What scientists found after sifting through dust in the solar system

In this illustration, several dust rings circle the sun. These rings form when planets' gravities tug dust grains into orbit around the sun. Recently, scientists have detected a dust ring at Mercury's orbit. Others hypothesize the source of Venus' dust ring is a group of never-before-detected co-orbital asteroids.

Just as dust gathers in corners and along bookshelves in our homes, dust piles up in space too. But when the dust settles in the solar system, it's often in rings. Several dust rings circle the Sun. The rings trace the orbits of planets, whose gravity tugs dust into place around the Sun, as it drifts by on its way to the center of the solar system.

The dust consists of crushed-up remains from the formation of the solar system, some 4.6 billion years ago -- rubble from asteroid collisions or crumbs from blazing comets. Dust is dispersed throughout the entire solar system, but it collects at grainy rings overlying the orbits of Earth and Venus, rings that can be seen with telescopes on Earth. By studying this dust -- what it's made of, where it comes from, and how it moves through space -- scientists seek clues to understanding the birth of planets and the composition of all that we see in the solar system.

Two recent studies report new discoveries of dust rings in the inner solar system. One study uses NASA data to outline evidence for a dust ring around the Sun at Mercury's orbit. A second study from NASA identifies the likely source of the dust ring at Venus' orbit: a group of never-before-detected asteroids co-orbiting with the planet.

"It's not every day you get to discover something new in the inner solar system," said Marc Kuchner, an author on the Venus study and astrophysicist at NASA's Goddard Space Flight Center in Greenbelt, Maryland. "This is right in our neighborhood."

Another Ring Around the Sun

Guillermo Stenborg and Russell Howard, both solar scientists at the Naval Research Laboratory in Washington, D.C., did not set out to find a dust ring. "We found it by chance," Stenborg said, laughing. The scientists summarized their findings in a paper published in The Astrophysical Journal on Nov. 21, 2018.

They describe evidence of a fine haze of cosmic dust over Mercury's orbit, forming a ring some 9.3 million miles wide. Mercury -- 3,030 miles wide, just big enough for the continental United States to stretch across -- wades through this vast dust trail as it circles the Sun.

Ironically, the two scientists stumbled upon the dust ring while searching for evidence of a dust-free region close to the Sun. At some distance from the Sun, according to a decades-old prediction, the star's mighty heat should vaporize dust, sweeping clean an entire stretch of space. Knowing where this boundary is can tell scientists about the composition of the dust itself, and hint at how planets formed in the young solar system.

So far, no evidence has been found of dust-free space, but that's partly because it would be difficult to detect from Earth. No matter how scientists look from Earth, all the dust in between us and the Sun gets in the way, tricking them into thinking perhaps space near the Sun is dustier than it really is.

Stenborg and Howard figured they could work around this problem by building a model based on pictures of interplanetary space from NASA's STEREO satellite -- short for Solar and Terrestrial Relations Observatory.

Ultimately, the two wanted to test their new model in preparation for NASA's Parker Solar Probe, which is currently flying a highly elliptic orbit around the Sun, swinging closer and closer to the star over the next seven years. They wanted to apply their technique to the images Parker will send back to Earth and see how dust near the Sun behaves.

Scientists have never worked with data collected in this unexplored territory, so close to the Sun. Models like Stenborg and Howard's provide crucial context for understanding Parker Solar Probe's observations, as well as hinting at what kind of space environment the spacecraft will find itself in -- sooty or sparkling clean.

Two kinds of light show up in STEREO images: light from the Sun's blazing outer atmosphere -- called the corona -- and light reflected off all the dust floating through space. The sunlight reflected off this dust, which slowly orbits the Sun, is about 100 times brighter than coronal light.

"We're not really dust people," said Howard, who is also the lead scientist for the cameras on STEREO and Parker Solar Probe that take pictures of the corona. "The dust close to the Sun just shows up in our observations, and generally, we have thrown it away." Solar scientists like Howard -- who study solar activity for purposes such as forecasting imminent space weather, including giant explosions of solar material that the Sun can sometimes send our way -- have spent years developing techniques to remove the effect of this dust. Only after removing light contamination from dust can they clearly see what the corona is doing.

The two scientists built their model as a tool for others to get rid of the pesky dust in STEREO -- and eventually Parker Solar Probe -- images, but the prediction of dust-free space lingered in the back of their minds. If they could devise a way of separating the two kinds of light and isolate the dust-shine, they could figure out how much dust was really there. Finding that all the light in an image came from the corona alone, for example, could indicate they'd found dust-free space at last.

Mercury's dust ring was a lucky find, a side discovery Stenborg and Howard made while they were working on their model. When they used their new technique on the STEREO images, they noticed a pattern of enhanced brightness along Mercury's orbit -- more dust, that is -- in the light they'd otherwise planned to discard.

"It wasn't an isolated thing," Howard said. "All around the Sun, regardless of the spacecraft's position, we could see the same five percent increase in dust brightness, or density. That said something was there, and it's something that extends all around the Sun."

Scientists never considered that a ring might exist along Mercury's orbit, which is maybe why it's gone undetected until now, Stenborg said. "People thought that Mercury, unlike Earth or Venus, is too small and too close to the Sun to capture a dust ring," he said. "They expected that the solar wind and magnetic forces from the Sun would blow any excess dust at Mercury's orbit away."

With an unexpected discovery and sensitive new tool under their belt, the researchers are still interested in the dust-free zone. As Parker Solar Probe continues its exploration of the corona, their model can help others reveal any other dust bunnies lurking near the Sun.

Asteroids Hiding in Venus' Orbit

This isn't the first time scientists have found a dust ring in the inner solar system. Twenty-five years ago, scientists discovered that Earth orbits the Sun within a giant ring of dust. Others uncovered a similar ring near Venus' orbit, first using archival data from the German-American Helios space probes in 2007, and then confirming it in 2013, with STEREO data.

Since then, scientists determined the dust ring in Earth's orbit comes largely from the asteroid belt, the vast, doughnut-shaped region between Mars and Jupiter where most of the solar system's asteroids live. These rocky asteroids constantly crash against each other, sloughing dust that drifts deeper into the Sun's gravity, unless Earth's gravity pulls the dust aside, into our planet's orbit.

At first, it seemed likely that Venus' dust ring formed like Earth's, from dust produced elsewhere in the solar system. But when Goddard astrophysicist Petr Pokorny modeled dust spiraling toward the Sun from the asteroid belt, his simulations produced a ring that matched observations of Earth's ring -- but not Venus'.

This discrepancy made him wonder if not the asteroid belt, where else does the dust in Venus' orbit come from? After a series of simulations, Pokorny and his research partner Marc Kuchner hypothesized it comes from a group of never-before-detected asteroids that orbit the Sun alongside Venus. They published their work in The Astrophysical Journal Letters on March 12, 2019.

"I think the most exciting thing about this result is it suggests a new population of asteroids that probably holds clues to how the solar system formed," Kuchner said. If Pokorny and Kuchner can observe them, this family of asteroids could shed light on Earth and Venus' early histories. Viewed with the right tools, the asteroids could also unlock clues to the chemical diversity of the solar system.

Because it's dispersed over a larger orbit, Venus' dust ring is much larger than the newly detected ring at Mercury's. About 16 million miles from top to bottom and 6 million miles wide, the ring is littered with dust whose largest grains are roughly the size of those in coarse sandpaper. It's about 10 percent denser with dust than surrounding space. Still, it's diffuse -- pack all the dust in the ring together, and all you'd get is an asteroid two miles across.

Using a dozen different modeling tools to simulate how dust moves around the solar system, Pokorny modeled all the dust sources he could think of, looking for a simulated Venus ring that matched the observations. The list of all the sources he tried sounds like a roll call of all the rocky objects in the solar system: Main Belt asteroids, Oort Cloud comets, Halley-type comets, Jupiter-family comets, recent collisions in the asteroid belt.

"But none of them worked," Kuchner said. "So, we started making up our own sources of dust."

Perhaps, the two scientists thought, the dust came from asteroids much closer to Venus than the asteroid belt. There could be a group of asteroids co-orbiting the Sun with Venus -- meaning they share Venus' orbit, but stay far away from the planet, often on the other side of the Sun. Pokorny and Kuchner reasoned a group of asteroids in Venus' orbit could have gone undetected until now because it's difficult to point earthbound telescopes in that direction, so close to the Sun, without light interference from the Sun.

Co-orbiting asteroids are an example of what's called a resonance, an orbital pattern that locks different orbits together, depending on how their gravitational influences meet. Pokorny and Kuchner modeled many potential resonances: asteroids that circle the Sun twice for every three of Venus' orbits, for example, or nine times for Venus' ten, and one for one. Of all the possibilities, one group alone produced a realistic simulation of the Venus dust ring: a pack of asteroids that occupies Venus's orbit, matching Venus' trips around the Sun one for one.

But the scientists couldn't just call it a day after finding a hypothetical solution that worked. "We thought we'd discovered this population of asteroids, but then had to prove it and show it works," Pokorny said. "We got excited, but then you realize, 'Oh, there's so much work to do.'"

They needed to show that the very existence of the asteroids makes sense in the solar system. It would be unlikely, they realized, that asteroids in these special, circular orbits near Venus arrived there from somewhere else like the asteroid belt. Their hypothesis would make more sense if the asteroids had been there since the very beginning of the solar system.

The scientists built another model, this time starting with a throng of 10,000 asteroids neighboring Venus. They let the simulation fast forward through 4.5 billion years of solar system history, incorporating all the gravitational effects from each of the planets. When the model reached present-day, about 800 of their test asteroids survived the test of time.

Pokorny considers this an optimistic survival rate. It indicates that asteroids could have formed near Venus' orbit in the chaos of the early solar system, and some could remain there today, feeding the dust ring nearby.

The next step is actually pinning down and observing the elusive asteroids. "If there's something there, we should be able to find it," Pokorny said. Their existence could be verified with space-based telescopes like Hubble, or perhaps interplanetary space-imagers similar to STEREO's. Then, the scientists will have more questions to answer: How many of them are there, and how big are they? Are they continuously shedding dust, or was there just one break-up event?

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Genes that evolve from scratch expand protein diversity

Rice plants

One of the most important questions in biology is how rapidly new proteins evolve in organisms. Proteins are the building blocks that carry out the basic functions of life. As the genes that produce them change, the proteins change as well, introducing new functionality or traits that can eventually lead to the evolution of new species.

A new study published in Nature Ecology and Evolution led by scientists from the University of Chicago challenges one of the classic assumptions about how new proteins evolve. The research shows that random, noncoding sections of DNA can quickly evolve to produce new proteins. These de novo, or "from scratch," genes provide a new, unexplored way that proteins evolve and contribute to biodiversity.

"Using a big genome comparison, we show that noncoding sequences can evolve into completely novel proteins. That's a huge discovery," said Manyuan Long, PhD, the Edna K. Papazian Distinguished Service Professor of Ecology and Evolution at UChicago and senior author of the new study.

A third way for genes to evolve

For decades, scientists believed that there were only two ways new genes evolved: duplication and divergence or recombination. During the normal process of replication and repair, a section of DNA gets copied and creates a duplicate version of the gene. Then, one of these copies may acquire mutations that change its functionality enough that it diverges and becomes a distinct new gene. With recombination, pieces of genetic material are reshuffled to create new combinations and new genes. However, these two methods only account for a relatively small number of proteins, given the total number of possible combinations of amino acids that comprise them.

Scientists have long wondered about a third mechanism, where de novo genes could evolve from scratch. All organisms have long stretches of genetic material that do not encode proteins, sometimes up to 97 percent of the total genome. Is it possible for these noncoding sections to acquire mutations that suddenly make them functional?

This has been difficult to study because it requires high-quality reference genomes from several closely related species that show both the ancestral, noncoding sequences and subsequent new genes that evolved from them. Without this clear, visible line of evolution, there's no way to prove it's truly a de novo gene. The supposed new genes reported previously could just be an "orphaned gene" that diverged or transferred from unrelated organisms at some point, then all traces of its predecessors disappeared.

To overcome these challenges, Long's team took advantage of 13 new genomes sequenced and annotated recently from 11 closely-related species of rice plants, including Oryza sativa, the most common food crop. He worked with groups headed by Prof. Rod Wing at the University of Arizona. Prof. Yidan Ouyang from Huazhong Agricultural University, China, also led a team that cultivated their own rice plants in Hainan, a tropical island off the southern coast of China, and harvested them for proteomics sampling.

After analyzing the genomes of these plants, they detected at least 175 de novo genes. Further mass spectrometry analysis of protein activity was conducted by another group led by Prof. Siqi Liu at BGI-Shenzhen, a genome sequencing center located in Shenzhen, Guangdong, China. They found evidence that 57 percent of these genes actually translated into new proteins, including more than 300 new peptides.

With this first, large dataset of authentic de novo genes, Long's team detected a pattern in their evolution. It began with the early evolution of expression, followed by subsequent mutation into protein coding potentials for almost all de novo genes.

"This makes sense given the widely observed expression of intergenic regions in various organisms," said Li Zhang, a postdoctoral researcher at UChicago and lead author of the article.

Long says that the Oryza plants are good genomes to search for de novo genes because they are relatively young -- you can still see evidence of evolution in their existing genomes.

"The 11 species diverged from each other only about three to four million years ago, so they are all young species," he said. "For that reason, when we sequence the genomes, all the sequences are highly similar. They haven't accumulated multiple generations of changes, so all the previous non-coding sections are still there."

Long and his team next want to study the new proteins to further understand their function and evolution and see if there is something unique about their structure. If de novo genes open up an unexplored path for evolution, they could reveal mechanisms for creating new and improved cellular functions. For instance, the researchers detected evidence of natural selection acting to fix insertions and deletions in the genome to generate new protein sequences, and the sequence's evolution toward improved functions.

Read more at Science Daily

Palaeolithic art featuring birds and humans discovered

Image of the findings with a tracing of the engraved figures on the piece.

It is not very common to find representations of scenes instead of individual figures in Palaeolithic art, but it is even harder for these figures to be birds instead of mammals such as goats, deer or horses. So far, historians have only found three scenes of Palaeolithic art featuring humans and birds in Europe.

Now, an article published in the journal L'Anthropologie tells how University of Barcelona researchers found -in the site of Hort de la Bequera (Margalef de Montsant, Priorat)-, an artistic piece from 12,500 years ago in which humans and birds try to interact in a pictorial scene with exceptional traits: figures seem to star a narration on hunting and motherhood. Regarding the Catalan context in particular, this is an important finding regarding the few pieces of Palaeolithic art in Catalonia and it places this territory within the stream of artistic production of the upper Palaeolithic in the Mediterranean.

The piece they found is a 30-centimeter long limestone which shows two human figures and two birds, which the researchers identified as cranes. Since they found the piece in 2011, they underwent all cleaning, restoration and 3D copying procedures to study it in detail. Those figures were engraved in the stone board with a flint tool so that they created an organized composition compared to the other pieces of the same period.

"This is one of the few found scenes so far which suggest the birth of a narrative art in Europe, and this theme is unique, since it combines an image of hunting and a motherhood one: a birth with its young one," says the first signer of the article, ICREA researcher and lecturer at the UB Inés Domingo. "In the represented scene the birds catch the attention, they are copied or chased by two human figures," continues Domingo. "We do not know the meaning of the scene for prehistoric peoples, but what it says is that not only they were regarded as preys but also as a symbol for European Palaeolithic societies," she continues.

"We do not doubt this is an exceptional milestone in European Palaeolithic rock art due its singularity, its excellent conservation and the chances to study it within a general context of excavation," say the authors of the article; members of the Prehistoric Studies and Research Seminar (SERP). Apart from Domingo, other signers are the UB lecturers of Prehistory Pilar García Argüelles, Jordi Nadal, directors of the excavation in Host de la Boquera, Professor Josep Maria Fullola, director of SERP, and José L. Lerma and the researcher Miriam Cabrelles, from Universitat Politècnica de València, who worked on the 3D reproduction of this piece.

Palaeolithic art in Montsant valley

The other sites in Europe researchers had found so far with human and bird figures are rock paintings in the site of Lascauz, a perforated baton in Abri Mege (Teyjat, Dordogne), and the Great Hunter plaque in the site of Gönnersdorf (Germany).

SERP researchers have been excavating in the valley of Montsant since 1979, an exceptional area regarding findings of this period of the late upper Palaeolithic. In particular, excavations have taken place in Host de la Boquera since 1998 and it provided a great amount of flint tools and structure such as rooms for a fireplace.

The director of the excavation, Pilar García Argüelles notes that "the findings of the engraved scene are exceptional, and proves the importance of the site and the area regarding Palaeolithic art in the peninsular north-east area; where we can find nearby the only Palaeolithic cave engraving in Catalonia, the deer in the cave of Taverna (Margalef de Montsant), and about 40 kilometres away there is Molí del Salt (Vimbodí), with an interesting series of stone blocks with engraved animals and a representation of huts."

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Teenage T. rex was already chomping on prey

Joseph Peterson, a vertebrate paleontologist at the University of Wisconsin Oshkosh, demonstrates how a T. rex takes a bite.

New research from the University of Wisconsin Oshkosh indicates that even as a teenager the Tyrannosaurus rex showed signs that it would grow up to be a ferocious predator.

In a study published last week in the peer-reviewed journal Peerj -- the Journal of Life and Environmental Sciences, UWO scientists reported evidence that a juvenile T. rex fed on a large plant-eating dinosaur, even though it lacked the bone-crushing abilities it would develop as an adult.

While studying fossils from an Edmontosaurus -- a plant-eating Hadrosaurid or duck-billed dinosaur, UWO vertebrate paleontologist Joseph Peterson noticed three large, v-shaped, bite marks on a tail bone and wondered, "Who made these?"

Peterson knew that T. rex -- a member of the meat-eating dinosaur suborder known as Theropoda -- was "a likely culprit."

"We suspected that T. rex was responsible for the bit marks, because in the upper Cretaceous rock formation, where the hadrosaur was discovered, there are only a few carnivorous dinosaurs and other reptiles in the fossil record. Crocodile fossils are found there, but such a crocodile would have left tooth marks that are round rather than the elliptical punctures we found on the vertebra," Peterson explained.

"There also were small Velociraptor-like dinosaurs, but their teeth are too small to have made the marks. Finally, an adult T. rex would have made punctures that would have been too large! That's when we started considering a juvenile tyrannosaur."

To test the hypothesis, Peterson and geology student Karsen Daus, of Suamico, coated the fossil with a silicon rubber to make a silicone peel of the puncture marks.

They found that the dimensions of the "teeth" better matched a late-stage juvenile T. rex (11 to 12 years) than an adult (approximately 30 years).

"Although this T. rex was young, it really packed a punch," Peterson said.

"This is significant to paleontology because it demonstrates how T. rex -- the most popular dinosaur of all time -- may have developed changes in diet and feeding abilities while growing," he said. "This is part of a larger, ongoing research initiative by many paleontologists to better understand how T. rex grew and functioned as a living creature over 65 million years ago."

Most theropod feeding traces and bite marks are attributed to adults; juvenile tooth marks rarely have been reported in the literature, he added.

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Massive twin star discovered snuggling close to its stellar sibling

2MASS observations (background image) revealed a highly reddened source back in 2003 indicating the massive young nature of PDS 27. PIONIER on VLTI provides 2,000 times higher angular resolution making it possible to resolve PDS 27 as a binary system for the first time in 2019.

Astronomers have discovered a binary star system with the closest high-mass young stellar objects ever measured, providing a valuable "laboratory" to test theories on high mass binary star formation.

An international team led by the University of Leeds has determined the distance between the massive young star PDS 27 and its orbiting stellar companion to be just 30 astronomical units away or 4.5 billion km. That is roughly the distance between our Sun and Neptune, making them the stellar companions with the closest proximity ever determined for young high mass stars in a binary system -- a star system with two stars in orbit around a centre of mass.

Study lead author, Dr Evgenia Koumpia, from the School of Physics and Astronomy at Leeds, said: "This is a very exciting discovery, observing and simulating massive binaries at the early stages of their formation is one of the main struggles of modern astronomy. With PDS 27 and its companion we have now found the closest, most massive young stellar objects in binaries resolved to date.

"There is a shortage of known young massive binary systems in charted space. High mass stars have comparatively short lifespans, burning out and exploding as supernovae in only a few million years, making them difficult to spot. This limits our ability to test the theories on how these stars form."

As part of their study the team has also identified a companion object for another young massive star referred to as PDS 37. The analysis revealed a distance between PDS 37 and its companion to be between 42 to 54 astronomical units -comparable to the distance between the Sun and Pluto. While further apart than PDS 27 and its companion, it is still a significant discovery given the need for confirmed massive young stellar binaries in astronomical research.

Dr Koumpia continued: "How these binary systems form is quite a controversial question with several theories having been put forward. Observational studies of binaries in their early stages are crucial to verifying the theories of their formation.

"PDS 27 and PDS 37 are rare and important laboratories that can help inform and test the theories on the formation of high mass binaries."

PDS 27 is at least 10 times more massive than our Sun, Dr Koumpia explained, and about 8,000 light years away. To determine the presence of stellar companions for PDS 27 and PDS 37, the team used the highest spatial resolution provided by the PIONIER instrument on the European Southern Observatory's Very Large Telescope Interferometer (VLTI). This instrument combines light beams from four telescopes, each of which is 8.2 metres across, and mimics a single telescope with a diameter of 130m. The resulting high spatial resolving power allowed the team to resolve such close binary systems despite their huge distance from us and their close proximity to each other.

Study co-author Professor Rene Oudmaijer, also from the School of Physics and Astronomy at Leeds, said: "The next big question -- which we have tended to avoid so far because of observational difficulties -- is why so many of these massive stars are in binary systems?"

"It has become increasingly clear to astronomers that massive stars are almost never born alone, with at least one sibling for company. But the reasons why that is the case are still rather murky.

"Massive stars exert significant influence on their cosmic environment. Their stellar winds, energy and the supernova explosions they generate in turn can impact the formation of other stars and galaxies. The evolution and fate of high-mass stars is quite complex but previous studies have shown that they can be influenced to a large degree by their binary properties.

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Kepler Space Telescope's first exoplanet candidate confirmed

Sound waves propagating through the stellar interior were used to characterize the star and the planet. Kepler-1658b, orbiting with a period of just 3.8 days, was the first exoplanet candidate discovered by Kepler nearly 10 years ago.

An international team of astronomers, led by University of Hawaii graduate student Ashley Chontos, announced the confirmation of the first exoplanet candidate identified by NASA's Kepler Mission. The result was presented at the fifth Kepler/K2 Science Conference held in Glendale, CA.

Launched almost exactly 10 years ago, the Kepler Space Telescope has discovered thousands of exoplanets using the transit method -- small dips in a star's brightness as planets cross in front of the star. Because other phenomena can mimic transits, Kepler data reveal planet candidates, but further analysis is required to confirm them as genuine planets.

Despite being the very first planet candidate discovered by NASA's Kepler Space Telescope, the object now known as Kepler-1658 b had a rocky road to confirmation. The initial estimate of the size of the planet's host star was incorrect, so the sizes of both the star and Kepler-1658 b were vastly underestimated. It was later set aside as a false positive when the numbers didn't quite make sense for the effects seen on its star for a body of that size. Fortuitously, Chontos' first year graduate research project, which focused on re-analyzing Kepler host stars, happened at just the right time.

"Our new analysis, which uses stellar sound waves observed in the Kepler data to characterize the host star, demonstrated that the star is in fact three times larger than previously thought. This in turn means that the planet is three times larger, revealing that Kepler-1658 b is actually a hot Jupiter-like planet," said Chontos. With this refined analysis, everything pointed to the object truly being a planet, but confirmation from new observations was still needed.

"We alerted Dave Latham (a senior astronomer at the Smithsonian Astrophysical Observatory, and co-author on the paper) and his team collected the necessary spectroscopic data to unambiguously show that Kepler-1658 b is a planet," said Dan Huber, co-author and astronomer at the University of Hawaii. "As one of the pioneers of exoplanet science and a key figure behind the Kepler mission, it was particularly fitting to have Dave be part of this confirmation."

Kepler-1658 is 50% more massive and three times larger than the Sun. The newly confirmed planet orbits at a distance of only twice the star's diameter, making it one of the closest-in planets around a more evolved star -- one that resembles a future version of our Sun. Standing on the planet, the star would appear 60 times larger in diameter than the Sun as seen from Earth.

Planets orbiting evolved stars similar to Kepler-1658 are rare, and the reason for this absence is poorly understood. The extreme nature of the Kepler-1658 system allows astronomers to place new constraints on the complex physical interactions that can cause planets to spiral into their host stars. The insights gained from Kepler-1658b suggest that this process happens slower than previously thought, and therefore may not be the primary reason for the lack of planets around more evolved stars.

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Scientists tackle major challenges to sending astronauts to search for life on Mars

Allyson Brady examines samples of basalt rock.

An international team of researchers, which includes scientists from McMaster's School of Geography & Earth Sciences, NASA, and others, is tackling one of the biggest problems of space travel to Mars: what happens when we get there?

A series of articles published today in a special edition of the journal Astrobiology, focuses on the scientific, logistical, operational and communications challenges of sending astronauts to deep space.

It is the culmination of years of work in NASA's BASALT research program, or the Biologic Analog Science Associated with Lava Terrains, which involves geologists, microbiologists, geneticists, engineers and astrobiologists from all over the world.

One of the biggest challenges the team is investigating is how best to conduct meaningful science in such harsh and dangerous conditions -- where time and resources are highly restricted -- and how to send valuable information back to Earth to enable input from an Earth-based science support team.

Researchers simulated mission conditions on Mars in several scenarios which included conducting field work in the unforgiving, Mars-like terrain of Craters of the Moon National Park Monument and Preserve in Idaho and the Hawaii Volcanoes National Park.

These regions are rich in basalt, a fine-grained rock similar to rock found on Mars. Scientists hope samples can provide important clues in the ongoing search for life on Mars.

Supported by funding from the Canadian Space Agency, Allyson Brady, a post-doctoral fellow in McMaster's School of Geography & Earth Sciences, who is working with her advisor Greg Slater on the project, is investigating organic biomarkers of microbial life associated with the rocks.

"When astronauts finally go to Mars, we need to identify the best place to potentially find evidence of life and to target the kind of basalt rock samples which may contain a lot of organic material, for example," explains Brady. "There will be many, many limitations on Mars so we need to consider the best way to conduct research and gather samples including getting timely feedback from science experts on Earth."

Brady and NASA scientists are also considering the challenges of sharing information when teams are millions of kilometres apart. For example, they tested different forms of communications -- video and photo transmissions, voice messaging, texting using specialized software -- between field researchers, who wore communications packs as an astronaut might, and mission control.

"There can be a significant delay, as long as 20 minutes, between an astronaut on Mars and the team on earth," explains Brady. "So we are working to optimize operations so astronauts don't have idle time and the flow of information continues," she says.

From Science Daily

Blood holds key to liver regeneration

The liver is the only organ in the body that can regenerate. But some patients who undergo a liver resection, a surgery that removes a diseased portion of the organ, end up needing a transplant because the renewal process doesn't work.

A new Michigan State University study, published in the journal Blood, shows that the blood-clotting protein fibrinogen may hold the key as to why this happens.

"We discovered that fibrinogen accumulates within the remaining liver quickly after surgery and tells platelets to act as first responders, triggering the earliest phase of regeneration," said James Luyendyk, a professor of pathobiology in the College of Veterinary Medicine. "But if fibrinogen or platelets are inhibited, then regeneration is delayed."

Platelets are blood cells that help form clots and stop bleeding. When they receive information from fibrinogen, they go into action and accumulate in the remaining part of the liver to help restore it, increasing the chances of a fully functional liver and successful recovery.

Using samples from patients undergoing liver resection and a comparable model in mice, Luyendyk and his team noticed that when fibrinogen was low, the number of platelets in the liver decreased.

"This shows that fibrinogen deposits are extremely important and directly impact regeneration in both mice and humans," Luyendyk said.

According to Dafna Groeneveld, Luyendyk's co-author and post-doctoral research associate in his lab, their finding demonstrates that fibrinogen levels could be a predictive marker for doctors, too.

"Measuring this protein in liver resection patients may help us determine in advance whether the organ will regenerate successfully or if it will become dysfunctional," she said.

This could lead to new treatments that would help doctors correct low levels of the protein by using fibrinogen concentrates that can be administered during surgery.

"This type of treatment hasn't been tried in liver resection patients yet," Luyendyk said. "But once we figure out exactly how fibrinogen works in the regeneration process and test potential therapies in mice, it could eventually provide the proof we need to bring our work into the clinic and improve patient outcomes."

From Science Daily

Music captivates listeners and synchronizes their brainwaves

Music has the ability to captivate us; when listeners engage with music, they follow its sounds closely, connecting to what they hear in an affective and invested way. But what is it about music that keeps the audience engaged? A study by researchers from The City College of New York and the University of Arkansas charts new ground in understanding the neural responses to music.

Despite the importance, it has been difficult to study engagement with music given the limits of self-report. This led Jens Madsen and Lucas Parra, from CCNY's Grove School of Engineering, to measure the synchronization of brainwaves in an audience. When a listener is engaged with music, their neural responses are in sync with that of other listeners, thus inter-subject correlation of brainwaves is a measure of engagement.

According to their findings, published in the latest issue of "Scientific Reports," a listener's engagement decreases with repetition of music, but only for familiar music pieces. However, unfamiliar musical styles can sustain an audience's interest, in particular for individuals with some musical training.

"Across repeated exposures to instrumental music, inter-subject correlation decreased for music written in a familiar style," Parra and his collaborators write in "Scientific Reports."

In addition, participants with formal musical training showed more inter-subject correlation, and sustained it across exposures to music in an unfamiliar style. This distinguishes music from other domains, where interest drops with repetition.

"What is so cool about this, is that by measuring people's brainwaves we can study how people feel about music and what makes it so special." says Madsen.

Elizabeth Hellmuth Margulis and Rhimmon Simchy-Gross, both from the University of Arkansas, were among the other researchers. The study involved 60 graduate and undergraduate students from City College of New York and University of Arkansas.

From Science Daily

Horseshoe crabs are really relatives of spiders, scorpions

University of Wisconsin-Madison postdoctoral researcher Jesús Ballesteros holds a small horseshoe crab. A study he led with Integrative Biology Professor Prashant Sharma used robust genetic analysis to demonstrate that horseshoe crabs are arachnids like spiders, scorpions and ticks.

Blue-blooded and armored with 10 spindly legs, horseshoe crabs have perhaps always seemed a bit out of place.

First thought to be closely related to crabs, lobsters and other crustaceans, in 1881 evolutionary biologist E. Ray Lankester placed them solidly in a group more similar to spiders and scorpions. Horseshoe crabs have since been thought to be ancestors of the arachnids, but molecular sequence data have always been sparse enough to cast doubt.

University of Wisconsin-Madison evolutionary biologists Jesús Ballesteros and Prashant Sharma hope, then, that their recent study published in the journal Systematic Biology helps firmly plant ancient horseshoe crabs within the arachnid family tree.

By analyzing troves of genetic data and considering a vast number of possible ways to examine it, the scientists now have a high degree of confidence that horseshoe crabs do indeed belong within the arachnids.

"By showing that horseshoe crabs are part of the arachnid radiation, instead of a lineage closely related to but independent of arachnids, all previous hypotheses on the evolution of arachnids need to be revised," says Ballesteros, a postdoctoral researcher in Sharma's lab. "It's a major shift in our understanding of arthropod evolution."

Arthropods are often considered the most successful animals on the planet since they occupy land, water and sky and include more than a million species. This grouping includes insects, crustaceans and arachnids.

Horseshoe crabs have been challenging to classify within the arthropods because analysis of the animals' genome has repeatedly shown them to be related to arachnids like spiders, scorpions, mites, ticks and lesser-known creatures such as vinegaroons. Yet, "scientists assumed it was an error, that there was a problem with the data," says Ballesteros.

Moreover, horseshoe crabs possess a mix of physical characteristics observed among a variety of arthropods. They are hard-shelled like crabs but are the only marine animals known to breathe with book gills, which resemble the book lungs spiders and scorpions use to survive on land.

Only four species of horseshoe crabs are alive today, but the group first appeared in the fossil record about 450 million years ago, together with mysterious, extinct lineages like sea scorpions. These living fossils have survived major mass extinction events and today their blood is used by the biomedical industry to test for bacterial contamination.

Age is just one of the problems inherent in tracing their evolution, say Ballesteros and Sharma, since searching back through time to find a common ancestor is not easy to accomplish. And evidence from the fossil record and genetics indicates evolution happened quickly among these groups of animals, convoluting their relationships to one another.

"One of the most challenging aspects of building the tree of life is differentiating old radiations, these ancient bursts of speciation," says Sharma, a professor of integrative biology. "It is difficult to resolve without large amounts of genetic data."

Even then, genetic comparisons become tricky when looking at the histories of genes that can either unite or separate species. Some genetic changes can be misleading, suggesting relationships where none exist or dismissing connections that do. This is owed to phenomena such as incomplete lineage sorting or lateral gene transfer, by which assortments of genes aren't cleanly made across the evolution of species.

Ballesteros tested the complicated relationships between the trickiest genes by comparing the complete genomes of three out of the four living horseshoe crab species against the genome sequences of 50 other arthropod species, including water fleas, centipedes and harvestmen.

Using a complex set of matrices, taking care not to introduce biases in his analysis, he painstakingly teased the data apart. Still, no matter which way Ballesteros conducted his analysis, he found horseshoe crabs nested within the arachnid family tree.

He says his approach serves as a cautionary tale to other evolutionary biologists who may be inclined to cherry-pick the data that seem most reliable, or to toss out data that don't seem to fit. Researchers could, for example, "force" their data to place horseshoe crabs among crustaceans, says Sharma, but it wouldn't be accurate. The research team tried this and found hundreds of genes supporting incorrect trees.

Ballesteros encourages others to subject their evolutionary data to this kind of rigorous methodology, because "evolution is complicated."

Why horseshoe crabs are water dwellers while other arachnids colonized land remains an open question. These animals belong to a group called Chelicerata, which also includes sea spiders. Sea spiders are marine arthropods like horseshoe crabs, but they are not arachnids.

"What the study concludes is that the conquest of the land by arachnids is more complex than a single tradition event," says Ballesteros.

It's possible the common ancestor of arachnids evolved in water and only groups like spiders and scorpions made it to land. Or, a common ancestor may have evolved on land and then horseshoe crabs recolonized the sea.

"The big question we are after is the history of terrestrialization," says Sharma.

For Ballesteros, who is now studying the evolution of blindness in spiders living deep within caves in Israel, his motivations get to the heart of human nature itself.

Read more at Science Daily