четверг, 27 июня 2019 г.

Will DART make its target asteroid go wobbly? Hera will see

ESA — Hera Mission logo.

27 June 2019

There are models and simulations, but nobody knows exactly what is going to happen after NASA’s DART impactor crashes into the smaller of the two Didymos asteroids at 6.6 km/s – humankind’s first full-scale deflection test for planetary defence.

DART impacting asteroid

It will take detailed telescope and radar observations from Earth to find out, complemented by a close-up survey to be performed by ESA’s Hera mission.

The collision itself takes place in late 2022. Meanwhile, PhD student Harrison Agrusa from the University of Maryland – as part of a larger team studying the dynamics of the Didymos system – is among the most qualified people to make an educated guess.

DART mission profile

Harrison has been simulating the interaction between the fridge-sized DART spacecraft and smaller 160-m diameter Didymos asteroid hundreds of times, run on his university’s powerful computing cluster.

His simulations recreate the 780-m diameter main Didymos asteroid and its orbiting ‘Didymoon’ as a collection of small spheres – like the rubble piles that researchers believe these bodies to resemble – then apply the equivalent force of the DART impact.

“The interesting thing, depending on where DART hits and how hard, is that we can see a pronounced wobble triggered as a result,” explains Harrison.

Simulating Didymos asteroids

“We’ve compared four different simulation codes to study this post-impact swinging back and forth and seen the same effect recur in all of them, even with conservative estimates of DART’s momentum transfer.”

In asteroid researcher terms this effect is known as ‘libration’ – the same term used for the wobble of the Moon as seen from Earth, which means that different parts of the lunar surface can be observed over time.

Modelling Didymoon’s post-impact libration

Like the Moon, the smaller ‘Didymoon’ is expected to be tidally locked to its parent at the present time, although it has not yet been confirmed with ground-based observations. Long-range measurements of distant lightcurves – gradual patterns of light shifting over time – or radar imagery do not give enough detail.

In the same way, any wobble imparted to the asteroid by DART’s collision will not be visible from Earth. It will take close-up observations after Hera’s arrival to be sure.

Harrison has shown that this induced libration is closely related to the momentum transfer efficiency – in other words, Hera’s measuring of the libration can be used to constrain the asteroid’s deflection. Such a measurement is crucial to developing a usable, repeatable planetary defence technique.

Harrison Agrusa

In addition, Harrison notes that the ability to measure any libration in the post-impact asteroid will also open up a valuable scientific opportunity: “The fundamental frequency of the libration will depend on the mass of the secondary, and how that mass is distributed throughout its interior – in the same way that the frequency of a pendulum’s swing depends on its mass.

“So measuring this effect will give researchers an important insight into the nature of Didymoon’s interior, constraining our models. However, it is essential to have a spacecraft on location to make such a measurement.”

Harrison is part of the DART Dynamics Working Group, led by his PhD adviser Prof. Derek Richardson, tasked with performing dynamic modelling of the Didymos system before and after DART’s impact.

Hera surveying Didymos

“As an undergraduate I interned at Lawrence Livermore National Laboratory in northern California, where I encountered some researchers working on planetary defence,” explains Harrison. “I never even knew this was a field until then, but after that I decided I wanted to get involved.”

This summer Harrison returns to LLNL, where he will take advantage of their supercomputer facilities to perform full-scale impact simulations, modelling the ejecta material thrown off of the asteroid by the DART impact.

Hera: ESA’s planetary defence mission

“Overall, it’s great timing for me,” says Harrison. “When the DART mission ends with its impact in 2022, then my PhD does too. We’ll get a first glimpse of the actual shape of Didymoon from DART and the LICIA CubeSat – provided by ASI, the Italian Space Agency – it will deploy before colliding. Then, within a few years Hera will be providing its data, so we can rigorously compare our models to reality.”

The Hera mission will be presented to ESA’s Space19+ meeting this November, where Europe’s space ministers will take a final decision on flying the mission.

Related links:

Space19+: http://blogs.esa.int/space19plus/

University of Maryland: https://www.umd.edu/

Harrison Agrusa homepage: https://hagrusa.github.io/research/

DART: http://dart.jhuapl.edu/

Lawrence Livermore National Laboratory: https://www.llnl.gov/

Hera: http://www.esa.int/Our_Activities/Space_Safety/Hera

University of Maryland Astronomy Department: http://www.astro.umd.edu/

World’s best telescopes target asteroids for ESA’s Hera mission: http://www.esa.int/Our_Activities/Space_Safety/Hera/World_s_best_telescopes_target_asteroids_for_ESA_s_Hera_mission

Images, Animation, Videos, Text, Credits: ESA/Science Office/NASA/University of Maryland/H. Agrusa/ScienceOffice.org.

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A chaos found only on Mars

ESA — Mars Express Mission patch.

27 June 2019

Plan view of Aurorae Chaos

The cracked, uneven, jumbled landscape seen in this image from ESA’s Mars Express forms an intriguing type of terrain that cannot be found on Earth: chaotic terrain.

The feature visible here, Aurorae Chaos, is located in the ancient and equatorial Margaritifer Terra region of Mars. The terrain here is heavily cratered, and shows signs of myriad fascinating features – many of which are thought to be linked to past water activity.

These images show the southern part of Aurorae Chaos in detail, highlighting various swathes of fractured rock, mismatched peaks, flat-topped mounds (mesas), scarps, jumbled cliffs, and eroded craters.

Aurorae Chaos in context

These characteristic features sweep across the surface, and connect to a number of small outflow channels that spread into this image from beyond the top of the frame in the main colour image. These channels form the eastern end of one of Mars’ most famous features – a giant valley system called Valles Marineris, which cuts deep into the surface and spans thousands of kilometres.

This canyon is colossal: about 10 times as long, 20 times as wide, and 4.5 times as deep as Arizona’s Grand Canyon here on Earth. The Grand Canyon was carved out by running water, and is thus an excellent example of fluvial erosion – although this kind of erosion is different to that which formed Aurorae Chaos. At its eastern end, the martian canyon runs into a large network of steep-sided depressions that sit roughly four kilometres below the surrounding plains and host numerous chaotic terrains.

Topographic view of Aurorae Chaos

These differences in height are well illustrated in the accompanying topographic, perspective, and 3D views of this region, while the position of Aurorae Chaos with respect to surrounding valleys and chaotic terrain can be seen in the contextual view.

The division between the chaotic terrain and plains can also be seen clearly in these images. The left (south) side of the image is notably smoother and more featureless than the jumbled right (north) side, and the two regions are split by a prominent line carving diagonally across the frame. The transition area around this scarp is especially broken and fractured; this is thought to be caused as the martian crust stretched and moved. 

Perspective view of Aurorae Chaos

The ancient chaotic terrain we see on Mars holds information about how water once permeated and interacted with the planetary surface, including how it was transported, stored, and released.

Chaotic terrain is thought to have formed as chunks of the martian surface collapsed in dramatic events triggered by the heating of material containing ice or water-bearing minerals – possibly due to climatic or volcanic heat sources, or an impact from an asteroid or comet. This released large amounts of water, causing the terrain above to subside. The water then drained away quickly, leaving behind the messy, broken patterns seen in regions such as Aurorae Chaos, which is thought to have formed some 3.5 billion years ago.

Aurorae Chaos in 3D

However, it is not just visual evidence that suggests that water had a large role to play here. The wider region of Margaritifer Terra has been found to contain various sulphates and ancient clay deposits, indicating the past presence of evaporative processes and water-related outflows; some clays are even thought to require standing water in order to form, suggesting that large pools of liquid water may once have existed in this region.

Mars Express in orbit around Mars

Over the past 15 years Mars Express has imaged various chaos terrains on Mars, including Iani Chaos and Ariadnes Colles, using its High Resolution Stereo Camera, and continues to study the martian surface from orbit today. Our ability to explore Mars will be aided by the arrival of the ESA-Roscosmos ExoMars rover, named Rosalind Franklin, and an accompanying surface science platform in 2021. Together with the ExoMars Trace Gas Orbiter, which entered Mars orbit in 2016, they will continue our quest to explore the secrets of the Red Planet from orbit and from the ground.

Related links:

Mars Express: http://www.esa.int/Our_Activities/Space_Science/Mars_Express

ESA-Roscosmos ExoMars rover: http://www.esa.int/Our_Activities/Human_and_Robotic_Exploration/Exploration/ExoMars/ExoMars_2020_rover

Trace Gas Orbiter (TGO): http://www.esa.int/Our_Activities/Human_and_Robotic_Exploration/Exploration/ExoMars/First_results_from_the_ExoMars_Trace_Gas_Orbiter

HRSC at DLR: http://www.dlr.de/dlr/en/desktopdefault.aspx/tabid-10364/548_read-400/#/gallery/657

HRSC data viewer: http://hrscview.fu-berlin.de/

Frequently asked questions: http://www.esa.int/Our_Activities/Space_Science/Mars_Express/Frequently_asked_questions

Images, Text, Credits: ESA/DLR/FU Berlin, CC BY-SA 3.0 IGO/NASA MGS MOLA Science Team.

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A Whirlpool ‘Warhol’ from NASA’s Spitzer Telescope

NASA — Spitzer Space Telescope patch.

June 27, 2019

Image above: This multipanel image show how different wavelengths of light can reveal different features of a cosmic object. On the left is a visible light image of the Whirlpool galaxy. The next image combines visible and infrared light, while the two on the right show different wavelengths of infrared light. Image Credits: NASA/JPL-Caltech.

Unlike Andy Warhol’s famous silkscreen grids of repeating images rendered in different colors, the varying hues of this galaxy represent how its appearance changes in different wavelengths of light — from visible light to the infrared light seen by NASA’s Spitzer Space Telescope.

The Whirlpool galaxy, also known as Messier 51 and NGC 5194/5195, is actually a pair of galaxies that are tugging and distorting each other through their mutual gravitational attraction. Located approximately 23 million light-years away, it resides in the constellation Canes Venatici.

The leftmost panel (a) shows the Whirlpool in visible light, much as our eye might see it through a powerful telescope. In fact, this image comes from the Kitt Peak National Observatory 2.1-meter (6.8-foot) telescope. The spiraling arms are laced with dark threads of dust that radiate little visible light and obscure stars positioned within or behind them.

The second panel from the left (b) includes two visible-light wavelengths (in blue and green) from Kitt Peak but adds Spitzer’s infrared data in red. This emphasizes how the dark dust veins that block our view in visible light begin to light up at these longer, infrared wavelengths.

Spitzer’s full infrared view can be seen in the right two panels, which cover slightly different ranges of infrared light.

In the middle-right panel (c), we see three wavelengths of infrared light: 3.6 microns (shown in blue), 4.5 microns (green) and 8 microns (red). The blended light from the billions of stars in the Whirlpool is brightest at the shorter infrared wavelengths and is seen here as a blue haze. The individual blue dots across the image are mostly nearby stars and a few distant galaxies. Red features show us dust composed mostly of carbon that is lit up by the stars in the galaxy.

This glowing dust helps astronomers see where the densest areas of gas pile up in the spaces between the stars. Dense gas clouds are difficult to see in visible or infrared light, but they will always be present where there is dust.

The far-right panel (d) expands our infrared view to include light at a wavelength of 24 microns (in red), which is particularly good for highlighting areas where the dust is especially hot. The bright reddish-white spots trace regions where new stars are forming and, in the process, heating their surroundings.

The infrared views of the Whirlpool galaxy also show how dramatically different its two component parts are: The smaller companion galaxy at the top of the image has been stripped nearly clean of dust features that stand out so brilliantly in the lower spiral galaxy. The faint bluish haze seen around the upper galaxy is likely the blended light from stars thrown out of the galaxies as these two objects pull at each other during their close approach.

Animation Credit: NASA

The Kitt Peak visible-light image (a) shows light at 0.4 and 0.7 microns (blue and red). The rightmost two images (c and d) are from Spitzer with red, green and blue corresponding to wavelengths of 3.6, 4.5 and 8.0 microns (middle right) and 3.6, 8.0 and 24 microns (far right). The middle-left (b) image blends visible wavelengths (blue/green) and infrared (yellow/red). All of the data shown here were released as part of the Spitzer Infrared Nearby Galaxies Survey (SINGS) project, captured during Spitzer’s cryogenic and warm missions: https://www.nasa.gov/mission_pages/spitzer/news/spitzer-20090506.html

The Jet Propulsion Laboratory in Pasadena, California, manages the Spitzer Space Telescope mission for NASA’s Science Mission Directorate in Washington. Science operations are conducted at the Spitzer Science Center at Caltech in Pasadena. Space operations are based at Lockheed Martin Space Systems in Littleton, Colorado. Data are archived at the Infrared Science Archive housed at IPAC at Caltech. Caltech manages JPL for NASA.

For more information on Spitzer, visit:

http://www.nasa.gov/spitzer and http://www.spitzer.caltech.edu/

Image (mentioned), Animation (mentioned), Text, Credits: NASA/JPL/Calla Cofield.

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‘Bathtub rings’ around Titan’s lakes might be made of alien crystals

The frigid lakeshores of Saturn’s moon Titan might be encrusted with strange, unearthly minerals, according to new research being presented here.

'Bathtub rings' around Titan's lakes might be made of alien crystals
Artistic depiction of a methane river delta on Titan
[Credit: Ron Miller]

Scientists re-creating Titan-esque conditions in their laboratory have discovered new compounds and minerals not found on Earth, including a co-crystal made of solid acetylene and butane.

Acetylene and butane exist on Earth as gases and are commonly used for welding and camp stove fuel. On Titan, with its extremely cold temperatures, acetylene and butane are solid and combine to form crystals, the new research found.

The new mineral might be responsible for the bathtub rings that are suspected to exist around Titan’s hydrocarbon lakes, according to Morgan Cable of NASA’s Jet Propulsion Laboratory at the California Institute of Technology, who will present the new research Monday at the 2019 Astrobiology Science Conference.

Titan’s lakes are filled with liquid hydrocarbons. Previous research using images and data gathered during the Cassini mission has shown that lakes in the moon’s dry regions near the equator contain signs of evaporated material left behind, like rings on a bathtub.

To create Titan-like conditions in the laboratory, the researchers started with a custom-built cryostat, an apparatus to keep things cold. They filled the cryostat with liquid nitrogen to bring the temperature down. They then warmed the chamber slightly, so the nitrogen turned to gas, which is mostly what Titan’s atmosphere contains. Next, they threw in what abounds on Titan, methane and ethane, as well as other carbon-containing molecules, and looked for what formed.

'Bathtub rings' around Titan's lakes might be made of alien crystals
A false-colour, near infrared view of Titan’s northern hemisphere collected by NASA’s Cassini spacecraft shows
 the moon’s seas and lakes. Orange areas near some of them may be deposits of organic evaporite minerals
 left behind by receding liquid hydrocarbon [Credit: NASA/JPL-Caltech/Space Science Institute]

The first things to drop out of their Titan hydrocarbon soup were benzene crystals. Benzene is perhaps best known as a component of gasoline and is a snowflake-shaped molecule made out of a hexagonal ring of carbon atoms. But Titan benzene held a surprise: The molecules rearranged themselves and allowed ethane molecules inside, creating a co-crystal.

The researchers then discovered the acetylene and butane co-crystal, which is probably a lot more common on Titan than benzene crystals, based on what’s known about the moon’s composition, Cable said.

In the moon’s cold climate, the acetylene-butane co-crystals might form rings around the moon’s lakes as the liquid hydrocarbons evaporate and the minerals drop out — in the same way that salts can form crusts on the shores of Earth’s lakes and seas, according to Cable.

To confirm whether Titan has bathtub rings of co-crystals and other, undiscovered, hydrocarbon crystals, scientists will have to wait until a spacecraft can visit the shorelines of this moon, Cable said.

«We don’t know yet if we have these bathtub rings,» Cable said. «It’s hard to see through Titan’s hazy atmosphere.»

Source: American Geophysical Union [June 24, 2019]



Roads and deforestation explode in the Congo basin

Logging roads are expanding dramatically in the Congo Basin, leading to catastrophic collapses in animal populations living in the world’s second-largest rainforest, according to research co-led by a scientist at James Cook University in Australia.

Roads and deforestation explode in the Congo basin
Road development for logging in the Congo Basin
[Credit: William Laurance]

Just as worrying is that the rate of forest destruction caused by new roads in the Congo Basin has risen sharply over time, quadrupling since 2000.

«The situation in the Congo Basin is scary on top of more scariness,» said Professor Bill Laurance, who has worked in Africa for 15 years. «New roads are opening a Pandora’s box of activities such as illegal deforestation, mining, poaching and land speculation.»

Laurance helped lead an international team that exhaustively mapped all roads in the Congo region, using satellite imagery. They found that since 2003, the total length of roads has increased by nearly 100,000 kilometres—from 144,000 to 231,000 kilometres overall.

«Industrial logging is a key economic driver for much of the road building,» said Laurance. «Some logging roads are abandoned, but many are used by slash-and-burn farmers and poachers to penetrate deep into surviving rainforests.»

«As a result, the global population of forest elephants has collapsed by two-thirds over the past decade,» said Laurance. «Elephants, gorillas and chimps hardly have anywhere to hide from poachers now.»

Laurance and his team are especially worried about the vast Democratic Republic of Congo, or DRC, the largest nation in the Congo Basin.

«When you build a new road, you get 2-3 times more deforestation in the DRC than anywhere else in the Congo Basin,» said Laurance.

«That’s super-worrying because the DRC has plans to sharply increase logging. Last year, it leased a massive 650,000 hectares (1.6 million acres) of pristine rainforest to aggressive Chinese logging companies,» said Laurance. «And that’s just the tip of the iceberg.»

However, not all the study’s findings were negative. One promising result is that, outside of the DRC, many roads inside logging areas are being abandoned and the forest allowed to regenerate after the timber is harvested.

«This suggests that there’s considerable scope to make industrial logging less damaging to forests,» said Laurance. «An especially promising strategy is for logging companies to block roads or destroy bridges over creeks after they’ve harvested the timber.»

«Of course, we’d greatly prefer to have pristine forests. But African nations must earn money from their forests, and if better managed, selective logging could provide income and be a lot less destructive.»

Overall, a key conclusion of the study is that much road building in Africa is extremely harmful, destroying and fragmenting forests and destroying wildlife populations.

«Corruption and a massive influx of aggressive foreign developers is the biggest worry, along with rapid population growth,» said Laurance. «It all leads to destructive development and road building.»

«China in particular has the most predatory practices for logging, mining and road building in Africa,» said Laurance. «Many Africans are starting to see this, and I just hope something can be done in time.»

The research is published in Nature Sustainability.

Source: James Cook University [June 24, 2019]



Zimbabwe wants ivory ban lifted so it can sell $600-mln stockpile

Zimbabwe President Emmerson Mnangagwa opened a UN wildlife summit on Monday with a call to lift the global ivory trade ban so that the country can sell $600 million of stockpiled tusks.

Zimbabwe wants ivory ban lifted so it can sell $600-mln stockpile
Some countries in southern Africa are pushing for a global ivory ban
to be relaxed as their elephant numbers grow [Credit: AFP]

Mnangagwa said selling the elephant tusks and rhino horns would enable the impoverished nation to fund conservation efforts for 20 years.

Zimbabwe, Botswana, Namibia and Zambia have all cited the growing number of elephants in some areas in their bid to have the ban relaxed, angering many conservationists.

Opening the UNEP wildlife economy summit in Victoria Falls, Mnangagwa called «for the free trade in hunting products as these can have an important impact on national and local economies.»

«Currently Zimbabwe has about $600 million dollars worth of ivory and rhino horns stocked—most of which is from natural attrition of those animals. The revenue would suffice to finance our operational conservation efforts for the next two decades.»

The Convention on International Trade in Endangered Species (CITES), which prohibits the sale of ivory, is under pressure from southern African countries that have seen growing elephant numbers.

But over the past decade, the population of elephants across Africa has fallen by about 111,000 to 415,000, largely due to poaching, according to the International Union for Conservation of Nature (IUCN).

Botswana recently sparked controversy by lifting its ban on hunting, saying the move would help control a booming elephant population that was damaging farmers’ livelihoods.

Source: AFP [June 24, 2019]



Ancient intervention could boost dwindling water reserves in coastal Peru

Nestled between the Pacific Ocean and the Andes mountains, Peru’s coastal region relies on surface water from the Andes for drinking water, industry, and animal and crop farming.

Ancient intervention could boost dwindling water reserves in coastal Peru
Ancient water canals wind through the Andean mountains. Lima is downstream
[Credit: Sam Grainger, Imperial College London]

The region, which includes Peru’s capital city Lima, is often overwhelmed with rain in the wet season — but by the time the dry season comes, water is scarce.

These factors, together with Lima’s rapidly growing population, mean the city struggles to supply water to its 12 million residents during the dry months of May to October.

Now, Imperial researchers and their colleagues at the Regional Initiative for Hydrological Monitoring of Andean Ecosystems in South America, have outlined how reviving ancient water systems could help save wet season water for the dry season, where it is desperately needed.

To do so, they studied a water system in Huamantanga, Peru — one of the last of its kind.

Ancient intervention could boost dwindling water reserves in coastal Peru
Animation showing monthly rainfall in the tropical Andes. Several synoptic scale processes influence where
and when water is distributed in the region. Humid and warm air transports water vapour from the Amazon
and is blocked by the Andean mountain barrier producing extreme differences between the eastern and
 the western slopes in the Andes. The subtropical anticyclone in the Pacific and the cold marine
Humboldt current maintain stable arid conditions along the coast of Peru and northern Chile
[Credit: Boris Ochoa-Tocachi, Imperial College London, 2019]

Coastal Peru’s continuously stressed systems struggle to cope with increasing demand and are fragile — a landslide, for example, could easily cut off Lima’s water supply.

Senior author Dr Wouter Buytaert, of Imperial’s Department of Civil and Environmental Engineering, said: «The people of Lima live with one of the world’s most unstable water situations. There’s too much water in the wet seasons, and too little in the dry ones.

«The indigenous peoples of Peru knew how to get around this, so we’re looking to them for answers.»

Ancient Peruvian civilisations in 600 AD created systems within mountains to divert excess rainwater from source streams onto mountain slopes and through rocks.

The water would take some months to trickle through the system and resurface downstream — just in time for the dry season.

Ancient intervention could boost dwindling water reserves in coastal Peru
Diversion canals guide water through the Andean landscape
[Credit: Musuq Briceno, CONDESAN]

To study this, the researchers looked at one such system in Huamantanga. They used dye tracers and hydrological monitoring to study the system from the wet to dry seasons of 2014-2015 and 2015-2016. Social scientists involved also worked with Huamantanga’s local people to understand the practice and help map the landscape.

They found the water took between two weeks and eight months to re-emerge, with an average time of 45 days. From these time scales, they calculated that, if governments upscale the systems to cater to today’s population size, they could reroute and delay 35 per cent of wet season water, equivalent to 99 million cubic metres per year of water through Lima’s natural terrain.

This could increase the water available in the dry season by up to 33 per cent in the early months, and an average of 7.5 per cent for the remaining months. The method could essentially extend the wet season, providing more drinking water and longer crop-growing periods for local farmers.

The study, published in Nature Sustainability, is the first to examine the pre-Inca system in this much detail to find answers to modern problems. The authors say their research shows how indigenous systems could complement modern engineering solutions for water security in coastal Peru.

Ancient intervention could boost dwindling water reserves in coastal Peru
Water pond in the dry season [Credit: Sam Grainger, Imperial College London]

Lead author Dr Boris Ochoa-Tocachi, also from Imperial’s Department of Civil and Environmental Engineering, said: «With the advent of modern science, you’d be forgiven for wondering how ancient methods could apply to modern day problems. However, it turns out that we have lots to learn from our ancestors’ creative problem-solving skills.»

Dr Buytaert said: «Like many tropical cities, Lima’s population is growing fast — too fast for water reserves to keep up during dry seasons.

«Upscaling existing pre-Inca systems could help relieve Peru’s wet months of water and quench its dry ones.»

The seasonal variability typical of coastal Peru is worsened by human impacts — particularly by melting glaciers caused by global warming. Humans also contribute to soil erosion, which renders soil too weak to support dams big enough to hold all the water.

Ancient intervention could boost dwindling water reserves in coastal Peru
Water pond in the wet season [Credit: Junior Gil-Rios, CONDESAN]

Climate change also makes wet seasons wetter, and dry seasons drier — making the need for effective water storage in Peru even more urgent.

In addition, the uncertainty of our climate’s future makes it difficult to design and build systems that are intended to last for decades into the future.

The authors say combining pre-Inca systems with classic structures, such as smaller dams, could spread the workload across methods and increase adaptability in an unpredictable climate.

Dr Buytaert explained: «Because we can’t rely fully on one method, we must be open-minded and creative — but our study shows we have lots to learn from the way Peru’s indigenous population intelligently managed their landscape 1,400 years ago.»

Ancient intervention could boost dwindling water reserves in coastal Peru
Conceptual representation of how the pre-Inca infiltration system works. Water is diverted during the wet season using
 canals that transport surplus water during the wet season to high permeabilityzones. Water penetrates the soil
and emerges in downstream springs after weeks or even months, which provides water during the dry season
[Credit: Ochoa-Tocachi et al. 2019]

The researchers looked only at one system, so the results of similar work will likely differ throughout Peru’s coastal areas. However, they say their work presents a strong argument for using nature-based solutions to improve water security, which currently tops water agendas both locally and globally.

They continue to study the area to learn more about how indigenous knowledge, practices, and systems can help supply water to large urban populations in water-unstable, dry environments. In doing so, they hope to improve coastal Peru’s water security and resilience to a changing and unpredictable climate.

Dr Ochoa-Tocachi concluded: «This is a fascinating example of ingenuity within local communities and shows the enormous potential of indigenous knowledge to complement modern science.

«Beyond this fascinating example of ingenious problem-solving, our research shows the enormous potential for indigenous knowledge and rural science to complement modern science».

Author: Caroline Brogan | Source: Imperial College London [June 24, 2019]



Hue times two: A second look at the colour of dinosaur eggs

After garnering worldwide attention last year for her research on the origins of egg colour in birds, Yale paleontologist Jasmina Wiemann has taken a second look at her eggshells.

Hue times two: A second look at the color of dinosaur eggs
From front to back: an emu egg, a eumaniraptoran theropod egg, and a crocodile egg
[Credit: Jasmina Wiemann]

Wiemann had found that all colours and spots on modern birds’ eggs derived from a single evolutionary source among dinosaurs. Part of the finding came from an analysis of pigments found in 18 fossil dinosaur eggshell samples from around the world. Wiemann’s team tested for the presence of two eggshell pigments and found them in eggshells belonging to Eumaniraptoran dinosaurs, which include small, carnivorous dinosaurs such as Velociraptor.

But a lingering question within the scientific community had to do with whether pigments found in the shells of dinosaur eggs actually meant the eggs looked different to the naked eye. A certain level of pigment may have existed in the chemical make-up of the shells without manifesting in the outward colour of the eggs, some observers noted.

A new, follow-up study published this week in the journal Nature indicates that Wiemann’s initial conclusion was correct.

«We demonstrate that our analytical approach actually targets egg colour and not only egg pigmentation, as we need substantial concentrations of the red pigment, protoporphyrin, to elicit a positive signal for egg colour,» Wiemann said. «The result is the same. Egg colour had a single evolutionary origin in eumaniraptorans.»

A previous study by a different research team had analyzed pigmentation in the eggshells of Siamese crocodiles. That study speculated that pigmentation, but not egg colour, may have originated with archosaurs (a group that includes dinosaurs, birds, and crocodiles).

«We had the opportunity to directly address their question and test—thanks to the Yale Peabody Museum of Natural History’s egg collection—if there is, indeed, evidence for the red pigment in Siamese crocodile eggshells,» Wiemann said. «We showed that there are no detectable quantities of protoporphyrin in the eggshells of Siamese crocodiles.»

Author: Jim Shelton | Source: Yale University [June 24, 2019]



Study shows how icy outer solar system satellites may have formed

Using sophisticated computer simulations and observations, a team led by researchers from the Earth-Life Science Institute (ELSI) at Tokyo Institute of Technology has shown how the so-called trans-Neptunian Objects (or TNOs) may have formed. TNOs, which include the dwarf planet Pluto, are a group of icy and rocky small bodies—smaller than planets but larger than comets—that orbit the Solar System beyond the planet Neptune. TNOs likely formed at the same time as the Solar System, and understanding their origin could provide important clues as to how the entire Solar System originated.

Study shows how icy outer solar system satellites may have formed
The masses of the satellite(s) range from 1/10 to 1/1000 of the corresponding TNOs. For comparison,
Earth and Moon are also shown [Credit: NASA/APL/SwRI/ESA/STScI]

Like many solar system bodies, including the Earth, TNOs often have their own satellites, which likely formed early on from collisions among the building blocks of the Solar System. Understanding the origin of TNOs along with their satellites may help understand the origin and early evolution of the entire Solar System. The properties of TNOs and their satellites—for example, their orbital properties, composition and rotation rates—provide a number of clues for understanding their formation. These properties may reflect their formation and collisional history, which in turn may be related to how the orbits of the giant planets Jupiter, Saturn, Neptune, and Uranus changed over time since the Solar System formed.
The New Horizons spacecraft flew by Pluto, the most famous TNO, in 2015. Since then, Pluto and its satellite Charon have attracted a lot of attention from planetary scientists, and many new small satellites around other large TNOs have been found. In fact, all known TNOs larger than 1000 km in diameter are now known to have satellite systems. Interestingly, the range of estimated mass ratio of these satellites to their host systems ranges from 1/10 to 1/1000, encompassing the Moon-to-Earth mass ratio (~1/80). This may be significant because Earth’s Moon and Charon are thought to have formed from a giant impactor.

Study shows how icy outer solar system satellites may have formed
Top panels show snapshots for the satellite-forming giant impact with about 1 km/s of the impact velocity and 75 degree
of the impact angle. Bottom panel shows the schematic view for the circularization of the satellite’s orbit due
to tidal interaction after satellite formation [Credit: Arakawa et al. 2019]

To study the formation and evolution of TNO satellite systems, the research team performed more than 400 giant impact simulations and tidal evolution calculations. «This is really hard work,» says the study’s senior author, Professor Hidenori Genda from the Earth-Life Science Institute (ELSI) at Tokyo Institute of Technology. Other Tokyo Tech team members included Sota Arakawa and Ryuki Hyodo.
The Tokyo Tech study found that the size and orbit of the satellite systems of large TNOs are best explained if they formed from impacts of molten progenitors. They also found that TNOs which are big enough can retain internal heat and remain molten for a span of only a few million years; especially if their internal heat source is short-lived radioactive isotopes such as Aluminum-26, which has also been implicated in the internal heating of the parent bodies of meteorites. Since these progenitors would need to have a high short-lived radionuclide content in order to be molten, these results suggest that TNO-satellite systems formed before the outward migration of the outer planets, including Neptune, or in the first ~ 700 million years of Solar System history.

Study shows how icy outer solar system satellites may have formed
The relationship between the initial eccentricity of the formed satellites and the final eccentricity after 4.5-billion-year
tidal evolution are shown for three cases. When planetary bodies are rigid for the whole time (right figure) or they
behave as a fluid for the first 1000 years (middle figure), most of the eccentricities were not damped, which
is not inconsistent with the observation. When they behave as a fluid for the first > 1 million years,
the resultant eccentricities are consistent with the observation [Credit: Arakawa et al. 2019]

Previous planet formation theories had suggested the growth of TNOs took much longer than the lifetime of short-lived radionuclides, and thus TNOs must not have been molten when they formed. These scientists found, however, that rapid TNO formation is consistent with recent planet formation studies which suggest TNOs formed via accretion of small solids to pre-existing bodies. The rapid formation of large TNOs is consistent with recent planet formation studies; however, other analyses suggest comets formed well after most short-lived radionuclides had decayed. Thus the authors note that there is still much work to be done to produce a unified model for the origin of the Solar System’s planetary bodies.

The findings are published in Nature Astronomy.

Source: Tokyo Institute of Technology [June 25, 2019]



2019 June 27 The Longer Days Image Credit & Copyright: …

2019 June 27

The Longer Days
Image Credit & Copyright: Gianluca Belgrado

Explanation: This persistent six month long exposure compresses the time from solstice to solstice (December 21, 2018 to June 16, 2019) into a single point of view. Dubbed a solargraph, the unconventional picture was recorded with a tall, tube-shaped pinhole camera using a piece of photographic paper. Fixed to a single spot at Casarano, Italy for the entire exposure, the simple camera continuously records the Sun’s daily path as a glowing trail burned into the photosensitive paper. Breaks and gaps in the trails are caused by cloud cover. At the end of the exposure, the paper was scanned to create the digital image. Of course, starting in December the Sun trails peak lower in the sky, near the northern hemisphere’s winter solstice. The trails trails climb higher as the days grow longer and the June 21st summer solstice approaches.

∞ Source: apod.nasa.gov/apod/ap190627.html

Cyanide compounds discovered in meteorites may hold clues to the origin of life

Cyanide and carbon monoxide are both deadly poisons to humans, but compounds containing iron, cyanide, and carbon monoxide discovered in carbon-rich meteorites by a team of scientists at Boise State University and NASA may have helped power life on early Earth. The extraterrestrial compounds found in meteorites resemble the active site of hydrogenases, which are enzymes that provide energy to bacteria and archaea by breaking down hydrogen gas (H2). Their results suggest that these compounds were also present on early Earth, before life began, during a period of time when Earth was constantly bombarded by meteorites and the atmosphere was likely more hydrogen-rich.

Cyanide compounds discovered in meteorites may hold clues to the origin of life
Artist’s concept of meteors impacting ancient Earth. Some scientists think such impacts
may have delivered water and other molecules useful to emerging life on Earth
[Credit: NASA’s Goddard Space Flight Center Conceptual Image Lab]

«When most people think of cyanide, they think of spy movies — a guy swallowing a pill, foaming at the mouth and dying, but cyanide was probably an essential compound for building molecules necessary for life,» explained Dr. Karen Smith, senior research scientist at Boise State University, Boise, Idaho. Cyanide, a carbon atom bound to a nitrogen atom, is thought to be crucial for the origin of life, as it is involved in the non-biological synthesis of organic compounds like amino acids and nucleobases, which are the building blocks of proteins and nucleic acids used by all known forms of life.
Smith is lead author of a paper on this research published in Nature Communications. Smith, along with Boise State assistant professor Mike Callahan, a co-author on the paper, developed new analytical methods to extract and measure ancient traces of cyanide in meteorites. They found that the meteorites containing cyanide belong to a group of carbon-rich meteorites called CM chondrites. Other types of meteorites tested, including a Martian meteorite, contained no cyanide.

«Data collected by NASA’s OSIRIS-REx spacecraft of asteroid Bennu indicate that it is related to CM chondrites,» said co-author Jason Dworkin of NASA’s Goddard Space Flight Center in Greenbelt, Maryland. «OSIRIS-REx will deliver a sample from Bennu to study on Earth in 2023. We will search for these very compounds to try to connect Bennu to known meteorites and to understand the potential delivery of prebiotic compounds such as cyanide, which may have helped start life on the early Earth or other bodies in the solar system.»

Cyanide compounds discovered in meteorites may hold clues to the origin of life
Meteorites contain metal-organic compounds that resemble portions of enzymes found in bacteria and archaea.
CN is cyanide, CO is carbon monoxide, Fe is iron, Ni is nickel [Credit: Smith et al. 2019]

Cyanide has been found in meteorites before. However, in the new work, Smith and Callahan were surprised to discover that cyanide, along with carbon monoxide (CO), were binding with iron to form stable compounds in the meteorites. They identified two different iron cyano-carbonyl complexes in the meteorites using high-resolution liquid chromatography-mass spectrometry. «One of the most interesting observations from our study is that these iron cyano-carbonyl complexes resemble portions of the active sites of hydrogenases, which have a very distinct structure,» Callahan said.

Hydrogenases are present in almost all modern bacteria and archaea and are widely believed to be ancient in origin. Hydrogenases are large proteins, but the active site — the region where chemical reactions take place — happens to be a much smaller metal-organic compound contained within the protein, according to Callahan. It is this compound that resembles the cyanide-bearing compounds the team discovered in meteorites.

An enduring mystery regarding the origin of life is how biology could have arisen from non-biological chemical processes. The similarities between the active sites in hydrogenase enzymes and the cyanide compounds the team found in meteorites suggests that non-biological processes in the parent asteroids of meteorites and on ancient Earth could have made molecules useful to emerging life.

«Cyanide and carbon monoxide attached to a metal are unusual and rare in enzymes. Hydrogenases are the exception. When you compare the structure of these iron cyano-carbonyl complexes in meteorites to these active sites in hydrogenases, it makes you wonder if there was a link between the two,» Smith added. «It’s possible that iron cyano-carbonyl complexes may have been a precursor to these active sites and later incorporated into proteins billions of years ago. These complexes probably acted as sources of cyanide on early Earth as well.»

Authors: Bill Steigerwald & Nancy Jones | Source: NASA/Goddard Space Flight Center [June 25, 2019]



Blue colour tones in fossilized prehistoric feathers

Examining fossilised pigments, scientists from the University of Bristol have uncovered new insights into blue colour tones in prehistoric birds.

Blue colour tones in fossilized prehistoric feathers
Eocoracias brachyptera fossil sample used for this study. The rich black texture on the surface is fossilized plumage
of the bird. Fossil is stored at Senckenberg Research Institute [Credit: Sven Traenkner, photographer
at the Senckenberg Research Institute and Nature Museum in Frankfurt]

For some time, paleontologists have known that melanin pigment can preserve in fossils and have been able to reconstruct fossil colour patterns.

Melanin pigment gives black, reddish brown and grey colours to birds and is involved in creating bright iridescent sheens in bird feathers.

This can be observed by studying the melanin packages called melanosomes, which are shaped like little cylindrical objects less than one-thousandth of a millimetre and vary in shape from sausage shapes to little meatballs.

However, besides iridescent colours, which is structural, birds also make non-iridescent structural colours. Those are, for example, blue colour tones in parrots and kingfishers. Until now, it was not known if such colours could be discovered in fossils.

This blue structural colour is created by the dense arrangement of cavities inside feathers, which scatters the blue light. Underneath is a layer of melanin that absorbs unscattered light.

Blue colour tones in fossilized prehistoric feathers
Reconstruction of Eocoracias brachyptera with hypothesized plumage coloration
[Credit: Marta Zaher/University of Bristol]

Paleontologists have shown that the feather itself, which is made of keratin, does not fossilise while the melanin does. Therefore, if a blue feather fossilised, the dark pigment may be the only surviving feature and the feather may be interpreted as black or brown.

Now researchers from the University of Bristol, led by Frane Barbarovic who is currently at the University of Sheffield, have shown that blue feather melanosomes are highly distinct from melanosomes that are from feathers expressing black, reddish-brown, brown and iridescent, but overlap significantly with some grey feather melanosomes.

By looking at plumage colourations of modern representatives of fossil specimen and reconstructing which colour was the most likely present in the fossil specimen, they were able to discriminate between melanosomes significant for grey and blue colour, leading to the reconstruction of prehistoric Eocoracias brachyptera as a predominantly blue bird.

Frane Barbarovic said: «We have discovered that melanosomes in blue feathers have a distinct range in size from most of colour categories and we can, therefore, constrain which fossils may have been blue originally.

«The overlap with grey colour may suggest some common mechanism in how melanosomes are involved in making grey colouration and how these structural blue colours are formed.

Blue colour tones in fossilized prehistoric feathers
Credit: Marta Zaher/University of Bristol

«Based on these results in our publication we have also hypothesized potential evolutionary transition between blue and grey colour.»

The research team now need to understand which birds are more likely to be blue based on their ecologies and modes of life. The blue colour is common in nature, but the ecology of this colour and its function in the life of birds is still elusive.

Frane Barbarovic added: «We also need to understand how grey colour is made. This is made in a very different way in birds than it is in mammals. We believe it is related to how the melanosome shape can result in a kind of self-assembling process in the feather and the surface tension of the melanosomes pull them into certain configurations inside a feather as it forms.»

The findings are published in the Journal of the Royal Society Interface.

Source: University of Bristol [June 25, 2019]



Piecing together the ancient croc that preyed on dinosaurs

A new species of crocodile has been described from opalised fossils found at Lightning Ridge in NSW, Australia, from a fossil unearthed more than a century ago, and a second one found more than 70 years later.

Piecing together the ancient croc that preyed on dinosaurs
Artist’s reconstruction of Isisfordia molnari [Credit: Jose Vitor Silva]

Dating back 100 million years, the new species, Isisfordia molnari, is one of the oldest known direct ancestors of today’s living crocodiles. The species was named after Ralph Molnar, a palaeontologist whose many valuable contributions to Australian science include research on fossil crocodiles. This is the second species of Isisfordia discovered, with Isisfordia duncani named in 2006 from fossils found near the Queensland outback town of Isisford.
Isisfordia molnari grew to between 1.5 and 2 metres in length, and is thought to have been a semi-aquatic ambush predator, like modern crocodiles. Its prey probably included small dinosaurs such as Weewarrasaurus.

Piecing together the ancient croc that preyed on dinosaurs
Photos of the partial braincase (top view) and jawbone of the new crocodile species, Isisfordia molnari,
from Lightning Ridge, NSW. (Not to scale) [Credit: Lachlan Hart]

Lead researcher Lachlan Hart, a Master of Science student at the University of New England in Armidale, explained how the new species was discovered: «The first crocodile fossil from Lightning Ridge, a partial jaw bone with teeth, was discovered in 1917, at a time when little was known about fossil crocodiles from the Australia’s age of dinosaurs. It found its way to the Australian Museum and was given a name that turned out to be incorrect.
«Then, in the early 2000s, opal buyers Peter and Lisa Carroll found a piece of fossil crocodile braincase (the rear section of the skull) from Lightning Ridge, and sold it to the Australian Museum; but still, there were so few Australian crocodile fossils known of this age that scientists also found this new piece difficult to interpret. After Isisfordia duncani was discovered in Queensland in 2006, it allowed us to make more sense of the earlier Lightning Ridge discoveries. Although they were similar, we found several differences that set the Lightning Ridge species apart.»

Piecing together the ancient croc that preyed on dinosaurs
Diagram of a crocodile skull, shown from above, highlighting the location of the fossils known for Isisfordia molnari.
Based on the skull of Isisfordia duncani [Credit: University of New England]

Piecing together the ancient croc that preyed on dinosaurs
Diagram of a crocodile skull, shown from underneath, highlighting the location of the fossils known for Isisfordia molnari.
Based on the skull of Isisfordia duncani [Credit: University of New England]

Like other fossils from Lightning Ridge, the Isisfordia molnari fossils are opalised, meaning that the original bone and tooth material has been replaced by opal. Other famous opalised fossils from Lightning Ridge include those of the recently announced herbivorous dinosaurs Fostoria dhimbangunmal and Weewarrasaurus pobeni, fossils of which are at the Australian Opal Centre, a public museum that earlier in 2019 secured $20 million to construct a new building at Lightning Ridge for its world-leading collections and programs.
«Lightning Ridge is one of the most important fossil sites in Australia,» said Australian Opal Centre palaeontologist and Special Projects Officer Jenni Brammall. «This new research is adding to a complex and intriguing picture not only of the dinosaurs of the time, but the animals and plants they lived with and the ecosystems they were part of.»

The new crocodile species was published this week in the journal PeerJ, by scientists from the University of New England, Australian Opal Centre and University of Queensland.

Source: University of New England [June 26, 2019]



Tooth enamel analyses offer insights into the diet and habitat of T. rex relative...

Together with an international team, Senckenberg scientist Herve Bocherens studied the fossilized teeth of the carnivorous dinosaur Tarbosaurus bataar. Based on stable isotopes, the researchers were able to draw inferences regarding the habitat and feeding habits of this relative of T. rex, who lived around 70 million years ago. According to the results, the carnivores were not very picky in their prey selection.

Tooth enamel analyses offer insights into the diet and habitat of T. rex relative tarbosaurus
Fragment of Tarbosaurus lower jaw with teeth sampled (white stripes on tooth enamel)
[Credit: Senckenberg]

The Gobi Desert in southern Mongolia is a well-known discovery site of fossil dinosaurs. “These fossils from the Cretaceous also include Tarbosaurus bataar, a representative of the Tyrannosaurids and relative of the famous Tyrannosaurus rex,” explains Prof. Dr. Herve Bocherens of the Senckenberg Centre for Human Evolution and Palaeoenvironment at the University of Tubingen.
Bocherens and his team of scientists examined the fossilized teeth of this up to twelve-meter-long dinosaur, using oxygen and carbon isotopes in the tooth enamel to draw inferences regarding the dinosaurs’ feeding habits and the environmental conditions at the time.

“It is amazing how much information is revealed by this approximately 70-million-year-old tooth enamel,” explains a delighted Bocherens, and he continues, “Our analyses show that the environment of these carnivorous reptiles was about 10 degrees Centigrade warmer than today and the amount of precipitation was subject to strong seasonal fluctuations. We assume that the dinosaurs inhabited closed forests – in a climate characterized by monsoons with cold, dry winters and hot, rainy summers.”

In addition, the researchers were able to reconstruct the Tarbosaurs’ diet based on the teeth from five differently aged individuals. According to the results, the carnivores were not very picky in their prey selection: their menu included both the Hadrosauridae, commonly known as “duck-billed dinosaurs,” as well as different species of vegetarian sauropods. “Our isotope studies therefore confirm the fossil discoveries and show that Tarbosaurus took up a position at the top of the food pyramid,” adds Bocherens in summary.

The study is published recently in the scientific journal Palaeogeography, Palaeoclimatology, Palaeoecology.

Source: Senckenberg Research Institute and Natural History Museum [June 26, 2019]




https://t.co/hvL60wwELQ — XissUFOtoday Space (@xufospace) August 3, 2021 Жаждущий ежик наслаждается пресной водой после нескольких дней в о...