The Closest Exoplanet to Earth May Have Neighbors

An artist's impression of the newly detected dusty belts around the sun's nearest neighbor, the red dwarf Proxima Centauri, and its potentially rocky world.

The nearest alien planet to Earth may not be an only child.

Astronomers have spotted a dusty ring around the nearby star Proxima Centauri, hinting at the existence of other planets in addition to the famous Proxima b, a new study reports.

"This result suggests that Proxima Centauri may have a multiple-planet system with a rich history of interactions that resulted in the formation of a dust belt," study lead author Guillem Anglada, an astronomer at the Instituto de Astrofisica de Andalucia in Spain, said in a statement. "Further study may also provide information that might point to the locations of as-yet unidentified additional planets."

Proxima Centauri is a red dwarf that lies about 4.2 light-years from Earth, in the southern constellation of Centaurus (The Centaur). In 2016, researchers spotted Proxima b, an apparently Earth-size world orbiting the star in what seems to be the habitable zone, the region where liquid water could exist on the surface. The star itself is about the same age as the sun. (Coincidentally, the team that discovered Proxima b was led by Guillem Anglada-Escudé of Queen Mary University of London, a part of Anglada's team but no relation to the author of the new research.)

Anglada and his colleagues studied Proxima Centauri using the Atacama Large millimeter/submillimeter Array (ALMA), a network of telescopes in Chile. The researchers discovered a belt of dusty material containing about 1 percent the mass of Earth. The belt — which lies a few hundred million kilometers from the star, far beyond Proxima b's orbit — has a temperature of about minus 328 degrees Fahrenheit (minus 230 degrees Celsius), roughly the same temperature of the solar system's Kuiper Belt, researchers said.

This image of the sky around the bright binary star Alpha Centauri AB also shows the much fainter red dwarf star, Proxima Centauri, the closest star to our own solar system. The photo was created from pictures forming part of the Digitized Sky Survey 2. The blue halo around Alpha Centauri AB is an artifact of the photographic process; the binary is really pale yellow in color, like the sun.

The dusty material might range in size from grains of only a few millimeters to asteroid-like bodies several kilometers across, study team members said. Dust belts like this are thought to be the remains of material that didn’t manage to clump together to form planets, they added.

ALMA also spotted signs of a possible second dust ring, about 10 times farther from the star than the other one, though this feature awaits confirmation. If the outer ring does indeed exist, its material would be very cold, lying so far from a star that is much smaller and dimmer than the sun.

The faint outer belt could prove useful to astronomers: Studying its shape could yield a better understanding of Proxima b's mass, which is not known very well at the moment, the researchers said.

Read more at Seeker

One of the Oldest and Most Distant Objects in the Universe Has Been Discovered

Distant galaxies are visible in the Hubble Space Telescope's eXtreme Deep Field, which was released in 2012 and based on 22 days of exposure time. The search for extremely distant galaxies continues today.

Astronomers have confirmed the discovery of one the oldest and most distant objects ever known in the universe — a star-forming galaxy 12.8 billion light-years away that started forming within a billion years of the Big Bang that kickstarted everything.

The galaxy, known as G09 83808, was first spotted by the Herschel space telescope, but it only showed up as a blur. The astronomers who made the find wanted more information, so they relayed the data to a team that used the Large Millimeter Telescope, which hosts the largest steerable dish in the world atop the summit of Volcán Sierra Negra, in the Galapagos.

With the 50-meter-diameter LMT dish, astronomers confirmed that G09 83808 is the oldest object ever found by that telescope. Only one other object — a similar galaxy that’s slightly older and more distant — has ever been found by other telescopes.

The research was led by Jorge Zavala, then a graduate student working under LMT director David Hughes. (Hughes is now a postdoctoral research fellow at the University of Texas.) The results were published in the journal Nature Astronomy.

G09 83808 provides almost unique insights into the early days of our universe after the cosmos was formed 13.7 billion years ago.

"Seeing an object within the first billion years is remarkable because the universe was fully ionized, that is, it was too hot and too uniform to form anything for the first 400 million years," said Min Yun, an astrophysicist at the University of Massachusetts Amherst who participated in the research, in a statement. "So our best guess is that the first stars and galaxies and black holes all formed within the first half a billion to one billion years. This new object is very close to being one of the first galaxies ever to form."

Objects such as G09 83808 are difficult to see because they are surrounded by gigantic dust clouds, keeping them out of view from observatories such as the Hubble Space Telescope, which best observes in visible and infrared wavelengths. The LMT is better positioned to look at objects of this kind because it uses millimeter-length wavelengths that can peer through obscuring dust.

Gravitational lensing also helped the astronomers with observations. This phenomenon magnifies light as it passes by a large object, making more distant objects look larger. G09 83808 appeared 10 times brighter and closer than it actually is because there is a large galaxy in between the object and Earth, which helped magnify G09 83808 through gravitational lensing.

LMT will be fully operational this winter and able to peer at more objects that are very old and have a high redshift. Redshift refers to the speed at which the universe expands. More distant objects have a larger redshift.

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Some Butterflies Have Been Fooling Others for 2 Million Years

Several different swallowtail butterfly variations showing mimicry and polymorphism, or different forms of the same species. In the center, a female Papilio polytes that mimics another species, which is toxic to predators.

Red-bodied swallowtail butterflies look so delicate and beautiful that their discoverers named them after flower colors, such as crimson rose. But these eye-catching insects are more sinister than one might imagine.

If an unfortunate predator — even a human — decides to eat one, gagging and severe vomiting may follow. The aftermath is so miserable that victims rarely prey on the butterflies again.

The common Mormon swallowtail butterfly (Papilio polytes), conversely, tastes delicious to birds and other predators. That poses survival challenges for the insects, so females of the species have evolved the ability to look just like toxic red-bodied swallowtails.

Female common Mormons sport different colors, patches, and patterns, though, and only some mimic red-bodied swallowtails. This multi-form phenomenon reminded early entomologists of Mormons who historically practiced polygamy, whereby men may have several wives.

New research on common Mormons and other butterflies published in the journal Nature Communications finds that some populations of these insects have maintained multiple female forms — including mimics — for millions of years.

Understanding the genetic processes that led to these imposters could facilitate research on what are known as “sex-limited” traits and diseases in humans. This means that the conditions tend to affect one sex more than the other.

Lead author Wei Zhang of the University of Chicago’s department of ecology and evolution said the research helps to address classic evolutionary questions and better understand sex-limited traits and diseases in other organisms.

“As far as we know, sex-limited traits and diseases widely exist in many sexually reproducing species as well as in humans, such as baldness and red-green color blindness,” she said.

Common rose swallowtail butterfly

In a prior study, Zhang, senior author Marcus Kronforst, and their team determined that the entire sex-limited mimicry phenomenon in common Mormons and other butterflies is controlled by a single gene named doublesex.

“The doublesex gene is involved in the sex determination of many insects and it gains additional duty in controlling mimicry in some Papilio butterflies,” Zhang said.

The gene actually inverted, or flipped, about 2 million years ago, with this topsy-turvy version dictating wing patterns in females. Doublesex is classified as being a supergene, which usually refers to groups of several tightly linked genes that are inherited together. In this case, however, the supergene is a single multi-tasking gene and not a group.

For the new study, the researchers reconstructed the evolutionary history of the doublesex gene by analyzing whole-genome sequence data from common Mormon butterflies and several similar species to see how they are related to each other and how their copies of the gene compare.

The scientists shared that the most closely related species to the common Mormon butterfly, spangle, is spread across mainland Asia from India to Japan and did not develop mimicry. In this species, both males and females look alike.

Other swallowtail species that spread from the mainland to islands in the Philippines and Indonesia developed three or four distinct forms, a feature known as polymorphism. Other swallowtails spread further into Papua New Guinea and the northeast coast of Australia. But females within those species display only one disguised wing pattern.

Several different swallowtail butterfly variations showing mimicry and polymorphism, or different forms of the same species. Row 1: A female and male Papilio protenor, the species that is closely related to Papilo polytes, the focal of the new study. In P. protenor, males and female look the same and they do not mimic. Row 2: Papilio ambrax, a species where males and females look different and the female is a mimic. In this species, there is no female polymorphism. The new study shows that its evolutionary ancestor was polymorphic, but females lost that trait and only display the mimetic form. Row 3: Polymorphic Papilio polytes, (L-R) A mimetic female form (one of 3 mimetic forms in this species), a non-mimetic female, and the male. Row 4: A distantly related swallowtail, Pachliopta aristolochiae. This is the toxic species that the species in the new study mimic.

The researchers attempted to match the patterns they saw in the genome sequence data to possible explanations for how mimicry developed over time and place in the various butterflies. The evidence supports that once the doublesex gene flipped, a process called balancing selection occurred.

Kronforst said if one mimetic color pattern becomes too common in a population, predators learn that it is palatable because they frequently encounter the mimic and not the toxic model.

“The process can cause the mimetic species to evolve to match multiple models, leading to polymorphism,” he said.

Models, in this case, refer to species that the imposter is mimicking.

Zhang added that various wing forms can also result from members of the same species being geographically widespread, leading insects to mimic different local toxic butterflies.

The researchers observed some butterfly populations maintaining multiple female forms for millions of years, while others lost their original, undisguised form. Historically, the smallest butterfly groups, such as the ones that spread to Australia, lost the polymorphism, allowing genetic drift — essentially genetic variation due to chance — and natural selection to weed out the original form.

Common Mormon female butterfly

The findings reveal the surprising role of chance in both the spread and loss of a beneficial trait, which for certain swallowtails is the mimicry of poisonous butterflies. They also show how powerful a single gene can be.

While humans do not have a doublesex gene, we have numerous other supergenes.

“The supergenes exist in many animals and plants,” Zhang explained. “For example, the human major histocompatibility complex (MHC) contains a group of tightly-linked genes that are functionally related and play roles in the human immune system.”

The basic laws of genetics underlying the evolution of doublesex and MHC supergenes are the same. Understanding these processes can shed light on the evolution of not just beneficial traits, but also deleterious ones.

Read more at Seeker

Fish provide insight into the evolution of the immune system

New findings help to explain why we humans have some immune genes that are almost identical to those of chimpanzees.

New research from the University of East Anglia (UEA), UK, and Dalhousie University, Canada, reveals how immune systems can evolve resistance to parasites.

A study, published in Nature Communications, solves the enigma of how species can adapt and change their immune system to cope with new parasitic threats -- whilst at the same time showing little or no evolutionary change in critical immune function over millions of years.

The findings help to explain why we humans have some immune genes that are almost identical to those of chimpanzees.

Scientists from UEA and Dalhousie University studied how Guppy fish (Poecilia reticulata) adapt to survive by studying their immune genes, known as the Major Histocompatibility Complex or MHC genes.

They found that guppies fine-tune these genes in each location, enabling them to adapt and survive in many different and extreme environments. Despite this adaptation, genes maintained critical function of tens of millions of years.

The discovery could improve scientists' understanding of how related species can adapt and change their immune system to cope with new threats from parasites while simultaneously sharing similar function.

Dr Jackie Lighten from UEA led the study. He said: "Guppies are a small, colourful fish native to South America, Trinidad and Tobago. They are a fantastic model for researching the ecology and evolution of vertebrates.

"MHC genes are an important line of defence in the immune system in vertebrates, including humans. Because parasites evolve quicker than their vertebrate hosts, immune genes need to be highly diverse to keep up with parasites and prevent infections.

"MHC genes produce protein structures that are on the external surface of cells. These genes are diverse and so produce an array of proteins, each of which presents a specific part of a parasite or pathogen that has attempted to infect the body. The specific shape of the protein dictates which parasites it can recognize, and signals to the immune system to prevent infection."

The study looked at MHC genetic variation in 59 guppy populations across Trinidad, Tobago, Barbados, and Hawaii. The authors found hundreds of different immune variants, but these so called 'alleles' appear to be clustered in a smaller number of functional groups or 'supertypes'.

Prof van Oosterhout, also from UEA's School of Environmental Sciences, said: "Each supertype protects the host against a specific group of parasites, and these supertypes were common across populations, and species, irrespective of the location.

"However, the alleles that make up a supertype track the rapid evolution of the parasites, and they too are evolving rapidly. These alleles are largely specific to each population, and they help in the 'fine-tuning' of the immune response to the specific (local) parasites that attack the host in that population."

Before this study, scientists debated how these immune genes can evolve rapidly (which is necessary to keep up with the fast-evolving parasites), whilst also showing little or no evolutionary change in their function over millions of years, as observed between humans and chimpanzees. This study resolves that debate.

Prof Bentzen from Dalhousie University said: "Although this study focused on MHC genes in vertebrates, the evolutionary dynamics described in it likely apply to other gene families, for example resistance genes and those which prevent self-fertilization in plants (self-incompatibility loci) that are caught up in their own evolutionary races."

Read more at Science Daily

Potential 'missing link' in chemistry that led to life on Earth discovered

This study is part of an ongoing effort by scientists around the world to find plausible routes for the epic journey from pre-biological chemistry to cell-based biochemistry.

Chemists at The Scripps Research Institute (TSRI) have found a compound that may have been a crucial factor in the origins of life on Earth.

Origins-of-life researchers have hypothesized that a chemical reaction called phosphorylation may have been crucial for the assembly of three key ingredients in early life forms: short strands of nucleotides to store genetic information, short chains of amino acids (peptides) to do the main work of cells, and lipids to form encapsulating structures such as cell walls. Yet, no one has ever found a phosphorylating agent that was plausibly present on early Earth and could have produced these three classes of molecules side-by-side under the same realistic conditions.

TSRI chemists have now identified just such a compound: diamidophosphate (DAP).

"We suggest a phosphorylation chemistry that could have given rise, all in the same place, to oligonucleotides, oligopeptides, and the cell-like structures to enclose them," said study senior author Ramanarayanan Krishnamurthy, associate professor of chemistry at TSRI. "That in turn would have allowed other chemistries that were not possible before, potentially leading to the first simple, cell-based living entities."

The study, reported in Nature Chemistry, is part of an ongoing effort by scientists around the world to find plausible routes for the epic journey from pre-biological chemistry to cell-based biochemistry.

Other researchers have described chemical reactions that might have enabled the phosphorylation of pre-biological molecules on the early Earth. But these scenarios have involved different phosphorylating agents for different types of molecule, as well as different and often uncommon reaction environments.

"It has been hard to imagine how these very different processes could have combined in the same place to yield the first primitive life forms," said Krishnamurthy.

He and his team, including co-first authors Clémentine Gibard, Subhendu Bhowmik, and Megha Karki, all postdoctoral research associates at TSRI, showed first that DAP could phosphorylate each of the four nucleoside building blocks of RNA in water or a paste-like state under a wide range of temperatures and other conditions.

With the addition of the catalyst imidazole, a simple organic compound that was itself plausibly present on the early Earth, DAP's activity also led to the appearance of short, RNA-like chains of these phosphorylated building blocks.

Moreover, DAP with water and imidazole efficiently phosphorylated the lipid building blocks glycerol and fatty acids, leading to the self-assembly of small phospho-lipid capsules called vesicles -- primitive versions of cells.

DAP in water at room temperature also phosphorylated the amino acids glycine, aspartic acid and glutamic acid, and then helped link these molecules into short peptide chains (peptides are smaller versions of proteins).

"With DAP and water and these mild conditions, you can get these three important classes of pre-biological molecules to come together and be transformed, creating the opportunity for them to interact together," Krishnamurthy said.

Krishnamurthy and his colleagues have shown previously that DAP can efficiently phosphorylate a variety of simple sugars and thus help construct phosphorus-containing carbohydrates that would have been involved in early life forms. Their new work suggests that DAP could have had a much more central role in the origins of life.

"It reminds me of the Fairy Godmother in Cinderella, who waves a wand and 'poof,' 'poof,' 'poof,' everything simple is transformed into something more complex and interesting," Krishnamurthy said.

DAP's importance in kick-starting life on Earth could be hard to prove several billion years after the fact. Krishnamurthy noted, though, that key aspects of the molecule's chemistry are still found in modern biology.

"DAP phosphorylates via the same phosphorus-nitrogen bond breakage and under the same conditions as protein kinases, which are ubiquitous in present-day life forms," he said. "DAP's phosphorylation chemistry also closely resembles what is seen in the reactions at the heart of every cell's metabolic cycle."

Krishnamurthy now plans to follow these leads, and he has also teamed with early-Earth geochemists to try to identify potential sources of DAP, or similarly acting phosphorus-nitrogen compounds, that were on the planet before life arose.

Read more at Science Daily

Mammals Remained in the Shadows Until Dinosaurs Went Extinct

An artist's impression of Mesozoic animals found fossilized in the Kayenta rock formation. It depicts Dilophosaurus (dinosaur) at the back, Kayentatherium (Mesozoic mammal) in the center, and Kayentachelys (Mesozoic turtle) at the front.

Not all was doom and gloom after dinosaurs went extinct around 65 million years ago. Before that time, when Tyrannosaurus rex and other large predators lurked, mammals were mostly small and scrappy creatures of the night.

After non-avian dinosaurs died out, mammals began to come out of the shadows. New research published in the journal Nature Ecology & Evolution reports that mammals only started to become diurnal — active during the day — when dinosaurs were gone for good.

“The first mammals who became active in the daytime may have done so for a variety of reasons, such as reduced predation risk in the daytime or increased ecological opportunity in the absence of dinosaurs,” lead author Roi Maor of Tel Aviv University told Seeker.

Maor and his colleagues Tamar Dayan, Henry Ferguson-Gow, and Kate Jones had a daunting task: The fossil record reveals little about the activity patterns of animals. Dayan said researchers observe a living mammal to see if it is active at night or in the day. But, he added fossil evidence from mammals often suggests that they were nocturnal even if they were not.

“Many subsequent adaptations that allow us to live in daylight are in our soft tissues,” Dayan said.

Recreation of dinosaur extinction at the Deccan Traps in Western Ghats, India

To get around that problem, the researchers analyzed data from 2,415 species of mammals alive today, their relatedness to other existent mammal species, and their connections to known ancestors. They then used computer algorithms to reconstruct the likely activity patterns of the mammals that lived in the past.

Several theories exist that seek to explain the origins of mammals and their family trees. The researchers, therefore, constructed two different mammalian family trees portraying alternative timelines for the evolution of mammals.

The results show the same phenomenon: Mammals switched to daytime activity shortly after the dinosaurs disappeared.

The scientists found that the ancestors of simian or higher primates, such as monkeys, gorillas and humans, were among the first to give up nocturnal activity.

The discovery helps to explain why these primates are the only mammals that evolved adaptations to seeing well in daylight. This is largely because all other mammals lack a fovea, which is a small depression in the retina of the eye where visual acuity is highest.

“No mammals, except monkeys and apes, have more than two types of cones — sensitive to short and long light wavelengths — in their retinae, and their vision has been compared to a red-green colorblind human,” Maor said.

According to the “nocturnal bottleneck hypothesis,” Maor said mammals co-existed alongside dinosaurs thanks to the segregation of the two groups’ ecological niches along a temporal day–night axis.

In short, the first mammals essentially evolved to avoid diurnal dinosaurs.

“It follows that when dinosaurs went extinct, they freed niche space to be taken by other species, including mammals, for which the daytime would have been a novel niche,” Maor said. “According to ecological theory, entering a novel niche may allow a species to evade predators and-or competitors present in its original niche, giving it an advantage that may lead to evolutionary success.”

Recreation of Tyrannosaurus rex

Maor stopped short at saying that this advantage might have given the ancestors of humans an evolutionary edge, such as setting the stage for the later emergence of our relatively big brains and sharp eyesight during daylight hours. The visual acuity and color perception of healthy humans and other simians is comparable to those of diurnal reptiles and birds — animal groups that never left the daytime niche.

It is important to note that not all living primates are diurnal. Slow lorises, many lemurs, and other primates are strictly nocturnal. In fact, diurnal species are still a minority within all mammals.

“In our data set, there are about 26 percent diurnal species and 60 percent nocturnal ones, and the proportions among all mammals would be very similar,” Maor explained.

Read more at Seeker

A Porous Core on Saturn's Icy Moon Enceladus May Fuel Its Mysterious Geysers

Artist's concept of the Cassini spacecraft flying through the plumes of Enceladus.

In 2005, NASA’s Cassini spacecraft identified geysers on Saturn’s moon Enceladus that were blasting plumes of ice and vapor into space. Now a new study suggests that the secret to these geysers lies in Enceladus’s core  —  and that related hydrothermal activity may have existed long enough to allow life to arise on the icy moon.

Enceladus is famous for displaying dozens of erupting geysers at the south pole, in view of the Cassini spacecraft, which was in the system between 2004 and 2017.

Scientists originally theorized that the tidal forces of Saturn on the small moon caused the dozens of erupting geysers around its south pole, but later calculations testing this idea showed that the water would have frozen over within 30 million years. (The solar system is over 4.6 billion years old.)

To keep the water flowing, “an abnormally high heat power (more than 20 billion watts) is required, as well as a mechanism to focus endogenic [below-surface] activity at the south pole,” the authors of the new study write in the journal Nature Astronomy. The research was led by Gaël Choblet, a University of Nantes researcher in France who specializes in planetary interiors.

The research team suggests that the additional heat could be generated from tidal friction inside the core, which they described as rocky and unconsolidated, meaning that the core is loosely held together. This porous core allows water to move up in narrow, hot columns that burst through hotspots on the seafloor. The model further shows that the activity could continue for at least a few tens of millions of years, and perhaps billions of years.

“The release of heat in narrow regions favors intense interaction between water and rock, and the transport of hydrothermal products from the core to the [water] plume sources,” the authors write. “We are thus able to explain the main global characteristics of Enceladus: global ocean, strong dissipation, reduced ice-shell thickness at the south pole, and seafloor activity.”

The authors say that Enceladus’s core is likely a metal-rock nucleus with a lot of water-filled areas, as well as many iron-bearing hydrated materials; the abundance of these materials, they added, would hint as to how much water is in the core. The models included information from parameters such as the libration (oscillation or wobbling) of Enceladus that was detected by Cassini, observed sediments flowing underneath glaciers, and loading tests on granular materials.

These findings have implications for potential life on Enceladus. Cassini’s detection of hydrogen gas in one of the moon’s plumes fueled the idea that hydrothermal vents lie deep inside the moon’s subsurface ocean. They might possibly resemble those that are found on Earth, where chemical reactions could theoretically have produced the beginnings of microbial life on our planet. If so, then similar hydrothermal activity taking place on Enceladus for billions of years may have given potential life an opportunity to evolve on the icy moon.

Read more at Seeker

The Hole in the Ozone Layer Is at It's Smallest in Nearly Three Decades

Ozone Hole

Higher temperatures over Antarctica this year shrank the hole in the ozone layer to the smallest it's been since 1988.

The ozone hole is a depletion of ozone gas (O3) in the stratosphere above Antarctica. The three-oxygen molecule is toxic at ground level, but high in the atmosphere, it deflects dangerous ultraviolet rays from reaching Earth's surface.

In 1985, scientists first detected the hole in the ozone layer and realized it was being caused by man-made chlorine and bromine, often found in chlorofluorocarbons (CFCs), compounds used as refrigerants. In 1987, the Montreal Protocol initiated the phase-out of these chemicals. As they gradually leave the atmosphere, the ozone hole will heal, and scientists expect it to return to 1980s size by 2070.

Natural variability affects this healing year-to-year, however.

"The Antarctic ozone hole was exceptionally weak this year," Paul Newman, chief scientist for Earth Sciences at NASA's Goddard Space Flight Center in Greenbelt, Maryland, said in a statement. "This is what we would expect to see given the weather conditions in the Antarctic stratosphere."

Weather and ozone

In the upper atmosphere, CFCs break apart, freeing chlorine to react with ozone molecules, a reaction that creates oxygen and chlorine monoxide. Similar reactions occur with bromine. Polar stratospheric clouds, which form in frigid temperatures, speed up this process by providing surfaces for the reactions to occur on. That's why the ozone hole worsens in the Southern Hemisphere winter.

The hole in Earth's protective ozone layer that forms over Antarctica each September was the smallest seen since 1988, according to NASA and NOAA.

Higher temperatures in the stratosphere, on the other hand, allow ozone to remain more stable in the atmosphere, meaning they keep the ozone hole smaller on a year-to-year basis. This year on Sept. 11, NASA measured the maximum extent of the hole at 7.6 million square miles (19.6 million square kilometers), 2.5 times the size of the United States.

That was smaller than in 2016, when the maximum extent was 8.9 million square miles (22.2 million square km), also a below-average size. According to NASA, the average maximum extent of the ozone hole since 1991 has hovered at about 10 million square miles (25.8 million square km).

Historic high

However, scientists said that two years of lower-than-usual ozone hole extent isn't a sign that the ozone layer is healing faster than expected. Instead, it's a side effect of the Antarctic vortex — a low-pressure system that rotates clockwise above the southernmost continent — undergoing a few years of instability and warmth, which prevented the proliferation of polar stratospheric clouds.

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Hubble sees nearby asteroids photobombing distant galaxies

Asteroid Trails Streak Across This Deep-Space View of Thousands of Galaxies. Photobombing asteroids from our solar system have snuck their way into this deep image of the universe taken by NASA's Hubble Space Telescope. These asteroids are right around the corner in astronomical terms, residing roughly 160 million miles from Earth. Yet they've horned their way into this picture of thousands of galaxies scattered across space and time at inconceivably farther distances.

Like rude relatives who jump in front your vacation snapshots of landscapes, some of our solar system's asteroids have photobombed deep images of the universe taken by NASA's Hubble Space Telescope. These asteroids reside, on average, only about 160 million miles from Earth-right around the corner in astronomical terms. Yet they've horned their way into this picture of thousands of galaxies scattered across space and time at inconceivably farther distances.

This Hubble photo of a random patch of sky is part of a survey called Frontier Fields. The colorful image contains thousands of galaxies, including massive yellowish ellipticals and majestic blue spirals. Much smaller, fragmentary blue galaxies are sprinkled throughout the field. The reddest objects are most likely the farthest galaxies, whose light has been stretched into the red part of the spectrum by the expansion of space.

Intruding across the picture are asteroid trails that appear as curved or S-shaped streaks. Rather than leaving one long trail, the asteroids appear in multiple Hubble exposures that have been combined into one image. Of the 20 total asteroid sightings for this field, seven are unique objects. Of these seven asteroids, only two were earlier identified. The others were too faint to be seen previously.

The trails look curved due to an observational effect called parallax. As Hubble orbits around Earth, an asteroid will appear to move along an arc with respect to the vastly more distant background stars and galaxies.

This parallax effect is somewhat similar to the effect you see from a moving car, in which trees by the side of the road appear to be passing by much more rapidly than background objects at much larger distances. The motion of Earth around the Sun, and the motion of the asteroids along their orbits, are other contributing factors to the apparent skewing of asteroid paths.

All the asteroids were found manually, the majority by "blinking" consecutive exposures to capture apparent asteroid motion. Astronomers found a unique asteroid for every 10 to 20 hours of exposure time.

The Frontier Fields program is a collaboration among NASA's Great Observatories and other telescopes to study six massive galaxy clusters and their effects. Using a different camera, pointing in a slightly different direction, Hubble photographed six so-called "parallel fields" at the same time it photographed the massive galaxy clusters. This maximized Hubble's observational efficiency in doing deep space exposures. These parallel fields are similar in depth to the famous Hubble Deep Field, and include galaxies about four-billion times fainter than can be seen by the human eye.

This picture is of the parallel field for the galaxy cluster Abell 370. It was assembled from images taken in visible and infrared light. The field's position on the sky is near the ecliptic, the plane of our solar system. This is the zone in which most asteroids reside, which is why Hubble astronomers saw so many crossings. Hubble deep-sky observations taken along a line-of-sight near the plane of our solar system commonly record asteroid trails.

Read more at Science Daily

Newly discovered orangutan species is 'among the most threatened great apes in the world'

Photo of a Pongo tapanuliensis skull.

Scientists have long recognized six living species of great ape aside from humans: Sumatran and Bornean orangutans, eastern and western gorillas, chimpanzees, and bonobos. But researchers reporting in Current Biology on November 2 have now made it seven, based on a collection of evidence showing that an isolated population of orangutans living in Sumatra is actually its own unique species. They've named the new species the Tapanuli orangutan (Pongo tapanuliensis).

Unfortunately, the researchers say, there are only about 800 Tapanuli orangutans left. Those that remain are also under threat from loss of lowland habitat and hunting, which makes this newly discovered species among the most threatened great ape species in the world.

"It isn't an everyday event that we find a new species of great ape, so indeed the discovery is very exciting," said Michael Krutzen of the University of Zurich in Switzerland, senior author of the study.

"Great apes are among the best-studied species in the world," added Erik Meijaard of the Australian National University. "If after 200 years of serious biological research we can still find new species in this group, what does it tell us about all the other stuff that we are overlooking: hidden species, unknown ecological relationships, critical thresholds we shouldn't cross? Humans are conducting a vast global experiment, but we have near-zero understanding of what impacts this really has, and how it could ultimately undermine our own survival."

The new orangutan species lives in the Batang Toru area in North Sumatra, Indonesia. While there had been rumors, no one was sure that this population of orangutans existed until 1997. They live south of what had been the known range for Sumatran orangutans.

Earlier studies suggested that the group differed from other orangutans behaviorally and at the genetic level, but it wasn't clear that those differences were enough to support its designation as a new species. The breakthrough came in 2013, when the research team including Meijaard got access to a skeleton belonging to a Batang Toru orangutan killed in a human-animal conflict. Careful studies of the animal revealed consistent differences in its skull and teeth.

A sophisticated analysis of 37 orangutan genomes now shows that the deepest split in the evolutionary history of living orangutans occurred more than three million years ago, between the Batang Toru population and Bornean orangutans to the north of Lake Toba. Bornean and Sumatran orangutans separated only much later, less than 700,000 years ago. Behavioral and ecological evidence lends further support for the notion that the orangutans living in Batang Toru are a separate species, the researchers said.

"The Batang Toru orangutans appear to be direct descendants of the initial orangutans that had migrated from mainland Asia, and thus constitute the oldest evolutionary line within the genus Pongo," said Alexander Nater, also of the Unversity of Zurich. "The Batang Toru population was connected to populations to the north until 10,000 or 20,000 years ago, after which it became isolated."

The findings mean that there are now 800 fewer Sumatran orangutans than previously thought. The Tapanuli orangutans are also severely threatened by hunting and the proposed development of a hydroelectric dam that would flood large parts of their best habitat if implemented. That's especially discouraging given that previous analyses suggest a mortality rate of less than one percent per year would still be enough to drive the Tapanuli orangutans extinct.

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