism they call “mineral protection.” In this process, carbon, in the form of decomposed bits of plant and phytoplankton material, gloms onto particles of clay and other minerals, for instance at the bottom of a river or ocean, and is preserved in the form of sediments and, ultimately, rock.

Mineral protection may also explain why there is oxygen on Earth in the first place: If something causes carbon to leak out of the carbon cycle, this leaves more oxygen to accumulate in the atmosphere.

“Fundamentally, this tiny leak is one reason why we exist,” says Daniel Rothman, professor of geophysics in MIT’s Department of Earth, Atmospheric and Planetary Sciences. “It’s what allows oxygen to accumulate over geologic time, and it’s why aerobic organisms evolved, and it has everything to do with the history of life on the planet.”

Rothman’s co-authors on the paper include Jordon Hemingway, who led the work as a graduate student at MIT and the Woods Hole Oceanographic Institution and is now a postdoc at Harvard University, along with Katherine Grant, Sarah Rosengard, Timothy Eglinton, Louis Derry, and Valier Galy.

Burning dirt

Scientists have entertained two main possibilities for how carbon has been leaking out of the Earth’s carbon cycle. The first has to do with “selectivity,” the idea that some types of organic matter, due to their molecular makeup, may be harder to break down than others. Based on this idea, the carbon that is not consumed, and therefore leaks out, has been “selected” to do so, based on the initial organic matter’s molecular structure.

The second possibility involves “accessibility,” the notion that some organic matter leaks out of the carbon cycle because it has been made inaccessible for consumption via some secondary process. Some scientists believe that secondary process could be mineral protection — interactions between organic carbon and clay-based minerals that bind the two together in an inaccessible, unconsumable form.

To test which of these mechanisms better explains Earth’s carbon leak, Hemingway analyzed sediment samples collected from around the world, each containing organic matter and minerals from a range of river and coastal environments. If mineral preservation is indeed responsible for locking away and preserving carbon over geologic timescales, Hemingway hypothesized that organic carbon bound with clay minerals should last longer in the environment compared with unbound carbon, resisting degradation by foraging microbes, or even other forces such as extreme heat.

The researchers tested this idea by burning each sediment sample and measuring the amount and type of organic carbon that remained as they heated the sample at progressively higher temperatures. They did so using a device that Hemingway developed as part of his PhD thesis.

“It’s been hypothesized that organic matter that sticks to mineral surfaces will stick around longer in the environment,” Hemingway says. “But there was never a tool to directly quantify that.”

“Beating up a natural process”

In the end, they found the organic matter that lasted the longest, and withstood the highest temperatures, was bound to clay minerals. Importantly, in a finding that went against the idea of selectivity, it didn’t matter what the molecular structure of that organic matter was — as long as it was bound to clay, it was preserved.

The results point to accessibility, and mineral preservation in particular, as the main mechanism for Earth’s carbon leak. In other words, all around the world, clay minerals are slowly and steadily drawing down tiny amounts of carbon, and storing it away for thousands of years.

“It’s this clay-bound protection that seems to be the mechanism, and it seems to be a globally coherent phenomenon,” Hemingways says. “It’s a slow leak happening all the time, everywhere. And when you integrate that over geologic timescales, it becomes a really important sink of carbon.”

The researchers believe mineral protection has made it possible for vast reservoirs of carbon to be buried and stored in the Earth, some of which has been pressed and heated into petroleum over millions of years. At the Earth’s geologic pace, this carbon preserved in rocks eventually resurfaces through mountain uplift and gradually erodes, releasing carbon dioxide back into the atmosphere ever so slowly.

“What we do today with fossil fuel burning is speeding up this natural process,” Rothman says. “We’re getting it out of the ground and burning it right away, and we’re changing the rate at which the carbon that was leaked out is being returned to the system, by a couple orders of magnitude.”

Could mineral preservation somehow be harnessed to sequester even more carbon, in an effort to mitigate fossil-fuel-induced climate change?

“If we magically had the ability to take a fraction of organic matter in rivers or oceans and attach it to a mineral to hold onto it for 1,000 years, it could have some advantages,” Rothman says. “That’s not the focus of this study. But the longer soils can lock up organic matter, the slower their return to the atmosphere. You can imagine if you could slow that return process down just a little bit, it could make a big difference over 10 to 100 years.”

Materials provided by Massachusetts Institute of Technology

Bee can relate symbols to numbers

Bees can link symbols to numbers: study

Researchers have trained honeybees to match a character to a specific quantity, revealing they are able to learn that a symbol represents a numerical amount.

It’s a finding that sheds new light on how numerical abilities may have evolved over millennia and even opens new possibilities for communication between humans and other species.

The discovery, from the same Australian-French team that found bees get the concept of zero and can do simple arithmetic, also points to new approaches for bio-inspired computing that can replicate the brain’s highly efficient approach to processing.

The RMIT University-led study is published today in Proceedings of the Royal Society B.

Associate Professor Adrian Dyer said while humans were the only species to have developed systems to represent numbers, like the Arabic numerals we use each day, the research shows the concept can be grasped by brains far smaller than ours.

“We take it for granted once we’ve learned our numbers as children, but being able to recognise what ‘4’ represents actually requires a sophisticated level of cognitive ability,” Dyer said.

“Studies have shown primates and birds can also learn to link symbols with numbers, but this is the first time we’ve seen this in insects.

“Humans have over 86 billion neurons in our brains, bees have less than a million, and we’re separated by over 600 million years of evolution.

“But if bees have the capacity to learn something as complex as a human-made symbolic language, this opens up exciting new pathways for future communication across species.”

Mini brains, maximum potential: what the bees learned

Studies have shown that a number of non-human animals have been able to learn that symbols can represent numbers, including pigeons, parrots, chimpanzees and monkeys.

Some of their feats have been impressive – chimpanzees were taught Arabic numbers and could order them correctly, while an African grey parrot called Alex was able to learn the names of numbers and could sum the quantities.

The new study for the first time shows that this complex cognitive capacity is not restricted to vertebrates.

The humble honeybee: A million neurons of pure brain power.

The humble honeybee: A million neurons of pure brain power. (Credit: RMIT University)

The humble honeybee: A million neurons of pure brain power.

The bee experiment was conducted by Dr Scarlett Howard, formerly a PhD researcher in the Bio-Inspired Digital Sensing-Lab (BIDS-Lab) at RMIT and now a fellow at the Research Center on Animal Cognition, University of Toulouse III – Paul Sabatier, CNRS.

In a Y-shaped maze, individual bees were trained to correctly match a character with a number of elements.

They were then tested on whether they could apply their new knowledge to match the character to various elements of the same quantity (in the same way that ‘2’ can represent two bananas, two trees or two hats).

A second group was trained in the opposite approach, matching a number of elements with a character.

While both could grasp their specific training, the different groups were unable to reverse the association and work out what to do when tested with the opposite (character-to-number or number-to-character).

“This suggests that number processing and understanding of symbols happens in different regions in bee brains, similar to the way separate processing happens in the human brain,” Howard said.

“Our results show honeybees are not at the same level as the animals that have been able to learn symbols as numbers and perform complex tasks.

“But the results have implications for what we know about learning, reversing tasks, and how the brain creates connections and associations between concepts.

“Discovering how such complex numerical skills can be grasped by miniature brains will help us understand how mathematical and cultural thinking evolved in humans, and possibly, other animals.”

Details of the experimental set up used to train and test the bees.

The bees were trained and tested in a Y-shaped maze. (Credit: RMIT University)

The bees were trained and tested in a Y-shaped maze.

Studying insect brains offers intriguing possibilities for the future design of highly efficient computing systems, Dyer said.

“When we’re looking for solutions to complex problems, we often find that nature has already done the job far more elegantly and efficiently,” he said.

“Understanding how tiny bee brains manage information opens paths to bio-inspired solutions that use a fraction of the power of conventional processing systems.”

Symbolic representation of numerosity by honeybees (Apis mellifera): Matching characters to small quantities – with co-authors Aurore Avarguès-Weber (University of Toulouse), Jair Garcia (School of Media and Communication, RMIT) and Professor Andrew Greentree (ARC Centre of Excellence for Nanoscale Biophotonics, RMIT) – is published in Proceedings of the Royal Society B (DOI: 10.1098/rspb.2019.0238).

Materials provided by RMIT University

Porcine EPSC colony

HKU Discovers Stem Cell Breakthrough Offers New Avenue for Advancing Research

A new approach to deriving stem cells that was led and developed by scholars from LKS Faculty of Medicine of The University of Hong Kong (HKUMed), in collaboration with scientists from the Wellcome Sanger Institute in Cambridge, UK and the Friedrich-Loeffler-Institut in Germany, offers groundbreaking potential for studying embryonic development and producing translational research in genomics and regenerative medicine, biotechnology and agriculture. The findings were published in Nature Cell Biology.

The Expanded Potential Stem Cells (EPSCs) of both porcine (pig) and human have been established. The porcine EPSCs are particularly important because this is the first time scientists have been able to derive stem cells from early pig embryos. Domestic pigs have great potential for biomedical research because of their similarity to human genetics, anatomy and physiology (such as organ size). Being able to genetically-modify pig stem cells will also be beneficial for animal health and food production. Human EPSCs are expected to provide a new cell source for studying human development and regenerative medicine.

Professor Pengtao Liu of the School of Biomedical Sciences and Stem Cell and Regenerative Medicine Consortium, HKUMed, who leads the research, said: “Scientists have been attempting to derive porcine embryonic stem cells for decades without much success. With our EPSC technology, we have now successfully derived and characterised stem cells from porcine preimplantation embryos. We have also established similar human stem cells. Our study represents a major advance in stem cell research.”

The key characteristic of EPSCs is that they are derived from pre-implantation embryos of very early developmental stages. Until now, embryonic stem cells, in general, are established from pre-implantation embryos made up of at least dozens of cells that are called blastocysts. In the embryos earlier than the blastocysts stage, cells are less differentiated and have potential to develop into more kinds of cells. EPSCs have the potential to produce all types of cell and thus have totipotency features.

Professor Liu’s group has so far established EPSCs from mouse, pig and human. These new stem cells across species are molecularly similar and amenable to multiple rounds of genome-editing. Besides their capacity to produce all types of cell found in our body and are useful for studying human disease and regenerative medicine, human EPSCs can produce large numbers of placenta cells, called trophoblasts, which offer new opportunities to investigate pregnancy complications such as pre-eclampsia and miscarriages.

“These EPSC stem cells possess developmental potency that is not generally seen in conventional or standard embryonic or induced pluripotent stem cells. They have the potential to produce all embryonic and extra-embryonic cell lines – including those in the placenta and yolk sac, turning back the development clock to the very earliest cell type. These cells will enable researchers to study early embryonic development, miscarriage and developmental disorders,” said Dr Xuefui Gao, who was the first author of the Nature Cell Biology paper.

Professor Liu provided the inspiration for this approach after noticing the difficulties scientists faced in developing stem cell lines for mammals beyond some rodents and primates. The practice of using blastocysts for deriving stem cells dates back to the 1970s and 1980s when the first study to derive stem cells was carried out and the technology and understanding of molecular events were much more limited than today. Blastocysts have been the norm ever since, but the HKU scientists thought that earlier intervention might offer a greater chance of success.

“The earlier embryonic developmental stages that we get embryonic stem cells, the less diversity there might be among mammalian species, the higher chance that the EPSC technology works for more mammalian species. Our idea was to try to investigate conditions that could allow us to capture and derive stem cells from the very early embryos of different species – when they are like a blank sheet of paper – and remarkably it works,” said Professor Pengtao Liu.

The first breakthrough from Professor Liu’s research group came with mice in 2017, when key molecular pathways that drive cell lineage differentiation were targeted. The most recent study on human and porcine EPSCs suggests that this approach might be possible with mammals that hitherto had been elusive to stem cell researchers.

Dr Monika Nowak-Imialek of the Friedrich-Loeffler-Institut (FLI), a co-first author of the paper, said: “Our porcine EPSCs isolated from pig embryos are the first well-characterised porcine cell lines worldwide. EPSC’s great potential to develop into any type of cell provides important implications for developmental biology, regenerative medicine, organ transplantation, disease modeling, animal health, agriculture and biotechnology.”

Building on this work, the HKUMed researchers are continuing to push the EPSC technology and are collaborating with other research groups. “We are excited that these new stem cells are expected to have broad applications in basic and translational research in the near future,” said Professor Pengtao Liu.

About the research team

The research was led and conducted by Professor Pengtao Liu’s laboratory at HKUMed, in collaboration with Professor William Yeung of the Department of Obstetrics and Gynaecology, HKUMed; together with Professor Heiner Niemann, Director Emeritus of Friedrich-Loeffler-Institut (FLI) and Dr. Monika Nowak-Imialek of FLI; Professor Sarah Teichmann and Dr Xi Chen of the Wellcome Sanger Institute in Cambridge, UK; Professor Asif Ahmed of Aston University, UK; and several collaborating research laboratories in Mainland China. This study was supported by HKUMed and HKU internal funding and by the Wellcome Sanger Institute.

Materials provided by University of Hong Kong

PPPL physicist Lan Gao

Physicists create stable, strongly magnetized plasma jet in laboratory

When you peer into the night sky, much of what you see is plasma, a soupy amalgam of ultra-hot atomic particles. Studying plasma in the stars and various forms in outer space requires a telescope, but scientists can recreate it in the laboratory to examine it more closely.

Now, a team of scientists led by physicists Lan Gao of the U.S. Department of Energy’s (DOE) Princeton Plasma Physics Laboratory (PPPL) and Edison Liang of Rice University, has for the first time created a particular form of coherent and magnetized plasma jet that could deepen the understanding of the workings of much larger jets that stream from newborn stars and possibly black holes — stellar objects so massive that they trap light and warp both space and time.

“We are now creating stable, supersonic, and strongly magnetized plasma jets in a laboratory that might allow us to study astrophysical objects light years away,” said astrophysicist Liang, co-author of the paper reporting the results in The Astrophysical Journal Letters.

The team created the jets using the OMEGA Laser Facility at the University of Rochester’s Laboratory for Laser Energetics (LLE). The researchers aimed 20 of OMEGA’s individual laser beams into a ring-shaped area on a plastic target. Each laser created a tiny puff of plasma; as the puffs expanded, they put pressure on the inner region of the ring. That pressure then squeezed out a plasma jet reaching over four millimeters in length and created a magnetic field that had a strength of over 100 tesla.

“This is the first step in studying plasma jets in a laboratory,” said Gao, who was the primary author of the paper. “I’m excited because we not only created a jet. We also successfully used advanced diagnostics on OMEGA to confirm the jet’s formation and characterize its properties.”

The diagnostic tools, developed with teams from LLE and the Massachusetts Institute of Technology (MIT), measured the jet’s density, temperature, length, how well it stayed together as it grew through space, and the shape of the magnetic field around it. The measurements help scientists determine how the laboratory phenomena compare to jets in outer space. They also provide a baseline that scientists can tinker with to observe how the plasma behaves under different conditions.

“This is groundbreaking research because no other team has successfully launched a supersonic, narrowly beamed jet that carries such a strong magnetic field, extending to significant distances,” said Liang. “This is the first time that scientists have demonstrated that the magnetic field does not just wrap around the jet, but also extends parallel to the jet’s axis,” he said.

The researchers hope to expand their research with larger laser facilities and investigate other types of phenomena. “The next step involves seeing whether an external magnetic field could make the jet longer and more collimated,” Gao said.

“We would also like to replicate the experiment using the National Ignition Facility at Lawrence Livermore National Laboratory, which has 192 laser beams, half of which could be used to create our plasma ring. It would have a larger radius and thus produce a longer jet than that produced using OMEGA. This process would help us figure out under which conditions the plasma jet is strongest.”

The team included scientists from PPPL, Rice, LLE, MIT, and the University of Chicago. The research was supported by the DOE’s National Nuclear Security Administration, the National Science Foundation, and Los Alamos National Laboratory. Computer simulations were performed on the Extreme Science and Engineering Discovery Environment (XSEDE), a collaborative partnership of 19 institutions, and the Argonne Leadership Computing Facility, a DOE Office of Science user facility.

Materials provided by Princeton Plasma Physics Laboratory