A sharper look at the M87 black hole

The iconic image of the supermassive black hole at the center of M87 -- sometimes referred to as the "fuzzy, orange donut" -- has gotten its first official makeover with the help of machine learning. The new image further exposes a central region that is larger and darker, surrounded by the bright accreting gas shaped like a "skinny donut." The team used the data obtained by the Event Horizon Telescope (EHT) collaboration in 2017 and achieved, for the first time, the full resolution of the array.

In 2017, the EHT collaboration used a network of seven pre-existing telescopes around the world to gather data on M87, creating an "Earth-sized telescope." However, since it is infeasible to cover the Earth's entire surface with telescopes, gaps arise in the data -- like missing pieces in a jigsaw puzzle.

"With our new machine learning technique, PRIMO, we were able to achieve the maximum resolution of the current array," says lead author Lia Medeiros of the Institute for Advanced Study. "Since we cannot study black holes up-close, the detail of an image plays a critical role in our ability to understand its behavior. The width of the ring in the image is now smaller by about a factor of two, which will be a powerful constraint for our theoretical models and tests of gravity."

PRIMO, which stands for principal-component interferometric modeling, was developed by EHT members Lia Medeiros (Institute for Advanced Study), Dimitrios Psaltis (Georgia Tech), Tod Lauer (NOIRLab), and Feryal Özel (Georgia Tech). Their publication, "The Image of the M87 Black Hole Reconstructed with PRIMO," is now available in The Astrophysical Journal Letters.

"PRIMO is a new approach to the difficult task of constructing images from EHT observations," said Lauer. "It provides a way to compensate for the missing information about the object being observed, which is required to generate the image that would have been seen using a single gigantic radio telescope the size of the Earth."

PRIMO relies on dictionary learning, a branch of machine learning which enables computers to generate rules based on large sets of training material. For example, if a computer is fed a series of different banana images -- with sufficient training -- it may be able to determine if an unknown image is or is not a banana. Beyond this simple case, the versatility of machine learning has been demonstrated in numerous ways: from creating Renaissance-style works of art to completing the unfinished work of Beethoven. So how might machines help scientists to render a black hole image? The research team has answered this very question.

With PRIMO, computers analyzed over 30,000 high-fidelity simulated images of black holes accreting gas. The ensemble of simulations covered a wide range of models for how the black hole accretes matter, looking for common patterns in the structure of the images. The various patterns of structure were sorted by how commonly they occurred in the simulations, and were then blended to provide a highly accurate representation of the EHT observations, simultaneously providing a high fidelity estimate of the missing structure of the images. A paper pertaining to the algorithm itself was published in The Astrophysical Journal on February 3, 2023.

"We are using physics to fill in regions of missing data in a way that has never been done before by using machine learning," added Medeiros. "This could have important implications for interferometry, which plays a role in fields from exo-planets to medicine."

The team confirmed that the newly rendered image is consistent with the EHT data and with theoretical expectations, including the bright ring of emission expected to be produced by hot gas falling into the black hole. Generating an image required assuming an appropriate form of the missing information, and PRIMO did this by building on the 2019 discovery that the M87 black hole in broad detail looked as predicted.

"Approximately four years after the first horizon-scale image of a black hole was unveiled by EHT in 2019, we have marked another milestone, producing an image that utilizes the full resolution of the array for the first time," stated Psaltis. "The new machine learning techniques that we have developed provide a golden opportunity for our collective work to understand black hole physics."

The new image should lead to more accurate determinations of the mass of the M87 black hole and the physical parameters that determine its present appearance. The data also provides an opportunity for researchers to place greater constraints on alternatives to the event horizon (based on the darker central brightness depression) and perform more robust tests of gravity (based on the narrower ring size). PRIMO can also be applied to additional EHT observations, including those of Sgr A*, the central black hole in our own Milky Way galaxy.

M87 is a massive, relatively nearby, galaxy in the Virgo cluster of galaxies. Over a century ago, a mysterious jet of hot plasma was observed to emanate from its center. Beginning in the 1950s, the then new technique of radio astronomy showed the galaxy to have a compact bright radio source at its center. During the 1960s, M87 had been suspected to have a massive black hole at its center powering this activity. Measurements made from ground-based telescopes starting in the 1970s, and later the Hubble Space Telescope starting in the 1990s, provided strong support that M87 indeed harbored a black hole weighing several billion times the mass of the Sun based on observations of the high velocities of stars and gas orbiting its center. The 2017 EHT observations of M87 were obtained over several days from several different radio telescopes linked together at the same time to obtain the highest possible resolution. The now iconic "orange donut" picture of the M87 black hole, released in 2019, reflected the first attempt to produce an image from these observations.

"The 2019 image was just the beginning," stated Medeiros. "If a picture is worth a thousand words, the data underlying that image have many more stories to tell. PRIMO will continue to be a critical tool in extracting such insights."

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Whether physical exertion feels 'easy' or 'hard' may be due to dopamine levels, study suggests

Dopamine, a brain chemical long associated with pleasure, motivation and reward-seeking, also appears to play an important role in why exercise and other physical efforts feel "easy" to some people and exhausting to others, according to results of a study of people with Parkinson's disease led by Johns Hopkins Medicine researchers. Parkinson's disease is marked by a loss of dopamine-producing cells in the brain over time.

The findings, published online April 1 in NPG Parkinson's Disease, could, the researchers say, eventually lead to more effective ways to help people establish and stick with exercise regimens, new treatments for fatigue associated with depression and many other conditions, and a better understanding of Parkinson's disease.

"Researchers have long been trying to understand why some people find physical effort easier than others," says study leader Vikram Chib, Ph.D., associate professor in the Department of Biomedical Engineering at the Johns Hopkins University School of Medicine and research scientist at the Kennedy Krieger Institute. "This study's results suggest that the amount of dopamine availability in the brain is a key factor."

Chib explains that after a bout of physical activity, people's perception and self-reports of the effort they expended varies, and also guides their decisions about undertaking future exertions. Previous studies have shown that people with increased dopamine are more willing to exert physical effort for rewards, but the current study focuses on dopamine's role in people's self-assessment of effort needed for a physical task, without the promise of a reward.

For the study, Chib and his colleagues from Johns Hopkins Medicine and the Kennedy Krieger Institute recruited 19 adults diagnosed with Parkinson's disease, a condition in which neurons in the brain that produce dopamine gradually die off, causing unintended and uncontrollable movements such as tremors, fatigue, stiffness and trouble with balance or coordination.

In Chib's lab, 10 male volunteers and nine female volunteers with an average age of 67 were asked to perform the same physical task -- squeezing a hand grip equipped with a sensor -- on two different days within four weeks of each other. On one of the days, the patients were asked to take their standard, daily synthetic dopamine medication as they normally would. On the other, they were asked not to take their medication for at least 12 hours prior to performing the squeeze test.

On both days, the patients were initially taught to squeeze a grip sensor at various levels of defined effort, and then were asked to squeeze and report how many units of effort they put forth.

When the participants had taken their regular synthetic dopamine medication, their self-assessments of units of effort expended were more accurate than when they hadn't taken the drug. They also had less variability in their efforts, showing accurate squeezes when the researchers cued them to squeeze at different levels of effort.

In contrast, when the patients hadn't taken the medication, they consistently over-reported their efforts -- meaning they perceived the task to be physically harder -- and had significantly more variability among grips after being cued.

In another experiment, the patients were given a choice between a sure option of squeezing with a relatively low amount of effort on the grip sensor or flipping a coin and taking a chance on having to perform either no effort or a very high level of effort. When these volunteers had taken their medication, they were more willing to take a chance on having to perform a higher amount of effort than when they didn't take their medication.

A third experiment offered participants the choice between getting a small amount of guaranteed money or, with the flip of a coin, getting either nothing or a higher amount of money. Results showed no difference in the subjects on days when they took their medication and when they did not. This result, researchers say, suggests that dopamine's influence on risk-taking preferences is specific to physical effort-based decision-making.

Together, Chib says, these findings suggest that dopamine level is a critical factor in helping people accurately assess how much effort a physical task requires, which can significantly affect how much effort they're willing to put forth for future tasks. For example, if someone perceives that a physical task will take an extraordinary amount of effort, they may be less motivated to do it.

Understanding more about the chemistry and biology of motivation could advance ways to motivate exercise and physical therapy regimens, Chib says. In addition, inefficient dopamine signaling could help explain the pervasive fatigue present in conditions such as depression and long COVID, and during cancer treatments. Currently, he and his colleagues are studying dopamine's role in clinical fatigue.

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Oldest bat skeletons ever found described from Wyoming fossils

Scientists have described a new species of bat based on the oldest bat skeletons ever recovered. The study on the extinct bat, which lived in Wyoming about 52 million years ago, supports the idea that bats diversified rapidly on multiple continents during this time. Led by researchers at the American Museum of Natural History and Naturalis Biodiversity Center in the Netherlands, the study is published today in the journal PLOS ONE.

There are more than 1,460 living species of bats found in nearly every part of the world, with the exception of the polar regions and a few remote islands. In the Green River Formation of Wyoming -- a remarkable fossil deposit from the early Eocene -- scientists have uncovered over 30 bat fossils in the last 60 years, but until now they were all thought represent the same two species.

"Eocene bats have been known from the Green River Formation since the 1960s. But interestingly, most specimens that have come out of that formation were identified as representing a single species, Icaronycteris index, up until about 20 years ago, when a second bat species belonging to another genus was discovered," said study co-author Nancy Simmons, curator-in-charge of the Museum's Department of Mammalogy, who helped describe that second species in 2008. "I always suspected that there must be even more species there."

In recent years, scientists from the Naturalis Biodiversity Center started looking closely at Icaronycteris index by collecting measurements and other data from museum specimens.

"Paleontologists have collected so many bats that have been identified as Icaronycteris index, and we wondered if there were actually multiple species among these specimens," said Tim Rietbergen, an evolutionary biologist at Naturalis. "Then we learned about a new skeleton that diverted our attention."

The exceptionally well-preserved skeleton was collected by a private collector in 2017 and purchased by the Museum. When researchers compared the fossil to Rietbergen's expansive dataset, it clearly stood out as a new species. A second fossil skeleton discovered in the same quarry in 1994 and in the collections of the Royal Ontario Museum was also identified as this new species. The researchers gave these fossils the species name Icaronycteris gunnelli in honor of Gregg Gunnell, a Duke University paleontologist who died in 2017 and made extensive contributions to the understanding of fossil bats and evolution.

Although there are fossil bat teeth from Asia that are slightly older, the two I. gunnelli fossils represent the oldest bat skeletons ever found.

"The Fossil Lake deposits of the Green River Formation are simply amazing because the conditions that created the paper-thin limestone layers also preserved nearly everything that settled to the lake's bottom," said Arvid Aase, park manager and curator at the Fossil Butte National Monument, in Wyoming. "One of these bat specimens was found lower in the section than all other bats, making this species older than any of the other bat species recovered from this deposit."

While the I. gunnelli skeletons are the oldest bat fossils from this site, they are not the most primitive, supporting the idea that Green River bats evolved separately from other Eocene bats around the world.

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M87 in 3D: New view of galaxy helps pin down mass of the black hole at its core

Seen from Earth, the giant elliptical galaxy M87 is just a two-dimensional blob, though one that appears perfectly symmetrical and thus a favored target of amateur astronomers.

Yet, a new, highly detailed analysis of the motion of stars around its central supermassive black hole — the first black hole to be imaged by the Event Horizon Telescope (EHT) in 2019 — reveals that it's not as perfect as it looks.

In fact, M87 is highly asymmetrical, like a russet potato. The galaxy's shortest axis is about three-fourths (72.2%) the length of its long axis, while the intermediate axis is about seven-eighths (84.5%) that of the long axis.

Knowing this, University of California, Berkeley, astronomers were able to determine the mass of the supermassive black hole at the galaxy's core to a high precision, estimating it at 5.37 billion times the mass of the sun. By comparison, our own Milky Way has at its center a massive black hole only 4 million times the mass of the sun.

They also were able to measure the rotation of the galaxy, which is a relatively sedate 25 kilometers per second. Interestingly, it is not rotating around any of the galaxy's major axes, but instead about an axis that is 40 degrees away from the long axis of its 2D image as observed by the Hubble Space Telescope.

The stereo reconstruction of the M87 galaxy and the more precise figure for the mass of the central black hole could help astrophysicists learn about a characteristic of the black hole they've had no way to determine before for any black hole: its spin.

"Now that we know the direction of the net rotation of stars in M87 and have an updated mass of the black hole, we can combine this information with the amazing data from the EHT team to constrain the spin," said Chung-Pei Ma, a UC Berkeley professor of astronomy and of physics who led the research. "This may point toward a certain direction and range of spin for the black hole, which would be remarkable. We are working on this.”

Further analyses to determine the true shape of giant elliptical galaxies — the galaxies with the largest black holes at their cores — will help astronomers understand better how large galaxies and large black holes form and could help astronomers better interpret gravitational wave signals. Ma leads a long-term study of supermassive black holes that is dubbed MASSIVE.

The results were published online March 15 in The Astrophysical Journal Letters (ApJ Letters).

Determining a galaxy's 3D shape

While spiral galaxies tend to be small, rotate quickly and have a well-recognized pancake shape, giant elliptical galaxies rotate slowly and have a blobby appearance, their 3D shape difficult to discern. Like M87, the largest galaxy in the massive Virgo Cluster of galaxies, giant elliptical galaxies have grown from the merger of many other galaxies. That's likely the reason M87's central black hole is so large — it assimilated the central black holes of all the galaxies it swallowed. In all, the galaxy contains about 100 billion stars, 10 times larger than the Milky Way.

Ma, UC Berkeley graduate student and lead author Emily Liepold, and Jonelle Walsh at Texas A&M University in College Station were able to determine the 3D shape of M87 thanks to a relatively new precision instrument mounted on the Keck II Telescope, one of the twin 10-meter Keck telescopes atop Mauna Kea, a volcano in Hawai'i. Called the Keck Cosmic Web Imager (KCWI), the integral field spectrometer allowed Ma and her team to measure the spectra of stars in the center of the galaxy.

They pointed the telescope at 62 adjacent locations in the galaxy, completely covering a region about 70,000 light-years across, and recorded the spectra of stars within that region. The observations span the central region — about 3,000 light-years across — where gravity is largely dominated by the supermassive black hole, as well as the outer part dominated by dark matter. Though the telescope cannot resolve individual stars — M87 lies about 53 million light- years from Earth — the spectra can reveal the range of velocities within each pixel of each image, enough information to calculate the gravitational mass they're orbiting.

"It's sort of like looking at a swarm of 100 billion bees that are going around in their own happy orbits," said Ma, the Judy Chandler Webb Professor in the Physical Sciences. "Though we are looking at them from a distance and can’t discern individual bees, we are getting very detailed information about their collective velocities. It's really the superb sensitivity of this spectrograph that allowed us to map out M87 so comprehensively."

This is the first time KCWI has been used to reconstruct the geometry of a distant galaxy, and M87 is one of only a handful of giant elliptical galaxies whose 3D structure has been determined. Ma’s team had previously determined the 3D structure of two other giant elliptical galaxies, NGC 1453 and NGC 2693, both harboring smaller black holes than M87.

The researchers took the data obtained during four nights of Keck observations between 2020 and 2022, along with earlier photometric data for M87 from NASA's Hubble Space Telescope, and compared them to computer model predictions of how stars move around the center of a triaxial galaxy. The best fit to the data — axial ratios of 1 to 0.84 to 0.72 — then allowed them to calculate the black hole mass.

"The Keck data are so good that we can measure the intrinsic shape of M87 along with the black hole at the same time," Ma said. "We made the first measurement of the actual 3D shape of the galaxy. And since we allowed the swarm of bees to have a more general shape than just a sphere or disk, we have a more robust dynamical measurement of the mass of the central black hole that is governing the bees’ orbiting velocities."

The authors dedicated their manuscript to the late astronomer Wallace "Wal" Sargent, who first suggested that a supermassive black hole lurked at the center of M87 and calculated its mass to be about 5 billion solar masses.

"His number is a twiddle with our error bars, which is very interesting to see after decades of work," said Ma, who credits Sargent with being a mentor when she was a postdoctoral fellow at the California Institute of Technology.

The previous estimate of the mass of the supermassive black hole in M87, published in 2011, was based on a similar analysis of the dynamical movement of stars around the black hole, though that study assumed the galaxy was axisymmetric. The number, 6.14 billion solar masses, is within error bars of the new, more precise estimate. When imaging the black hole four years ago, the EHT scientists estimated the black hole mass to be 6.5 billion solar masses, 21% higher than the new number.

Interestingly, the dark matter within the volume of the galaxy they analyzed is much higher than that of the black hole — about 388 billion solar masses, or 67% of the entire mass of M87. Though the identity of dark matter is still a mystery, it makes up about 85% of the mass of the universe.

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James Webb Space Telescope images challenge theories of how universe evolved

The James Webb Space Telescope (JWST) appears to be finding multiple galaxies that grew too massive too soon after the Big Bang, if the standard model of cosmology is to be believed.

In a study published in Nature Astronomy, Mike Boylan-Kolchin, an associate professor of astronomy at The University of Texas at Austin, finds that six of the earliest and most massive galaxy candidates observed by JWST so far stand to contradict the prevailing thinking in cosmology. That's because other researchers estimate that each galaxy is seen from between 500 and 700 million years after the Big Bang, yet measures more than 10 billion times as massive as our sun. One of the galaxies even appears to be more massive than the Milky Way, despite that our own galaxy had billions of more years to form and grow.

"If the masses are right, then we are in uncharted territory," Boylan-Kolchin said. "We'll require something very new about galaxy formation or a modification to cosmology. One of the most extreme possibilities is that the universe was expanding faster shortly after the Big Bang than we predict, which might require new forces and particles."

For galaxies to form so fast at such a size, they also would need to be converting nearly 100% of their available gas into stars.

"We typically see a maximum of 10% of gas converted into stars," Boylan-Kolchin said. "So while 100% conversion of gas into stars is technically right at the edge of what is theoretically possible, it's really the case that this would require something to be very different from what we expect."

For all of the breathless excitement it evokes, JWST has presented astronomers with an unsettling dilemma. If the masses and time since the Big Bang are confirmed for these galaxies, fundamental changes to the reigning model of cosmology -- what's called the dark energy + cold dark matter (ΛCDM) paradigm, which has guided cosmology since the late 1990s -- could be needed. If there are other, faster ways to form galaxies than ΛCDM allows, or if more matter actually was available for forming stars and galaxies in the early universe than was previously understood, astronomers would need to shift their prevailing thinking.

The six galaxies' times and masses are initial estimates and will need follow-up confirmation with spectroscopy -- a method that splits the light into a spectrum and analyzes the brightness of different colors. Such analysis might suggest that central supermassive black holes, which could heat up the surrounding gas, may be making the galaxies brighter so that they look more massive than they really are. Or perhaps the galaxies are actually seen at a time much later than originally estimated due to dust that causes the color of the light from the galaxy to shift redder, giving the illusion of being more lightyears away and, thus, further back in time.

The galaxy data came from the Cosmic Evolution Early Release Science Survey (CEERS), a multi-institution JWST initiative led by UT Austin astronomer Steven Finkelstein.

Another ongoing collaborative JWST project, COSMOS-Web, co-led by UT Austin's Caitlin Casey, may be involved with spectroscopy and shedding more light on the findings to help resolve the dilemma. COSMOS-Web is covering an area roughly 50 times larger than CEERS and is expected to discover thousands of galaxies.

"It will be ideal for discovering the rarest, most massive galaxies at early times, which will tell us how the biggest galaxies and black holes in the early universe arose so quickly," Boylan-Kolchin said.

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New look at climate data shows substantially wetter rain and snow days ahead

A key source of information underpinning the upcoming National Climate Assessment suggests that heavy precipitation days historically experienced once in a century by Americans could in the future be experienced on several occasions in a lifetime.

Scientists at Scripps Institution of Oceanography at UC San Diego and the Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab) report that extremely intense days of rain or snow will be more frequent by the end of this century than previously thought -- as often as once every 30 or 40 years in the Pacific Northwest and southeastern United States.

The conclusions come from analyzing a 30-terabyte data set that models temperature and precipitation at scales roughly the size of urban ZIP codes: six kilometers (3.9 miles). Researchers developed the data set, called Localized Constructed Analogs Version 2 (LOCA2), to provide climate information that is useful for local planners. In contrast, most of the existing advanced climate models look at regions that range from 50 to 250 kilometers (30 to 400 miles).

"With this data set, we're able to look at the impacts of actual weather pattern changes across the United States at an extremely granular level," said Dan Feldman, staff scientist at Berkeley Lab and the project's principal investigator. "We see that there is a lot more extreme weather that is likely to happen in the future -- and by looking at actual weather patterns, we show that changes in extreme precipitation will actually be more extreme than previously estimated. Land use managers and planners should expect more extremes, but location matters."

The LOCA2 data set updates a similar analysis conducted in 2016 in advance of the Fourth National Climate Assessment (NCA), which was released in 2018 by the U.S. Global Change Research Program. The NCA is intended to assist the U.S. government with planning for, mitigating, and adapting to changes in climate that will affect the country. The Fifth NCA is expected to be issued later this year.

LOCA2 projections cover the lower 48 states of the United States, southern Canada, and northern Mexico. The data set draws on more than 70 years of weather data and incorporates 27 updated climate models from the Coupled Model Intercomparison Project (CMIP6), the latest iteration of an international effort to simulate climate that includes the "coupling" of natural systems such as the ocean and atmosphere to understand how they will act in concert as climate changes.

"We've spent a lot of effort improving the representation of extreme wet days, which is important for understanding both the likelihood of flooding and the availability of water for agricultural, commercial, and residential use," said David Pierce, a scientist at Scripps Oceanography and the developer of LOCA and LOCA2.

The LOCA2 climate projections are available through the end of the century down to the daily level, and for three different greenhouse gas emissions scenarios known as SSPs, or Shared Socioeconomic Pathways. The three scenarios are a medium level of emissions that is slightly less than current levels (SSP 245), medium-high (SSP 370), and high, where emissions greatly increase (SSP 585). The data set is freely available for planners and decision makers to use.

The projection reinforces what climate scientists have long predicted: Future weather events will become more extreme in a warming world. LOCA2 finds that the heaviest days of rain and snowfall across much of North America will likely release 20 to 30 percent more moisture than they do now. Much of the increased precipitation will occur in winter, potentially exacerbating flooding in regions such as the upper Midwest and the west coast.

"The big picture is clear: it's getting warmer and wetter," Feldman said. "This research translates that bigger picture into more practical data for infrastructure and operations planning. With this more detailed look at local impacts, we can help local officials make better-informed decisions, such as how long to make an airport runway, how much resilience to include for constructing buildings or bridges, or where to put crops or culverts."

The improved set of LOCA2 data was created by better identifying and preserving extreme weather events in the past, training models to more accurately reflect extremes in simulations of the future.

"We undertook a Herculean effort of personnel and computer time not just to produce a bunch of numbers, but to produce local projections that are relevant and useful," Feldman said. "We do so by recognizing how heat waves and storms have occurred and will occur at the local level, and projecting those forward."

Seasonal and regional predictions

While the data varies at the local level, researchers found substantial trends across the area covered by LOCA2 at the end of the century.

Across most seasons, a major part of North America will see roughly the same or fewer number of days with precipitation, roughly the same or fewer number of days with light and medium amounts of precipitation, and a large increase in the number of days with the most extreme precipitation (the top 1 percent and 0.1 percent of storms).

"People will be more affected by the really rare and most extreme events, because those are showing the biggest increase," said Pierce, who is the lead author of the paper on extreme precipitation published in the Journal of Hydrometeorology. "The wettest day you would expect to see in five years, or 50 years, or 500 years -- those extreme events are going to be substantially wetter, and that's a really big issue, because it has implications for flooding and run-off."

Southern Canada and most of the United States will see increases in extreme precipitation days that occur primarily in winter. The wettest days of precipitation will increase by 20-30 percent, depending on the emissions scenario and how extreme the storm is.

Arizona, New Mexico, and northern Mexico can expect increases in extreme precipitation days that occur primarily in autumn. The wettest days of precipitation increase by 10-30 percent, depending on which emissions scenarios come to be and how extreme the storms are. While the region becomes drier overall, the number of days with extreme precipitation events still goes up, meaning the precipitation that does come will often do so in larger storms.

"It's quite interesting that you see the same kind of pattern of fewer low- and medium- precipitation days and more extreme precipitation days across pretty much the entire country," Pierce said. Knowing the changing character of precipitation and the frequency of extreme events is useful in two ways, Pierce added. "One is for building new infrastructure in the future, and one is for understanding impacts upon existing facilities already there."

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Apes may have evolved upright stature for leaves, not fruit, in open woodland habitats

Anthropologists have long thought that our ape ancestors evolved an upright torso in order to pick fruit in forests, but new research from the University of Michigan suggests a life in open woodlands and a diet that included leaves drove apes' upright stature.

The finding sheds light on ape origins and pushes back the origin of grassy woodlands from between 7 million and 10 million years ago to 21 million years ago, during the Early Miocene.

Fruit grows on the spindly peripheries of trees. To reach it, large apes need to distribute their weight on branches stemming from the trunk, then reach out with their hands toward their prize. This is much easier if an ape is upright because it can more easily grab onto different branches with its hands and feet. If its back is horizontal, then its hands and feet are generally underneath the body, making it much harder to move outward to the smaller branches of a tree -- especially if the ape is large bodied.

This is how modern day apes reach fruit, and, it's been theorized, that's why apes evolved to be upright, according to U-M researchers Laura MacLatchy and John Kingston.

But new research centered around a 21-million-year-old fossil ape called Morotopithecus and led by MacLatchy suggests this might not be the case. Instead, researchers think early apes ate leaves and lived in a seasonal woodland with a broken canopy and open, grassy areas. The researchers suggest this landscape, instead of fruit in closed canopy forests, drove apes' upright stature.

Their results are published in Science and are bolstered by a companion paper examining these paleo grassy woodland habitats, published in the same issue of the journal.

"The expectation was: We have this ape with an upright back. It must be living in forests and it must be eating fruit. But as more and more bits of information became available, the first surprising thing we found was that the ape was eating leaves. The second surprise was that it was living in woodlands," said MacLatchy, a paleoanthropologist and professor in the U-M Department of Anthropology.

The two papers grew out of a U.S. National Science Foundation-funded collaboration of international paleontologists, collectively known as the Research on Eastern African Catarrhine and Hominoid Evolution project or REACHE, each of whom focus on different aspects of early ape paleoenvironments. The study led by MacLatchy focuses on a 21-million-year-old site called the Moroto site in eastern Uganda.

There, the group, which included U-M researchers William Sanders and Miranda Cosman, examined fossils found in a single stratigraphic layer, including fossils of the oldest, clearly documented ape, Morotopithecus. Also within this layer were fossils of other mammals, ancient soils called paleosols, and tiny silica particles from plants called phytoliths. The researchers used these lines of evidence to recreate the ancient environment of Morotopithecus.

MacLatchy and Kingston discovered that the plants living in this landscape were what's called "water stressed," meaning they lived through seasonal periods of rain and of aridity. This also means that at least part of the year, apes had to rely on something other than fruit to survive. Together, these findings indicate that Morotopithecus lived in an open woodland punctuated by broken canopy forests composed of trees and shrubs.

"These open environments have been invoked to explain human origins, and it was thought that you started to get these more open, seasonal environments between 10 and 7 million years ago," MacLatchy said. "Such an environmental shift is thought to have been selected for terrestrial bipedalism -- our ancestors started striding around on the ground because the trees were further apart.

"Now that we've shown that such environments were present at least 10 million years before bipedalism evolved, we need to really rethink human origins, too."

The first clue that these ancient apes were eating leaves was in the apes' molars. The molars were very "cresty": they were craggy, with peaks and valleys. Molars like this are used for tearing fibrous leaves apart, while molars used for eating fruit are typically more rounded, MacLatchy said.

The researchers also examined the apes' dental enamel, as well as the dental enamel of other mammals found in the same stratigraphic layer. They found that isotopic ratios -- the abundance of two isotopes of the same element -- in their dental enamel showed that the apes and other mammals had been eating water stressed C3 plants that are more common in open woodland or grassy woodland environments today. C3 plants are primarily woody shrubs and trees while C4 plants are arid-adapted grasses.

"Putting together the locomotion, the diet and the environment, we basically discovered a new model for ape origins," MacLatchy said. "In anthropology, we care a lot about ape evolution because humans are closely related to apes and features like lower back stability represent an arboreal adaptation that may have ultimately given rise to bipedal humans."

Early Miocene C4 grasses and open woodlands

Previously, researchers believed equatorial Africa during the Early Miocene was thickly carpeted with forest, and that open seasonal woodlands and grasslands evolved only between 7 million and 10 million years ago.

But the second paper uses a set of environmental proxies to reconstruct the vegetation structure from nine fossil ape sites across Africa, including the Moroto site, during the Early Miocene. These proxies revealed that C4 grasses were "everywhere" during that time period, said Kingston, a biological anthropologist and associate professor in the U-M Department of Anthropology.

"This paper looks at all these sites, pulls all this data together, and says, 'Look, no matter how you evaluate the data, there's no way you can escape the fact that all these proxies are converging on the same place -- namely, that these environments are open, and they're open with C4 grasses," he said.

"For the first time, we're showing that these grasses are widespread, and it's this general context of open seasonal woodland ecosystems that were integral in shaping the evolution of different mammalian lineages, including and especially in our case, how different ape lineages evolved."

The nine sites are scattered across eastern equatorial Africa, enough to develop a "regional picture" of what the sites' landscapes looked like in the Early Miocene, Kingston said. During this time, the East African Rift was forming. Earth was pulling apart. As a result, the entire region was uplifted, causing huge variation in topography, and therefore, regional climate and vegetation.

"There's mountains and volcanoes, there's cliffs and escarpments and valleys," Kingston said. "The landscape is just physically highly variable, and that, no doubt, is related to the vegetation heterogeneity."

To reconstruct the paleoenvironment at each location, the researchers used carbon isotope analyses of ancient soil organic matter, plant wax biomarkers and phytoliths found at each site. The carbon isotope analyses revealed that a wide range of plants lived in the grasslands, ranging from those that comprise closed canopy to wooded grasslands.

The wax biomarkers -- left over from the waxy material that protects leaves -- also indicate a large variety of shrubs and trees as well as grasses. Phytoliths -- microscopic biosilica bodies that give plants their structure as well as a defense against being eaten -- can tell the researchers the proportion of C4 grasses at a given site and provide further evidence for abundant C4 grasses.

After using these proxies to rebuild the paleoenvironments at these nine sites, the researchers found that C4 grasses were abundant across eastern equatorial Africa, and were a key part of the landscape's heterogeneous habitats. Their data also pushes back the oldest evidence of C4 grass-dominated habitats in Africa and globally by more than 10 million years.

"The findings have transformed what we thought we knew about early apes, and the origin for where, when and why they navigate through the trees and on the ground in multiple different ways," said Robin Bernstein, program director for biological anthropology at the National Science Foundation.

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Humans need Earth-like ecosystem for deep-space living

Can humans endure long-term living in deep space? The answer is a lukewarm maybe, according to a new theory describing the complexity of maintaining gravity and oxygen, obtaining water, developing agriculture and handling waste far from Earth.

Dubbed the Pancosmorio theory -- a word coined to mean "all world limit" -- it was described in a paper published in Frontiers in Astronomy and Space Sciences.

"For humans to sustain themselves and all of their technology, infrastructure and society in space, they need a self-restoring, Earth-like, natural ecosystem to back them up," said co-author Morgan Irons, a doctoral student conducting research with Johannes Lehmann, professor in the School of Integrative Plant Science at Cornell University. Her work focuses on soil organic carbon persistence under Earth's gravity and varying gravity conditions. "Without these kinds of systems, the mission fails."

The first key is gravity, which Earth life needs to function properly, said co-author Lee Irons, Morgan Irons' father and executive director of the Norfolk Institute, a group that aims to solve problems of human resilience on Earth and in space.

"Gravity induces a gradient in the fluid pressure within the body of the living thing to which the autonomic functions of the life form are attuned," he said. "An example of gravity imbalance would be the negative affect on the eyesight of humans in Earth orbit, where they don't experience the weight necessary to induce the pressure gradient."

Morgan Irons said that it would be unwise to spend billions of dollars to set up a space settlement only to see it fail, because even with all other systems in place, you need gravity.

Humans and all Earth life have evolved within the context of 1G of gravity. "Our bodies, our natural ecosystems, all the energy movement and the way we utilize energy is all fundamentally based upon 1G of gravity being present," she said. "There is just no other place in space where there is 1G of gravity; that just doesn't exist anywhere else in our solar system. That's one of the first problems we must solve."

Oxygen is another key factor. Earth's ecosystem generates oxygen for humans and other life forms. If a technologically advanced primary and a back-up system failed to provide oxygen for the moon base, for example, it would mean instant doom for the astronauts. "A reserve exists everywhere in Earth's nature," Lee Irons said. "Think of the hundreds of thousands of species of plants that generate oxygen. That's the kind of system reserve we need to replicate to be truly sustainable."

Such an ecological system of an outpost would need an enormous amount energy from the sun. The more distant planets and moons from the sun in our own solar system get decreased amounts of energy.

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Lightning strike creates phosphorus material

After lightning struck a tree in a New Port Richey neighborhood, a University of South Florida professor discovered the strike led to the formation of a new phosphorus material. It was found in a rock -- the first time in solid form on Earth -- and could represent a member of a new mineral group.

"We have never seen this material occur naturally on Earth -- minerals similar to it can be found in meteorites and space, but we've never seen this exact material anywhere," said geoscientist Matthew Pasek.

In a recent study published in Communications Earth & Environment, Pasek examines how high-energy events, such as lightning, can cause unique chemical reactions, and in this instance, result in a new material -- one that is transitional between space minerals and minerals found on Earth.

"When lightning strikes a tree, the ground typically explodes out and the surrounding grass dies, forming a scar and sending electric discharge through nearby rock, soil and sand, forming fulgurites, also known as 'fossilized lightning'," Pasek said.

When the New Port Richey homeowners discovered the 'lightning scar', they found a fulgurite and decided to sell it, assuming it had value. Pasek purchased it, and later began a collaboration with Luca Bindi, a professor of mineralogy and crystallography at the University of Florence in Italy.

Together, the team set out to investigate unusual minerals that bear the element phosphorus, especially those formed by lightning, to better understand high-energy phenomena.

"It's important to understand how much energy lightning has because then we know how much damage a lightning strike can cause on average and how dangerous it is," Pasek said. "Florida is the lightning capital of the world and lightning safety is important -- if lightning is strong enough to melt rock, it can certainly melt people too."

In wet environments, such as in Florida, Pasek says iron will often accumulate and encrust tree roots. In this case, not only did the lightning strike combust the iron on the tree roots, but it combusted the naturally occurring carbon in the tree as well. The two elements led to a chemical reaction that created a fulgurite that looked like a metal 'glob.'

Inside the fulgurite, a colorful, crystal-like matter revealed a material never before discovered.

Co-principal investigator Tian Feng, a graduate of USF's geology program, attempted to remake the material in a lab. The experiment was unsuccessful and indicates the material likely forms quickly under precise conditions, and if heated too long, will turn into the mineral found in meteorites.

"Previous researchers indicate that lightning reduction of phosphate to have been a widespread phenomenon on the early Earth," Feng said. "However, there is an environmental phosphite reservoir issue in Earth that these solid phosphite materials are hard to restore."

Feng says this research may reveal other forms of reduced minerals are plausible and many could have been important in the development of life on Earth.

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Increased droughts are disrupting carbon-capturing soil microbes, concerning ecologists

Soil stores more carbon than plants and the atmosphere combined, and soil microbes are largely responsible for putting it there. However, the increasing frequency and severity of drought, such as those that have been impacting California, could disrupt this delicate ecosystem. In a perspective publishing in the journal Trends in Microbiology on April 12, microbial ecologist Steven Allison warns that soil health and future greenhouse gas levels could be impacted if soil microbes adapt to drought faster than plants do. He argues that we need to better understand how microbes respond to drought so that we can manage the situation in both agricultural and natural settings.

"Soil microbes are beneficial, and we couldn't live without their cycling of carbon and nutrients, but climate change and drought can tweak that balance, and we have to be aware of how it's changing," says Allison of the University of California, Irvine.

Some soil microbes take carbon from decomposing plants and store it in the soil, while others release plant carbon back into the atmosphere. The carbon that ends up in the soil is beneficial in multiple ways. "The carbon in the soil has these reverberating effects out to the rest of the world in terms of the infrastructure in our natural and managed ecosystems," says Allison. "Carbon-rich soils hold more nutrients, so plants growing in those soils tend to be more productive, and the carbon changes the physical properties of the soil, which prevents erosion."

"In California now, we have this system where the droughts are more intense, and then the rainfall is more intense," he says. "So, if you're losing your soil carbon, when it rains really hard it could carry away your soil and cause erosion, landslides, mudslides, sediments, and all kinds of problems that we're actually seeing right now."

The carbon that is released back into the atmosphere is another story. "From a climate mitigation standpoint, what we want is for more carbon to be in plants and soils and less carbon to be in the atmosphere, so the more carbon we can absorb into plants through photosynthesis and the more we can transfer and keep in the soil, the better off we're going to be in terms of climate change," says Allison. "That's why it's really important to know how the balance of incoming versus outflowing carbon changes with drought, or warming, or any other climate factor."

Plants and microbes will both be impacted by the increasing frequency of drought, but Allison suspects that microbes will be able to bounce back faster. "Microbes are really adaptable -- they can change their physiology, they can change their abundances so that more drought-adapted microbes take over, and they can potentially evolve -- so we expect that they are going to resist or bounce back from drought," says Allison. "All those different processes can happen pretty quickly with microbes, and much more quickly than with plants."

If more carbon-releasing microbes survive than carbon-sequestering microbes, we could end up with carbon-depleted soils, which would have serious negative implications for plant productivity and future greenhouse gas levels.

We may be able to nudge the balance in the right direction, Allison says, but more research is needed first. "There's still a lot to be done. Right now, we have data that suggests that when we have drought, something changes that results in carbon loss, but we don't understand exactly how or why that's happening, whether drought's changing the abundance of beneficial plant associated microbes versus the carbon releasing microbes, or if it's causing the evolution of one of the microbe groups, or if it's more determined by changes to their immediate physiology," says Allison.

Some microbes could actually help plants cope with drought. If we knew which microbes were most beneficial to plants, and most likely to retain carbon in soil, we could try to tip the balance in their favor.

"There's a lot of potential for us to manage or engineer soil microbes," says Allison. "In agricultural systems, we can look into manipulating the soil or adding beneficial microbes back in. In more natural systems, management would probably be on the plant side: soil microbes are often closely intertwined with plants, so managing the plants can also benefit the microbial part of the ecosystem."

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