вторник, 30 июля 2019 г.

Places we once called home

There was a time when the laughter of Stone Age children filled the Sibudu Cave. About 64 000 years ago, a child was part of a hunter-gatherer family that took temporary shelter in this cave, which lies close to the KwaZulu-Natal town of KwaDukuza.

Places we once called home
Klipdrift Cave and Klipdrift Shelter, located in the De Hoop Nature Reserve, southern Cape, South Africa, have
elicited findings from roughly 65 000 years ago to 59 400 years ago, including a hominin molar, floral
remains, and more than 95 pieces of eggshell engraved with diverse, abstract patterns
[Credit: Wits University]

When this child died, it didn’t leave its bones in the cave for discovery by archaeologists of the future—the only thing left behind was a milk tooth. In modern times, the mythological tooth fairy whisks away children’s teeth, but we don’t know what the rituals were back then.

Professor Lyn Wadley, archaeologist in the School of Geography, Archaeology and Environmental Studies at Wits, is thankful that this tooth—and those of other children—ended up on the cave floor, because they reveal just how much humans have changed since we gave up our hunter-gatherer ways.

Teeth-bricks for tooth fairies

«The interesting thing about the teeth is that we know this is a home-base, because there were children there, and that is quite nice,» says Wadley. «But the [research] papers also suggest that the teeth were perhaps a little bit larger than the teeth of children today. So maybe the people were a little more robust.» These children perhaps had access to better diets than we have today.

«A lot of people have pointed out that moving to the diet that farming people had was not necessarily improving the health of people. There are higher carbohydrates compared to protein, and with it comes poorer tooth quality and poorer bone quality,» says Wadley.

«Part of the reason why hunter-gatherers had a better diet was not because of what they were eating, but the fact that groups were smaller and this meant that people had better access to quality plant foods.»

Cave sites like Sibudu are providing scientists with a peek into what our earliest homes looked like. These glimpses give archaeologists not only a better understanding of how our ancestors lived, but also how we evolved into the species we are today.

No fixed abode

From the deep past, scientists are uncovering the stuff that makes us human—from forward planning, to the very beginnings of art. One of these discoveries is that our ancestors were not homebodies. We were wanderers who kept our stays short.

At Blombos Cave in the southern Cape, Professor Christopher Henshilwood and his team have been sifting through the leftovers of these brief visits that go back over 100 000 years. Henshilwood holds the DST/NRF SARChI Chair in The Origins of Modern Human Behaviour at Wits University and is the Director of the Centre for Early Sapiens Behaviour (SapienCE), a new Centre of Excellence at the University of Bergen in Norway.

«We think that Blombos, at some stages, was occupied for just one night. We are seeing what looks like a ghost of a visit. You find a few shellfish, a tiny little fire and almost nothing else. And then there is nothing after that,» says Henshilwood.

The world’s first hashtag

Some of the discoveries at Blombos have advanced our insight into early human cognitive development.

Last year, Henshilwood and his team revealed a silcrete (hardened mineral crust) flake to the world that had six crosshatched lines on it—much like a hashtag. A human, using an ochre crayon, 73 000 years ago, had drawn these lines.

It took two years of scientific testing to come to the conclusion that this is the earliest example of a drawing, says Henshilwood.

Places we once called home
Credit: Wits University

Even this long ago, at Blombos Cave and Klipdrift Shelter, another of the sites excavated by Henshilwood’s team, you can see that people bring to the site what they need to carry out a particular task. «These people are capable of planning, they have templates or recipes in their heads, for what they need in the cave,» says Henshilwood. «This is one of the markers of behavioural modernity.»

When that artist made that drawing on that piece of silcrete, he or she would have been one of only about 10 000 humans living in the whole of Africa.

There are other artifacts left at these temporary homes that point to our ancestors being highly intelligent problem-solvers. At Border Cave on the Swaziland border, Wadley and Dr. Lucinda Backwell found traces of poison on a thin wooden stick that dates back at least 20 000 years. The poison is thought to have been used on arrows.

Homemakers and hunter-gatherers

Wadley believes that snares were also used by the people who periodically made Sibudu their home. But it is the presence of buffalo bones in the cave that points to team work, which would have probably included women.

«If you look at your typical hunter-gatherer group—let us say there are 60 people—more than half of those are going to be children who wouldn’t take part in the hunt. Then you have some old people. So if you break down the demographics, you might only end up with 10 able-bodied male hunters,» says Wadley. «If you want to manage a dangerous animal hunt, you are going to have to bring in the women too, even if they are just beaters.»

What archaeologists are rarely seeing is evidence of other homes away from the caves and rock shelters. These rudimentary shelters would have been where our ancestors slept for a couple of nights before moving on.

Home security

Professor Robert Thornton, social anthropologist in the School of Social Sciences at Wits, says that three basic needs would have driven early humans into utilizing and making shelters. «Our earliest habitats were primarily designed to keep our food safe, secondarily to keep the goggas [insects] and other stuff away, and finally for climate control. But before that, it was important to keep your view open,» he says.

«People imagined that early man lived in caves, or they had to have four walls around them, but that is one of the worst things you can do, because you cannot see the rest of your environment. You want to be in the open, you want to see 360 degrees, particularly when there are big cats around.»

But it is in the caves where the treasures lie. It is here that the artifacts are best preserved, and where they accumulate in layers of earth that sometimes stretch back hundreds of thousands of years.

At Blombos, Henshilwood hopes he might one day find the rest of that silcrete flake that would reveal more of that earliest drawing.

But there are more artifacts to be found in places we once called home that will give us insight into a time when humans first began to act and think like we do.

Author: Shaun Smillie | Source: Wits University [July 24, 2019]



Shining a new light on the evolution of supernovae

A research team led by UNSW Canberra scientist Ivo Seitenzahl is shining a new light on the evolution of supernovae—a hotly contested topic amongst astrophysicists.

Shining a new light on the evolution of supernovae
Credit: European Southern Obervatory

In a new paper published by Physical Review Letters, the team explains how they discovered optical emission from the shocked ejecta of thermonuclear supernova remnants.

«A supernova is essentially an exploding star,» Dr. Seitenzahl said. «Not all stars will explode as a supernova to end their lives, as many low mass stars will simply turn into white dwarf stars and cool and fade away without an explosion.»

Dr. Seitenzahl’s research concerns thermonuclear or «Type Ia» supernovae. When this type of supernova explodes, it flings the elements that are produced in the explosion back into the galaxy. These elements mix with the gas present in the galaxy.

Out of this gas, new stars (with their planetary systems) form. Most of the manganese, iron and nickel on Earth was made in these explosions more than five billion years ago.

Shining a new light on the evolution of supernovae
Optical emission images of the SNRs 0519-69.0 (left) and 0509-67.5 (right), as obtained through
the “supernova remnant tomography” technique developed by Seitenzahl et al.
[Credit: UNSW Canberra]

The research team’s discovery reveals optical emission from the supernova’s ejected elements (atoms) and a careful analysis of the light emitted allows for a first direct determination of the shock velocity.

«Previously, people had seen optical emission from the shocked gas of the interstellar medium,» Dr. Seitenzahl said. «Now we are seeing emission from the iron-rich ejecta that was freshly synthesized in the explosion.»

The kind of stars that explode as a Type Ia supernova and their evolution prior to explosion is fiercely debated in the world of astrophysics.

Dr. Seitenzahl said the team’s discovery provides a new physical emission mechanism for the study of these exploding stars.

«I really believe our result is one of the most important new discoveries in supernova and supernova remnant research in the past decade,» Dr. Seitenzahl said.

Source: UNSW Canberra [July 25, 2019]



New discovery sheds light on how planets form

Researchers at Dartmouth College have discovered a planet orbiting one of the brightest young stars known, according to a study published in the journal The Astrophysical Journal Letters. Aged at approximately 45 million years old, the star and its planet could provide valuable information on how planetary bodies form.

New discovery sheds light on how planets form
An artist’s rendering of a gas giant in a binary stellar system
[Credit: NASA/JPL-Caltech/T. Pyle]

Known as an exoplanet because it is outside of the solar system, the planet was found as part of NASA’s Transiting Exoplanet Survey Satellite (TESS) mission. While thousands of exoplanet discoveries have already been made, only a handful have been discovered circling relatively young stars.

The exoplanet observed in the Dartmouth research — known as DS Tuc Ab — can be considered a «pre-teen» in planetary time. The planet is no longer growing, but, because of its young age, it is still undergoing rapid changes like losing atmospheric gas as a result of the radiation coming from its host star.

Planets can take millions or billions of years to reach maturity. Since that process cannot be observed in real time, researchers are searching for planets around young stars to catch the process in action and learn how planets form and evolve.

«One of the overall goals of astronomy is understanding the big picture of how we got here, how solar systems and galaxies take shape and why,» said Elisabeth Newton, an assistant professor of physics and astronomy at Dartmouth. «By finding solar systems that are different from our own — especially young ones — we can hope to learn why Earth and our own solar system evolved in the ways that they did.»

DS Tuc Ab is about six times the size of Earth, between the sizes of Neptune and Saturn. Given the size, it likely has a composition similar to that of the giant planets in our solar system. The exoplanet has two suns and makes one full orbit around its main star in just eight days.

The planet was first observed by NASA satellite in November of 2018 and was confirmed by the Dartmouth team in March using data from NASA’s Spitzer Space Telescope and other ground- and space-based observatories, such as the South African Large Telescope (SALT).

New discovery sheds light on how planets form
Data on the brightness of a young star led to the discovery of exoplanet DS Tuc Ab. Red arrows mark ‘transits’
where the planet crossed between Earth and the planet’s host star. The large, smooth variations
are caused by the star, a result of its youth [Credit: Elisabeth Newton]

The planet is about 150 light years away from Earth. Each light year is a distance of just under 6 trillion miles.

«We were really excited when we confirmed this discovery because the planet orbits such a bright, well-known young star. Our whole team worked together to learn everything we could about this solar system,» said Newton, who led a team of scientists from the University of North Carolina at Chapel Hill, the University Texas at Austin, and other research centers from around the world.

NASA’s TESS mission is looking for planets around nearby stars using the transit method. The approach detects when light is blocked as a planet passes between Earth and the planet’s host star. Researchers then review observations from other telescopes to confirm the discovery.

«The star’s brightness lets us study the planet in detail because the more photons you have the better statistics you have. A discovery of this sort with such a unique age and an unusual planet size would not be possible without TESS,» said Newton.

Planets are larger when first formed and are thought to become smaller over time as they cool and lose atmosphere. Because this planet is still forming, the team hopes to detect atmosphere evaporation in action. Understanding this process could help researchers predict what might happen to the exoplanet over the next billions of years and can also be used to understand how atmospheric escape might have affected older planets, including Earth.

«We hope that by seeing this planet’s atmosphere, we can provide a snapshot of what planets look like at a young age,» said Newton.

The TESS satellite was launched on April 18, 2018. According to NASA, the TESS mission will survey 200,000 of the brightest stars near the sun to search for transiting exoplanets, including those that could support life.

While the research team knows the size of DS Tuc Ab, the overall mass is not known. This limits what the team can currently tell about planet’s density and composition. Thanks to the star’s brightness, future investigations could measure the planet’s mass or determine what molecules are present in its atmosphere.

Source: Dartmouth College [July 25, 2019]



Revolutionary method could bring us much closer to the description of hyperdiverse faunas

Two hundred and sixty-one years ago, Linnaeus formalized binomial nomenclature and the modern system of naming organisms. Since the time of his first publication, taxonomists have managed to describe 1.8 million of the estimated 8 to 25 million extant species of multicellular life, somewhere between 7% and 22%. At this rate, the task of treating all species would be accomplished sometime before the year 4,000. In an age of alarming environmental crises, where taking measures for the preservation of our planet’s ecosystems through efficient knowledge is becoming increasingly urgent, humanity cannot afford such dawdling.

Revolutionary method could bring us much closer to the description of hyperdiverse faunas
This is a lateral image of one of the hundreds of undescribed species of Zelomorpha
[Credit: Michael Sharkey]

«Clearly something needs to change to accelerate this rate, and in this publication we propose a novel approach that employs only a short sequence of mitochondrial DNA in conjunction with a lateral image of the holotype specimen,» explain the researchers behind a new study, published in the open-access journal Deutsche Entomologische Zeitschrift (DEZ).

In standardized practices, it is required that experts conduct plenty of time- and labor-consuming analyses, in order to provide thorough descriptions of both the morphology and genetics of individual species, as well as a long list of characteristic features found to differentiate each from any previously known ones. However, the scientists argue, at this stage, it is impossible to pinpoint distinct morphological characters setting apart all currently known species from the numerous ones not yet encountered. To make matters worse, finding human and financial resources for performing this kind of detailed research is increasingly problematic.

This holds especially true when it comes to hyperdiverse groups, such as ichneumonoid parasitoid wasps: a group of tiny insects believed to comprise up to 1,000,000 species, of which only 44,000 were recognised as valid, according to 2016 data. In their role of parasitoids, these wasps have a key impact on ecosystem stability and diversity. Additionally, many species parasitise the larvae of commercially important pests, so understanding their diversity could help resolve essential issues in agriculture.

Meanwhile, providing a specific species-unique snippet of DNA alongside an image of the specimen used for the description of the species (i.e. holotype) could significantly accelerate the process. By providing a name for a species through a formal description, researchers would allow for their successors to easily build on their discoveries and eventually reach crucial scientific conclusions.

«If this style were to be adopted by a large portion of the taxonomic community, the mission of documenting Earth’s multicellular life could be accomplished in a few generations, provided these organisms are still here,» say the authors of the study.

To exemplify their revolutionary approach, the scientists use their paper to also describe a total of 18 new species of wasps in two genera (Zelomorpha and Hemichoma) known from Area de Conservacion Guanacaste, Costa Rica. Currently, the team works on the treatment of related species, which still comprise only a portion of the hundreds of thousands that remain unnamed.

Source: Pensoft Publishers [July 25, 2019]



Hidden genetic variations power evolutionary leaps

Laboratory populations that quietly amass ‘cryptic’ genetic variants are capable of surprising evolutionary leaps, according to a paper in the journal Science. A better understanding of cryptic variation may improve directed evolution techniques for developing new biomolecules for medical and other applications.

Hidden genetic variations power evolutionary leaps
Laboratory populations that quietly amass «cryptic» genetic variants are capable
of surprising evolutionary leaps [Credit: Vladimir Timofeev, iStock]

Genetic variation—that is, accumulated mutations in the DNA—is the fuel for all evolutionary change: the more genetic variation, the faster evolution works and the more possibilities for novel adaptive solutions.

But one kind of genetic variation—hidden, or «cryptic,» variation— doesn’t alter the appearance or behavior of an organism in its usual environment.

«It’s an underappreciated kind of genetic variation,» says corresponding author Andreas Wagner, an evolutionary biologist at the University of Zurich and external professor at the Santa Fe Institute, «and it plays an important role in evolution.»

Previous work has shown that cryptic variation in natural populations promotes rapid evolutionary adaptation. But the underlying molecular mechanisms were unclear.

To explore those mechanisms, Wagner’s team worked with populations of the gut bacterium E. coli that carried a plasmid with a gene for a yellow fluorescent protein (YFP). The team designed a two-stage experiment. In stage 1, they used mutagenic PCR to increase variation in the YFP gene. Simultaneously, they selected for a narrow range of yellow fluorescence. Any bacteria not sufficiently yellow were excluded, a process called ‘stabilizing selection.’ In this way, they built up deep stores of cryptic genetic variation without altering the yellow color of the YFP protein.

During stage 2, the team changed the selection rules and began selecting for E. coli that fluoresced in the green part of the spectrum (‘directional selection’). They also introduced control populations of E. coli that lacked enhanced cryptic variation in YFP. The E. coli cell lines with stores of cryptic variation evolved green fluorescent protein (from YFP genes) that were both greener and genetically more diverse than any produced by the control E. coli lineages.

In the experiment, says co-author Joshua Payne (ETH Zurich), cryptic variation did more than drive evolutionary adaptation faster. Cell lines with deep reserves of cryptic variation evolved greener YFP proteins, forms of the protein that were inaccessible to regular bacteria, and they evolved by multiple unique routes not available to regular E. coli.

Current laboratory directed evolution often leads to the same evolutionary outcomes each time. The new work shows how amassing cryptic variation can open doors to otherwise inaccessible regions of protein sequence space, says first author Jia Zheng, a postdoctoral researcher at the University of Zurich.

In the wild, cryptic variation helps fish adapt to life in caves. In the lab, cryptic variation might help a biomolecule bind a new receptor. «Our work can help develop new directed evolution strategies to find innovative biomolecules for biotechnological and medical applications,» says Zheng.

Like a fat savings account, cryptic variation is a store of variation that becomes available in an emergency to fuel rapid evolutionary change critical to the survival of a lineage and useful for molecular biologists.

Source: Santa Fe Institute [July 25, 2019]



2019 July 30 Star Forming Region NGC 3582 without Stars Image…

2019 July 30

Star Forming Region NGC 3582 without Stars
Image Credit & Copyright: Andrew Campbell

Explanation: What’s happening in the Statue of Liberty nebula? Bright stars and interesting molecules are forming and being liberated. The complex nebula resides in the star forming region called RCW 57, and besides the iconic monument, to some looks like a flying superhero or a weeping angel. By digitally removing the stars, this image showcases dense knots of dark interstellar dust, fields of glowing hydrogen gas ionized by these stars, and great loops of gas expelled by dying stars. A detailed study of NGC 3576, also known as NGC 3582 and NGC 3584, uncovered at least 33 massive stars in the end stages of formation, and the clear presence of the complex carbon molecules known as polycyclic aromatic hydrocarbons (PAHs). PAHs are thought to be created in the cooling gas of star forming regions, and their development in the Sun’s formation nebula five billion years ago may have been an important step in the development of life on Earth.

∞ Source: apod.nasa.gov/apod/ap190730.html

‘King Doniert’s Stone’ Ancient Cross Fragments, Cornwall, 24.7.19.The...

‘King Doniert’s Stone’ Ancient Cross Fragments, Cornwall, 24.7.19.

The stone fragments seem to record the death of King Doniert, one of the last recorded kings of Cornwall who died by drowning at some point in the 7th century CE.

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‘Long Tom’s Cross’ Ancient Cross, Liskeard, Cornwall, 24.7.19.An...

‘Long Tom’s Cross’ Ancient Cross, Liskeard, Cornwall, 24.7.19.

An ancient cross possibly carved out from a prehistoric standing stone.

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NASA’s Spacecraft Atmosphere Monitor Goes to Work Aboard the International Space...

ISS — International Space Station logo.

July 29, 2019

NASA is validating modern crew health technologies aboard the International Space Station before sending astronauts on a series of Artemis expeditions to orbit and land on the Moon, beginning in 2024. One of the most important conditions associated with crew health during spaceflight is air quality. Trace gas contaminants in the crew environment can have effects ranging from immediate discomfort to long-term health conditions.

Enter NASA’s Spacecraft Atmosphere Monitor (S.A.M.), which flew as payload aboard the SpaceX Dragon cargo spacecraft that launched on July 25 from Cape Canaveral Air Force Station in Florida.

Currently, atmosphere quality aboard the space station is assessed by periodic sampling and ground-based analysis using sophisticated instruments. Since samples cannot be returned to Earth during future exploration missions, a complement of smaller and more reliable instruments such as S.A.M. becomes essential to monitor the crew environment.

Image above: S.A.M is one of the smallest (mass and power) autonomous GCMS instruments ever built and will continuously monitor the major components found in air in real-time.
Image Credit: NASA.

“Monitoring the spacecraft cabin atmosphere and maintaining safe air quality is important to protecting astronaut health,” said Jitendra Joshi, senior technical advisor at NASA Headquarters. “S.A.M has the ability to immediately detect trace contaminants that pose potential threats to crewmembers’ well-being, which is critical for future human spaceflight missions, especially missions to the Moon and Mars, when we won’t have the benefit of sending samples back to Earth.”

Meet S.A.M.

This type of analysis typically requires the use of a gas chromatograph mass spectrometer (GCMS) instrument which separates, identifies and quantifies complex mixtures of chemicals. S.A.M is one of the smallest autonomous GCMS instruments ever built. GCMS is considered the “gold standard” in substance identification because of its ability to detect and positively identify the presence of trace amounts of a particular substance and allows for a much finer degree of substance identification.

The current version of S.A.M. will continuously monitor the major components found in air — oxygen, carbon dioxide, nitrogen and methane, and humidity levels in real-time. The next version of S.A.M. is being developed to measure the full complement of atmospheric including trace gases.

S.A.M.’s compact design allows for it to perform instrument science operations inside the space station’s EXPRESS (EXpedite the PRocessing of Experiments to Space Stations) Racks. EXPRESS Racks are multipurpose payload rack systems that store and support research. S.A.M.’s size also allows it to be easily deployed throughout the various nodes of the space station to monitor different astronaut environments and activities, such as exercise and sleep.

Image above: S.A.M.’s compact design allows for easy deployment throughout ISS to monitor different astronaut environments and activities, such as exercise and sleep. Image Credit: NASA.

While on station, information concerning S.A.M.’s technical performance as well as health and operational status, will constantly be routed through the Huntsville Operations Support Center (HOSC) at Marshall Space Flight Center in Alabama. The HOSC will then route the data to the operation team at NASA’s Jet Propulsion Lab’s (JPL) Earth Science Mission Operations Center.

While the S.A.M. is fully autonomous and does not require data processing for issuing reports concerning air quality elements, JPL scientists will have the ability to closely analyze the data for anomalies and other unexpected findings.

S.A.M. was developed by JPL with support from NASA’s Advanced Exploration Systems (AES) division within the Human Exploration and Operations Mission Directorate in Washington. S.A.M is a technology demonstration and is slated to begin work aboard the space station on July 30.

NASA’s human lunar exploration plans are based on a two-phase approach: the first is focused on speed – landing on the Moon within five years, while the second will establish a sustained human presence on and around the Moon by 2028. The agency will use what we learn on the Moon to prepare for the next giant leap – sending astronauts to Mars.

To learn more about Space Station research and technology visit:   

International Space Station (ISS): https://www.nasa.gov/mission_pages/station/main/index.html
For more information about NASA’s Moon to Mars exploration plans, visit:

Images (mentioned), Text, Credits: NASA/Denise Hill.

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NASA’s TESS Mission Scores ‘Hat Trick’ With 3 New Worlds

NASA — Transiting Exoplanet Survey Satellite (TESS) logo.

July 29, 2019

NASA’s newest planet hunter, the Transiting Exoplanet Survey Satellite (TESS), has discovered three new worlds — one slightly larger than Earth and two of a type not found in our solar system — orbiting a nearby star. The planets straddle an observed gap in the sizes of known planets and promise to be among the most curious targets for future studies.

TESS Object of Interest (TOI) 270 is a faint, cool star more commonly identified by its catalog name: UCAC4 191-004642. The M-type dwarf star is about 40% smaller than the Sun in both size and mass, and it has a surface temperature about one-third cooler than the Sun’s. The planetary system lies about 73 light-years away in the southern constellation of Pictor.

Image above: This infographic illustrates key features of the TOI 270 system, located about 73 light-years away in the southern constellation Pictor. The three known planets were discovered by NASA’s Transiting Exoplanet Survey Satellite through periodic dips in starlight caused by each orbiting world. Insets show information about the planets, including their relative sizes, and how they compare to Earth. Temperatures given for TOI 270’s planets are equilibrium temperatures, calculated without the warming effects of any possible atmospheres. Image Credits: NASA’s Goddard Space Flight Center/Scott Wiessinger.

“This system is exactly what TESS was designed to find — small, temperate planets that pass, or transit, in front of an inactive host star, one lacking excessive stellar activity, such as flares,” said lead researcher Maximilian Günther, a Torres Postdoctoral Fellow at the Massachusetts Institute of Technology’s (MIT) Kavli Institute for Astrophysics and Space Research in Cambridge. “This star is quiet and very close to us, and therefore much brighter than the host stars of comparable systems. With extended follow-up observations, we’ll soon be able to determine the make-up of these worlds, establish if atmospheres are present and what gases they contain, and more.”

A paper describing the system was published in the journal Nature Astronomy and is now available online.

The innermost planet, TOI 270 b, is likely a rocky world about 25% larger than Earth. It orbits the star every 3.4 days at a distance about 13 times closer than Mercury orbits the Sun. Based on statistical studies of known exoplanets of similar size, the science team estimates TOI 270 b has a mass around 1.9 times greater than Earth’s.

Animation above: Compare and contrast worlds in the TOI 270 system with these illustrations of each planet. Temperatures given for TOI 270 planets are equilibrium temperatures, calculated without taking into account the warming effects of any possible atmospheres. Animation Credits: NASA’s Goddard Space Flight Center.

All of the planets are expected to be tidally locked to the star, which means they only rotate once every orbit and keep the same side facing the star at all times, just as the Moon does in its orbit around Earth.

Planet c and d might best be described as mini-Neptunes, a type of planet not seen in our own solar system. The researchers hope further exploration of TOI 270 may help explain how two of these mini-Neptunes formed alongside a nearly Earth-size world.

Transiting Exoplanet Survey Satellite or TESS. Image Credit: NASA

“An interesting aspect of this system is that its planets straddle a well-established gap in known planetary sizes,” said co-author Fran Pozuelos, a postdoctoral researcher at the University of Liège in Belgium. “It is uncommon for planets to have sizes between 1.5 and two times that of Earth for reasons likely related to the way planets form, but this is still a highly controversial topic. TOI 270 is an excellent laboratory for studying the margins of this gap and will help us better understand how planetary systems form and evolve.”

Günther’s team is particularly interested in the outermost planet, TOI 270 d. The team estimates the planet’s equilibrium temperature to be about 150 degrees Fahrenheit (66 degrees C). This makes it the most temperate world in the system — and as such, a rarity among known transiting planets.

«TOI 270 is perfectly situated in the sky for studying the atmospheres of its outer planets with NASA’s future James Webb Space Telescope,» said co-author Adina Feinstein, a doctoral student at the University of Chicago. «It will be observable by Webb for over half a year, which could allow for really interesting comparison studies between the atmospheres of TOI 270 c and d.»

(Click on the image for enlarge)

Image above: The TOI 270 system is so compact that the orbits of Jupiter and its moons in our own solar system offer the closest reasonable comparison, as illustrated here. Image Credits: NASA’s Goddard Space Flight Center.

The team hopes further research may reveal additional planets beyond the three now known. If planet d has a rocky core covered by a thick atmosphere, its surface would be too warm for the presence of liquid water, considered a key requirement for a potentially habitable world. But follow-up studies may discover additional rocky planets at slightly greater distances from the star, where cooler temperatures could allow liquid water to pool on their surfaces.  

TESS is a NASA Astrophysics Explorer mission led and operated by MIT in Cambridge, Massachusetts, and managed by NASA’s Goddard Space Flight Center. Additional partners include Northrop Grumman, based in Falls Church, Virginia; NASA’s Ames Research Center in California’s Silicon Valley; the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts; MIT’s Lincoln Laboratory; and the Space Telescope Science Institute in Baltimore. More than a dozen universities, research institutes and observatories worldwide are participants in the mission.

Related links:

Nature Astronomy: https://www.nature.com/articles/s41550-019-0845-5

TESS (Transiting Exoplanet Survey Satellite): http://www.nasa.gov/tess

Images (mentioned), Animation (mentioned), Text, Credits: NASA/Rob Garner/Goddard Space Flight Center, by Francis Reddy.

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Crew Unloads Dragon as Russian Cargo Ships Depart, Prep for Launch

ISS — Expedition 60 Mission patch.

July 29, 2019

A new U.S. space freighter is open for business today after delivering its payload to the International Space Station on Saturday. Meanwhile, a Russian resupply rocket is processing for another space delivery mission on Wednesday that will take less than three and a half hours after launch.

NASA Flight Engineer Nick Hague opened Dragon’s hatch early Sunday beginning a month of cargo operations. His fellow crewmates Christina Koch and Andrew Morgan are unloading critical research samples and stowing them inside the station’s science freezers and incubators for analysis.

Image above: Russia’s Progress 73 cargo craft stands at its launch pad at the Baikonur Cosmodrome in Kazakhstan counting down to a Wednesday liftoff. Image Credit: Roscosmos.

The new experiments will be exploring microgravity’s effect on a variety of biological and physical processes benefitting humans on Earth and in space. The crew will be researching 3-D bio-printing, silica manufacturing, botany and tissue regeneration and a host of other space phenomena.

Progress MS-12 ready for launch

Robotics controllers will remove the International Docking Adapter-3 (IDA-3), a new commercial crew ship docking port, from Dragon’s unpressurized trunk in mid-August. A pair of spacewalkers will install the IDA-3 on the Harmony module’s space-facing Pressurized Mating Adapter a few days later.

Russia’s Pirs Docking Compartment port opened up today at 6:44 a.m. EDT when the Progress 72 (72P) cargo craft undocked completing a four-month stay at the orbiting lab. It will re-enter the Earth’s atmosphere loaded with trash and discarded gear for a fiery, but safe disposal over the Pacific Ocean.

International Space Station (ISS). Animation Credit: NASA

The new Progress 73 cargo ship will replace 72P after it launches Wednesday at 8:10 a.m. from the Baikonur Cosmodrome in Kazakhstan. It will dock to Pirs that same morning at 11:35 a.m. after just two Earth orbits packed with more food, fuel and supplies for the crew.

Cosmonauts Alexey Ovchinin and Alexander Skvortsov are training today on the tele-robotically operated rendezvous unit (TORU) for Wednesday’s arrival of the 73P. The duo will be in the Zvezda service module at the controls of the TORU monitoring the 73P’s approach ready to take over manual docking operations in the unlikely event of an emergency.

Related links:

Expedition 60: https://www.nasa.gov/mission_pages/station/expeditions/expedition60/index.html

3-D bio-printing: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Facility.html?#id=7599

Silica manufacturing: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7716

Botany: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7892

Tissue regeneration: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=1676

International Docking Adapter-3 (IDA-3): https://www.nasa.gov/feature/meet-the-international-docking-adapter

Harmony module: https://www.nasa.gov/mission_pages/station/structure/elements/harmony

Pirs Docking Compartment: https://www.nasa.gov/mission_pages/station/structure/elements/pirs-docking-compartment

Zvezda service module: https://www.nasa.gov/mission_pages/station/structure/elements/zvezda-service-module.html

Space Station Research and Technology: https://www.nasa.gov/mission_pages/station/research/index.html

International Space Station (ISS): https://www.nasa.gov/mission_pages/station/main/index.html

Image (mentioned), Animation (mentioned), Text, Credits: NASA/Mark Garcia/ROSCOSMOS/SciNews.

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A Stellar Stream in the Milky Way Provides Evidence of Dark Substructure

For scientists and non-scientists alike, the discovery tells an exciting, edge-of-your-seat story. “We know that 90% of the mass in our universe is invisible. We don’t know what it is, but we’re curious,” said Dr. Ana Bonaca, ITC Fellow at the CfA and lead author of the study. “Stellar streams, which are what we’re studying here, tell us the story of our galaxy. They are so long and thin that they are sensitive to the tiniest disturbances as they orbit through the galaxy. Our findings are that…in action.”

Gaia, a mission of the European Space Agency (ESA), had a second data release in April 2018, which provided the basis for a new study of GD-1, the longest and most visible thin stellar stream in the Milky Way. Typically, stars are distributed close to uniformly along such streams, so scientists immediately noticed that some of the stars in the GD-1 stream were not behaving as expected.

“Stellar streams were thought to be more or less smooth in appearance, but GD-1 has gaps or regions of lower density along the stream. Close to one of these gaps there is an offshoot of misaligned stars,” said Adrian Price-Whelan, a coauthor of the study. “So first, we found something interesting that didn’t match what we expected to see, thanks to Gaia.”

Stellar streams are associations of stars that once previously belonged to a dwarf galaxy or a globular cluster, but that were pulled out by the Milky Way’s tidal forces and stretched out into streams. In the standard picture, these streams are long, thin, and regular. The observed behavior in GD-1, however, could not be explained by tidal forces alone. Instead, Bonaca and collaborators used numerical simulations to show that the observed gap and spur features could be the result of the stream encountering a dense, massive object.

“We considered a number of different objects as potential sources of perturbation, but none of them seemed to fit. We looked at the orbits of all known satellites in the Galaxy, but none crossed paths with GD-1 recently. We also considered whether molecular clouds could have done the damage because GD-1 crosses the Milky Way disk, but found they are not dense enough,” said Bonaca. “There is no obvious culprit.”

With no known culprits, scientists have turned to more exotic explanations, and that’s big news for dark matter theorists. “One of the fundamental predictions of the dark-matter model is that there ought to be many concentrations or clusters of dark matter orbiting in the outskirts of our Galaxy. This stream looks like it can be used to find those small clumps of dark matter,” said David Hogg, a coauthor of the study. “Ruling out all other possibilities and actually detecting a small clump of dark matter would be a huge clue for understanding the nature of this important component of the Universe.”

While Gaia data was used to make initial observations, the team has since conducted follow-up observations with Hectochelle—a multi-object echelle spectrograph—at the MMT Observatory, located at the Fred Lawrence Whipple Observatory at Mt. Hopkins in Arizona. These new data will help in locating the dark substructure. In addition, Bonaca and other scientists have begun observing other stellar streams with unusual features.

“When something passes close to a stellar stream, it leaves evidence behind, and we can see that something happened there. Even if it’s dark matter. Even if it’s invisible,” said Bonaca. “And if it is a clump of dark matter, there should be many of them. So we’re setting out to search for such oddities in other streams to find out for sure.”

The results of the study are published in the Astrophysical Journal. In addition to Bonaca, the team consisted of CfA scientist Charlie Conroy; David W. Hogg representing the Centers for Cosmology and Particle Physics and for Data Science at New York University, Max-Planck-Institut fur Astronomie, and Flatiron Institute; and Adrian M. Price-Whelan at Princeton University and the Flatiron Institute.

Headquartered in Cambridge, Mass., the Center for Astrophysics | Harvard & Smithsonian (CfA) is a collaboration between the Smithsonian Astrophysical Observatory and the Harvard College Observatory. CfA scientists, organized into six research divisions, study the origin, evolution and ultimate fate of the universe.

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Stanton Drew Prehistoric Stone Circles, Stanton Drew, Somerset, 25.7.19.

Stanton Drew Prehistoric Stone Circles, Stanton Drew, Somerset, 25.7.19.

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‘The Cove’ Stone Setting at Stanton Drew, Somerset, 25.7.19.

‘The Cove’ Stone Setting at Stanton Drew, Somerset, 25.7.19.

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Shape shifting protocells hint at the mechanics of early life

Inspired by the processes of cellular differentiation observed in developmental biology, an interdisciplinary team of researchers at the University of Bristol have demonstrated a new spontaneous approach to building communities of cell-like entities (protocells) using chemical gradients.

Shape shifting protocells hint at the mechanics of early life
Optical (top) and fluorescence (bottom) microscopy images of a protocell community showing four protocell types produced
spontaneously in an intersecting chemical gradient. Two different artificial morphogens are injected from the left and right
sides of the array along the x axis to generate an opposing gradient that translates into different changes in shape,
 composition and fluorescence in the protocells. Labels for the shape-shifting types are shown in the top row
[Credit: University of Bristol]

In a new study published in the journal Nature Communications, Professor Stephen Mann from Bristol’s School of Chemistry, together with colleagues Dr. Liangfei Tian, Dr. Mei Li, and Dr. Avinash Patil in the Bristol Centre for Protolife Research, and Professor Bruce Drinkwater from the Faculty of Engineering used a chemical gradient to transform a uniform population of small droplets into a diverse community of artificial cells.

The team first used ultrasonic waves to create regular rows of thousands of droplets containing the energy storage molecule ATP. They then allowed shape-shifting molecules (artificial morphogens) to diffuse in one direction through the population.

As the morphogens came into contact with the droplets, the droplets transformed row by row into membrane-bounded protocells with different shapes, chemical compositions and enzyme activities. How the droplets changed was dependent on the local morphogen concentration in the advancing chemical gradient.

Waves of differentiation were seen to travel across the population, leaving a pattern of differentiated protocells such that a complex and ordered community emerged spontaneously from the homogeneous population.

Professor Mann said: «This work opens up a new horizon in protocell research because it highlights the opportunities for spontaneously constructing protocell communities with graded structure and functionality.

«Although the research is just beginning, the results provide a step towards developing artificial cell platforms for chemical sensing and monitoring under non-equilibrium (flow-based) conditions.»

Dr. Tian added: «As droplet-based protocells have been proposed as plausible progenitors to membrane-bounded protocells on the early Earth, our work could have implications for contemporary theories of the origin of life.

«In particular, as chemical gradients produce protocell diversity from uniform populations, maybe a similar mechanism was responsible for the emergence of functional complexity in ancient proto-living systems.»

Source: University of Bristol [July 25, 2019]



Massive 500kg sauropod femur found in France

The thigh bone of a giant dinosaur has been found by paleontologists working at a site in the Charente in south west France.

Massive 500kg sauropod femur found in France
The bone was discovered earlier in the week during excavations at the palaeontological site
of Angeac-Charente near Châteauneuf-sur- Charente, southwestern France
[Credit: Georges Gobet/AFP]

The two-metre long femur, which weighs half a tonne, was found in 140 million-year-old former marshland now in the vineyards around Cognac.
The Angeac-Charente excavation site is unique in Europe and 7,500 bones belonging to 45 different dinosaur species have been found there since scientists first began excavating it in 2010.

Massive 500kg sauropod femur found in France
The femur weighs approximately 500 kilos
[Credit: Georges Gobet/AFP]

The thigh bone is thought to have belonged to a sauropod, a herbivorous dinosaur believed to be the largest animal that ever walked the earth.
Jean-François Tournepiche, curator at the Angouleme Museum, said: «This femur is huge! And in an exceptional state of conservation. It’s very moving.»

Massive 500kg sauropod femur found in France
The enormous bone probably belonged to a sauropod
[Credit: Georges Gobet/AFP]

Ronan Allain, paleontologist at the Natural History Museum in Paris, added: «We can see the insertions of muscles and tendons, scars.
«This is a very rare find as large pieces tend to collapse on themselves, to fragment.»

Massive 500kg sauropod femur found in France
A large pelvis bone was also uncovered at the site
[Credit: Georges Gobet/AFP]

Over the last decade, scientists have managed to reconstitute more than 50 percent of a sauropod using several individuals discovered at Angeac.

Source: The Local [July 25, 2019]



Pieces of Buddhist text discovered in Afghanistan’s Mes Aynak

Pieces of a Buddhist manuscript believed to date back to around the seventh century discovered at the ancient settlement Mes Aynak near Kabul suggest the site was a prosperous Buddhist city, an Afghan archaeological institute revealed.

Pieces of Buddhist text discovered in Afghanistan's Mes Aynak
Pieces of Buddhist scriptures found at the Mes Aynak ruins
in Afghanistan [Credit: Kyodo]

The sutras written in Sanskrit on tree bark were discovered on a hillside a few years ago in Mes Aynak, approximately 40 kilometers southeast of Kabul, by the Afghan Institute of Archaeology, which believes the manuscripts may have been housed in an archive.

Pieces of Buddhist text discovered in Afghanistan's Mes Aynak
Part of the manuscript found at the Mes Aynak ruins
 in Afghanistan [Credit: Kyodo]

In 2009, the Afghan government began a full-scale excavation of the settlement, which is believed to have been occupied between the third and seventh centuries, and has since unearthed pagodas, Buddha statues and murals.
Experts said the site may have been the city described by seventh-century Chinese monk Xuanzang in the Great Tang Records on the Western Regions, which recorded his journey to India. The institute said it will take a few dozen years before excavation is completed.

Pieces of Buddhist text discovered in Afghanistan's Mes Aynak
The ancient settlement of Mes Aynak is seen approximately 40 kilometers
southeast of Kabul [Credit: Kyodo]

However, a Chinese company’s purchase from the Afghan government in 2007 of 30-year mining rights for a large copper deposit near Mes Aynak has generated concern that excavation of the ancient settlement could be hampered.

Source: Kyodo News [July 26, 2019]




    Солнечное затмение 14 декабря 2020 года  — полное  солнечное затмение  142  сароса , которое лучше всего будет видно в юго-восточной час...