среда, 20 ноября 2019 г.

Using AI to predict Earth’s future

ESA - European Space Agency logo.

Nov. 19, 2019

A recent ‘deep learning’ algorithm – despite having no innate knowledge of solar physics – could provide more accurate predictions of how the Sun affects our planet than current models based on scientific understanding.

Fresh from Earth

For decades, people have tried to predict the impact of the Sun on our planet’s atmosphere. Up until now, algorithms based on solar physics have been used to predict the shifting density of Earth’s atmosphere.

But with so many variables affecting the complex and dynamic layers of gases around Earth, Artificial Intelligence (AI) could provide real improvements in this area because of its ability to handle vastly more complex data, with important implications for how we fly missions in Earth orbit.

The Sun’s a real drag

The conditions in space vary depending on the mood swings of the Sun, known as ‘space weather’. The Sun spews out radiation in a constant stream, but it sometimes also sends out violent bursts of high energy particles that can directly hit our planet. These particles cause geomagnetic storms - temporary disturbances in Earth’s protective magnetic field.

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Channel: déjà vu  

105 minute night vision shoot around the constellation of Cepheus.
25 satellites filmed, 19 appear here with 12 identified including 3 relics from the 1960's.

Equipment used for filming-

Canon 60D through a Twiggy L4A1 + P8079HP image intensified F350mm telescope.

Satellite identified from the following sources.

Orbitrack and Redshift, live at time of filming and Heavens-above during editing.

© Music, ambient sounds and atmospherics created by déjà vu using DroneFX

Video length: 6:41
Category: Science & Technology

First Detection of Sugars in Meteorites Gives Clues to Origin of Life

NASA - OSIRIS-REx Mission patch.

Nov. 19, 2019

An international team has found sugars essential to life in meteorites. The new discovery adds to the growing list of biologically important compounds that have been found in meteorites, supporting the hypothesis that chemical reactions in asteroids – the parent bodies of many meteorites – can make some of life’s ingredients. If correct, meteorite bombardment on ancient Earth may have assisted the origin of life with a supply of life’s building blocks.

Image above: This is a mosaic image of asteroid Bennu, from NASA’s OSIRIS-REx spacecraft. The discovery of sugars in meteorites supports the hypothesis that chemical reactions in asteroids – the parent bodies of many meteorites – can make some of life’s ingredients. Image Credits: NASA/Goddard/University of Arizona.

The team discovered ribose and other bio-essential sugars including arabinose and xylose in two different meteorites that are rich in carbon, NWA 801 (type CR2) and Murchison (type CM2). Ribose is a crucial component of RNA (ribonucleic acid). In much of modern life, RNA serves as a messenger molecule, copying genetic instructions from the DNA molecule (deoxyribonucleic acid) and delivering them to molecular factories within the cell called ribosomes that read the RNA to build specific proteins needed to carry out life processes.

“Other important building blocks of life have been found in meteorites previously, including amino acids (components of proteins) and nucleobases (components of DNA and RNA), but sugars have been a missing piece among the major building blocks of life,” said Yoshihiro Furukawa of Tohoku University, Japan, lead author of the study published in the Proceedings of the National Academy of Sciences November 18. “The research provides the first direct evidence of ribose in space and the delivery of the sugar to Earth. The extraterrestrial sugar might have contributed to the formation of RNA on the prebiotic Earth which possibly led to the origin of life.”

Image above: 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. Image Credits: NASA's Goddard Space Flight Center Conceptual Image Lab.

“It is remarkable that a molecule as fragile as ribose could be detected in such ancient material,” said Jason Dworkin, a co-author of the study at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “These results will help guide our analyses of pristine samples from primitive asteroids Ryugu and Bennu, to be returned by the Japan Aerospace Exploration Agency’s Hayabusa2 and NASA’s OSIRIS-REx spacecraft.”

Image above: This is a model of the molecular structure of ribose and an image of the Murchison meteorite. Ribose and other sugars were found in this meteorite. Image Credits: Yoshihiro Furukawa.

An enduring mystery regarding the origin of life is how biology could have arisen from non-biological chemical processes. DNA is the template for life, carrying the instructions for how to build and operate a living organism. However, RNA also carries information, and many researchers think it evolved first and was later replaced by DNA. This is because RNA molecules have capabilities that DNA lacks. RNA can make copies of itself without “help” from other molecules, and it can also initiate or speed up chemical reactions as a catalyst. The new work gives some evidence to support the possibility that RNA coordinated the machinery of life before DNA.

“The sugar in DNA (2-deoxyribose) was not detected in any of the meteorites analyzed in this study,” said Danny Glavin, a co-author of the study at NASA Goddard. “This is important since there could have been a delivery bias of extraterrestrial ribose to the early Earth which is consistent with the hypothesis that RNA evolved first.”

The team discovered the sugars by analyzing powdered samples of the meteorites using gas chromatography mass spectrometry, which sorts and identifies molecules by their mass and electric charge. They found that the abundances of ribose and the other sugars ranged from 2.3 to 11 parts per billion in NWA 801 and from 6.7 to 180 parts per billion in Murchison.

Since Earth is awash with life, the team had to consider the possibility that the sugars in the meteorites simply came from contamination by terrestrial life. Multiple lines of evidence indicate contamination is unlikely, including isotope analysis. Isotopes are versions of an element with different mass due to the number of neutrons in the atomic nucleus. For example, life on Earth prefers to use the lighter variety of carbon (12C) over the heavier version (13C). However, the carbon in the meteorite sugars was significantly enriched in the heavy 13C, beyond the amount seen in terrestrial biology, supporting the conclusion that it came from space.

OSIRIS-REx artist's concept. Image Credit: NASA

The team plans to analyze more meteorites to get a better idea of the abundance of the extraterrestrial sugars. They also plan to see if the extraterrestrial sugar molecules have a left-handed or right-handed bias. Some molecules come in two varieties that are mirror images of each other, like your hands. On Earth, life uses left-handed amino acids and right-handed sugars. Since it’s possible that the opposite would work fine – right-handed amino acids and left-handed sugars – scientists want to know where this preference came from. If some process in asteroids favors the production of one variety over the other, then maybe the supply from space via meteorite impacts made that variety more abundant on ancient Earth, which made it more likely that life would end up using it.

The research was funded by a Japan Society for the Promotion of Science KAKENHI (science grant), the National Institutes of Natural Sciences Astrobiology Center, Japan, the Institute of Low Temperature Science, Hokkaido University, the Simons Foundation, and the NASA Astrobiology Institute, Goddard Center for Astrobiology. Jason Dworkin and Danny Glavin are members of the Goddard Center for Astrobiology team.

Related links:

Hayabusa2: http://www.hayabusa2.jaxa.jp/en/

OSIRIS-REx: https://www.nasa.gov/osiris-rex and

OSIRIS-REx (Origins Spectral Interpretation Resource Identification Security Regolith Explorer): http://www.nasa.gov/mission_pages/osiris-rex/index.html

Goddard Center for Astrobiology: https://astrobiology.gsfc.nasa.gov/

Proceedings of the National Academy of Sciences: https://www.pnas.org/content/early/2019/11/12/1907169116

Images (mentioned), Text, Credits: NASA/GSFC/Bill Steigerwald/Nancy Jones.

Greetings, Orbiter.ch

* This article was originally published here

Butterflies take different paths to arrive at the same colour pattern

An international team of scientists working with Heliconius butterflies at the Smithsonian Tropical Research Institute (STRI) in Panama was faced with a mystery: How do pairs of unrelated butterflies from Peru to Costa Rica evolve nearly the same wing-color patterns over and over again? The answer, published in Current Biology, forever changes the way evolution is understood.

Butterflies take different paths to arrive at the same colour pattern
Unrelated butterflies may have the same wing patterns. These patterns warn off predators and help suitors find the right
mate. But if wing patterns in each species evolved the same way, knocking out an important gene should have the same
 effect in both. Carolina Concha and her team discovered that knocking out the WntA gene results in different effects
in co-mimics, so the two species evolved the same pattern via different pathways
[Credit: Christian Ziegler]
"Our team is the first to report that although evolution of similar color patterns in Heliconius may be driven by similar forces--like predators avoiding a particular kind of butterfly--the pathway to that outcome is not predictable," said Carolina Concha, lead author of the paper and a post-doctoral fellow at STRI. "This really surprised us because it reveals the importance of history and chance in shaping the genetic pathways leading to butterfly wing-pattern mimicry."

Heliconius' bright wing colors signal to bird predators that the butterflies are toxic. Flashy male wing patterns signal to females that they are choosing the right species to mate with. Somehow these two forces, predation and mating, lead to similar wing patterns in groups of butterflies isolated in the mountain valleys and foothills of the Andes. By knocking out a single gene called WntA in 12 different species and their variants, the molecular biologists on the team could tell whether the butterflies in a pair with the same wing patterns were using the same genetic pathways to color and pattern their wings. They were not.

"Imagine two teams given the same Lego blocks are asked to build the same device," said Arnaud Martin, co-author and head of the Butterfly Evo-Devo Lab at George Washington University. "Each team goes about the task in a different way, but in the end, the result is the same. Butterflies face much more serious challenges: they build structures made of wing scales that are essential to their survival and ability to reproduce."

Questions regarding butterfly mimicry have intrigued biologists for decades, but the technology to selectively remove a single gene in a live organism did not exist until about five years ago. Now, with CRISPR/Cas 9 gene editing, it is getting much easier to tinker with the genetic code. When researchers knock out a major patterning gene like WntA, it changes the microscopic structure and color of the scales that compose the butterfly's wing and, as a result, the pattern changes. The study raises a number of questions, such as how WntA interacts with other genes to end up with an area that is red or black. Now the team wants to know how the WntA gene is controlled.

"We learned that while a developmental gene (WntA) can have a broad role in the evolution of most butterfly wing color patterns, its precise use to color a butterfly's wing is not completely predictable," said Riccardo Papa, co-author and professor at the University of Puerto Rico. "Distinct species with identical wing-color patterns, such as co-mimetic butterflies, can evolve using different molecular strategies. Imagine the same notes played on different instruments!"

"Some people say that Panama was an indigenous word meaning abundance of butterflies," said Owen McMillan, staff scientist and head of the ecological genomics lab at STRI. "The Smithsonian labs in Gamboa are certainly one of the best places in the world to understand how butterflies evolve, and we hope that inspired researchers will join us here as we continue to ask questions about these incredibly beautiful creatures."

Source: Smithsonian Tropical Research Institute [November 14, 2019]

* This article was originally published here

Agriculture and Disease Studies Ahead of Next Spacewalk

ISS - Expedition 61 Mission patch.

November 19, 2019

Today’s biology research aboard the International Space Station is helping scientists improve the health of astronauts in space and people on Earth. The Expedition 61 crew is also deploying a set of tiny satellites on Wednesday while getting ready for another spacewalk on Friday.

Flight Engineer Jessica Meir of NASA fed mice and watered plants today supporting a pair of long-running life science experiments. The rodent research study aims for cellular-level insights into diseases like cancer and diabetes to provide advanced therapies. The botany investigation explores the nutritional and morale-boosting benefits of growing fresh food in space.

Image above: NASA astronauts (from left ) Jessica Meir and Christina Koch are at the robotics workstation controlling the Canadarm2 robotic arm to support the first spacewalk to repair the Alpha Magnetic Spectrometer. Imge Credit: NASA.

NASA astronauts Christina Koch and Andrew Morgan recorded themselves with a 3-D video camera setting up gear that will deploy three small satellites outside Japan’s Kibo laboratory module. The deployer will eject the CubeSats in Earth orbit Wednesday morning to demonstrate technologies developed by several Asian nations.

Morgan and ESA (European Space Agency) commander Luca Parmitano are reviewing the tasks they will perform during this Friday’s spacewalk. They are continuing the intricate thermal control system repairs of the Alpha Magnetic Spectrometer, the station’s cosmic particle detector. Meir joined the duo at the end of the day and practiced the Canadarm2 robotics maneuvers to necessary support the spacewalkers.

Image above: Flying over Austral Ocean, seen by EarthCam on ISS, speed: 27'558 Km/h, altitude: 430,34 Km, image captured by Roland Berga (on Earth in Spain) from International Space Station (ISS) using ISS-HD Live Now application with EarthCam's from ISS on November 19, 2019 at 19:44 UTC. Image Credits: NASA/Orbiter.ch Aerospace.

Cosmonauts Alexander Skvortsov and Oleg Skripochka set up communications gear ahead of next month’s arrival of a Russian resupply ship. The duo also worked on station plumbing tasks before setting atmospheric observation gear.

Related article:

A very good start

Related links:

Expedition 61: https://www.nasa.gov/mission_pages/station/expeditions/expedition61/index.html

Rodent research study: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7906

3-D video camera: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7877

Kibo laboratory module: https://www.nasa.gov/mission_pages/station/structure/elements/japan-kibo-laboratory

Canadarm2: https://www.nasa.gov/mission_pages/station/structure/elements/mobile-servicing-system.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

Images (mentioned), Text, Credits: NASA/Mark Garcia/Orbiter.ch Aerospace/Roland Berga.

Best regards, Orbiter.ch

* This article was originally published here

Genes borrowed from bacteria allowed plants to move to land

Natural genetic engineering allowed plants to move from water to land, according to a new study by an international group of scientists from Canada, China, France, Germany, and Russia.

Genes borrowed from bacteria allowed plants to move to land
Microscopic image of Spirogloea muscicola, a new species of algae identified as part of a study that shows
how plants evolved to move from water to land [Credit: Barbara & Michael Melkonian]
"This is one of the most important events in the evolution of life on this planet--without which we as a species would not exist," said Gane Ka-Shu Wong, co-investigator and professor in the Faculty of Science and Faculty of Medicine & Dentistry at the University of Alberta. "The movement of life from water to land--called terrestrialization--began with plants and was followed by animals and then, of course, humans. This study establishes how that first step took place."

The movement of plants from water to land was made possible when genes from soil bacteria were transferred to algae through a process called horizontal gene transfer. Unlike vertical gene transfer, such as the transfer of DNA from parent to child, horizontal gene transfer occurs between different species.

"For hundreds of millions of years, green algae lived in freshwater environments that periodically fell dry, such as small puddles, river beds, and trickling rocks," explained Michael Melkonian, professor in the University of Duisburg-Essen in Germany. "These algae mingled with and received key genes from soil bacteria that helped them and their descendants to cope with the harsh terrestrial environment and eventually evolve into the land plant flora that we see today."

The study is part of an international project focused on sequencing the genomes of more than 10,000 plant species. The discovery was made in the process of sequencing two particular algae, one of them a new species (Spirogloea muscicola) being introduced to the community through this publication.

"The approach that we used, phylogenomics, is a powerful method to pinpoint the underlying molecular mechanism of evolutionary novelty," said Shifeng Cheng, first author and principal investigator from Agricultural Genome Institute at Shenzhen, Chinese Academy of Agricultural Sciences.

The study was published in Cell.

Author: Katie Willis | Source: University of Alberta [November 14, 2019]

* This article was originally published here

2019 November 20 Arp 273: Battling Galaxies from Hubble Image...

2019 November 20

Arp 273: Battling Galaxies from Hubble
Image Credit: NASA, ESA, Hubble; Processing & Copyright: Rudy Pohl

Explanation: What’s happening to these spiral galaxies? Although details remain uncertain, there sure seems to be a titanic battle going on. The upper galaxy is labelled UGC 1810 by itself, but together with its collisional partners is known as Arp 273. The overall shape of the UGC 1810 – in particular its blue outer ring – is likely a result of wild and violent gravitational interactions. The blue color of the outer ring at the top is caused by massive stars that are blue hot and have formed only in the past few million years. The inner part of the upper galaxy – itself an older spiral galaxy – appears redder and threaded with cool filamentary dust. A few bright stars appear well in the foreground, unrelated to colliding galaxies, while several far-distant galaxies are visible in the background. Arp 273 lies about 300 million light years away toward the constellation of Andromeda. Quite likely, UGC 1810 will devour its galactic sidekicks over the next billion years and settle into a classic spiral form.

∞ Source: apod.nasa.gov/apod/ap191120.html

* This article was originally published here

Lifelike chemistry created in lab search for ways to study origin of life

University of Wisconsin-Madison researchers have cultivated lifelike chemical reactions while pioneering a new strategy for studying the origin of life.

Lifelike chemistry created in lab search for ways to study origin of life
Under ultra-high magnification, the researchers found distinctive fractal shapes spreading along pyrite grains after
their chemical soups went through multiple generations. The researchers believe these fractals are salty deposits
 induced to form by a thin layer of organic material spread along the mineral [Credit: David Baum lab]
The work is far from jumpstarting life in the lab. Yet, it shows that simple laboratory techniques can spur the kinds of reactions that are likely necessary to explain how life got started on Earth some four billion years ago.

The researchers subjected a rich soup of organic chemicals to repeated selection by constantly paring down the chemical population and letting it build back up again with the addition of new resources. Over generations of selection, the system appeared to consume its raw materials, evidence that selection may have induced the spread of chemical networks capable of propagating themselves.

On longer timescales, these chemical changes oscillated in a repeating pattern. This boom-and-bust cycle isn't yet fully explained, but it is good evidence that the chemical soups established feedback loops resembling those found in living organisms. David Baum, a UW-Madison professor of botany, and his team published their findings in the journal Life. The work was funded by the National Science Foundation and NASA.

Now, other researchers can use this experimental approach and help untangle what components are necessary to encourage lifelike chemical systems and whether those chemical networks can go on to evolve more complex traits.

If this system can generate greater complexity, it might help solve the puzzle of how simple chemicals eventually gave rise to something as intricate as the cellular ancestor that spawned all life today.

"A core question in the origin of life is: How do you get evolution before there was genetic information like that within DNA or RNA?" says Baum. "What we've now realized is that the evolution of chemical networks may solve that problem, and that's something we can tackle in the lab."

Lifelike chemistry created in lab search for ways to study origin of life
The researchers subjected their chemical soups to a form of selection by taking a small amount of material from one
vial and placing it in a new vial with fresh pyrite and chemicals. After multiple generations, they found evidence
of chemical networks, represented in yellow, spreading quick enough to avoid dilution
[Credit: David Baum lab]
To test the idea of chemical ecosystem evolution, the researchers assembled a rich soup of chemicals. In seawater, they dissolved amino acids, sugars, common organic compounds, trace minerals and the building blocks of nucleic acids. To give the system even more of an edge, the scientists spiked the rich seawater with ATP, a high-energy molecule that drives nearly all of life's reactions today but was unlikely to exist in primordial times.

"Not all of these chemicals might have been available on early Earth, but we're trying to accelerate a process that could in theory get started from even simpler building blocks," says Baum, who is also a discovery fellow at the Wisconsin Institute for Discovery.

The team mixed their primordial soup with fine grains of pyrite, a mineral of iron and sulfur also known as fool's gold. Building on German chemist Gunter Wachtershauser's 1988 proposal of chemical evolution, Baum's team believes that pyrite is an ideal material for cultivating lifelike chemistry.

"Pyrite was a common mineral on primordial Earth, it can bind to a lot of organic compounds, and it can catalyze reactions between them," says Lena Vincent, a graduate student in Baum's lab and the lead author of the study. "And, very elegantly, a lot of highly conserved enzymes across life have cores that are very similar to pyrite. They're basically pyrite wrapped in protein."

The researchers added a few drops of the enriched seawater soup to a small amount of crushed pyrite in a vial and mixed the solution for a few days. This was the first generation. To begin the next generation, Vincent took a small amount of the first solution and mixed it into a vial with fresh soup and pyrite. Over a dozen or more generations, only those chemical networks that could propagate faster than they were diluted would survive and spread.

After 12 or 18 generations, the researchers saw a drop in available phosphate -- a readout of ATP use -- and in the dissolved organic material, which suggested that chemical compounds might be sticking to and spreading along the pyrite grains.

Lifelike chemistry created in lab search for ways to study origin of life
When the researchers extended their experiment to 40 generations, they spotted repeating oscillations in the concentration
of phosphate, one of the key starting materials in their chemical soups. These oscillations suggest the development
of feedback loops, which are one characteristic of life [Credit: David Baum lab]
When they inspected the pyrite under ultra-high magnification, the researchers saw an abundance of fractal shapes spreading along the surface of the mineral in the experimental samples but not in control samples that lacked a history of selection.

While these fractal shapes appear to be salts and are not likely to be lifelike themselves, the researchers suspect they may be induced by a thin smear of organic compounds bound to the grains. The fractals never appeared when organic material was left out of the solution.

"Scientists have been looking for examples of reactions that spontaneously complexify and organize organic chemicals for a long time," says Jim Cleaves, a co-author on the work from the Earth-Life Science Institute (ELSI) at the Tokyo Institute of Technology in Japan. "Based on this work, and other experiments we have been conducting at ELSI, it seems possible such reactions may not be incredibly rare at all, it may simply be a matter of using the right tools to find them."

When the researchers ran the experiment out to 40 generations, they observed periods of gradual change interspersed by sudden reversals to the starting conditions. While the cause of these crashes remains unknown, this kind of non-linear feedback loop is found across life and is evidence that the experimental system induced complex behaviors in the chemical soup.

"This non-linearity is a prerequisite for all the interesting lifelike behaviors we're looking for, including self-propagation and evolution," says Vincent. Cautiously excited with their preliminary success, Baum and his team are now eager to recruit others to help them refine their system.

"We wanted to develop a system that we can probe further to address questions about evolvability. And hopefully other labs will use this protocol and improve it," says Baum. "This is exactly where we wanted to be."

Author: Eric Hamilton | Source: University of Wisconsin-Madison [November 14, 2019]

* This article was originally published here

Bronze Age Kerb Cairn, Llyn Brenig, Denbighshire, North Wales, 17.11.19.

Bronze Age Kerb Cairn, Llyn Brenig, Denbighshire, North Wales, 17.11.19.

* This article was originally published here

Phoenix Cluster: A Weakened Black Hole Allows Its Galaxy to Awaken

Phoenix Cluster
Credit: X-ray: NASA/CXC/MIT/M.McDonald et al; Radio: NRAO/VLA; Optical: NASA/STScI

The Phoenix galaxy cluster contains the first confirmed supermassive black hole that is unable to prevent large numbers of stars from forming in the core of the galaxy cluster where it resides. This result, reported in our latest press release, was made by combining data from NASA's Chandra X-ray Observatory and Hubble Space Telescope, and the NSF's Karl Jansky Very Large Array (VLA). A new composite image shows data from each telescope. X-rays from Chandra depict hot gas in purple and radio emission from the VLA features jets in red. Optical light data from Hubble show galaxies (in yellow), and filaments of cooler gas where stars are forming (in light blue).

Composite - Phoenix Cluster
Credit: X-ray: NASA/CXC/MIT/M.McDonald et al; Radio: NRAO/VLA; Optical: NASA/STScI

Galaxy clusters are the largest structures in the cosmos that are held together by gravity, and they consist of hundreds or even thousands of galaxies embedded in hot gas and invisible dark matter. The galaxies in their centers of clusters contain the largest supermassive black holes known. In the case of the Phoenix Cluster, the black hole in its core has a mass equivalent to 5.8 billion suns.

For decades, astronomers have found such giant black holes pumping out energy into their environment, which keeps the gas that surrounds them too warm to form many stars. Previous work has shown that the largest galaxies in the universe lack cool gas in their centers and have many fewer stars than expected. The Phoenix Cluster is an example that bucks this trend. Instead, astronomers discovered a relatively cool current of gas along which many stars are being born.

The Phoenix Cluster system has several distinct elements that help tell the story of its unusually high star formation. Data from Chandra show that the coolest gas it can detect is located near the center of the cluster. In the absence of significant sources of heat, astronomers expect cooling to occur at the highest rates in a cluster's center, where the densest gas is located.

Optical observations with Hubble provide evidence for further cooling of gas near the center of the Phoenix Cluster. Ten billion solar masses of cooler gas are located along filaments to the north and south of the black hole, which likely originate from outbursts by the supermassive black hole located in the center of the image. The outbursts generated jets seen in radio waves by the VLA, in two opposite directions. As the jets push outward, they inflated cavities, or bubbles, in the hot gas that pervades the cluster. Chandra's sharp X-ray vision detected these cavities.

Phoenix Cluster
Credit: X-ray: NASA/CXC/MIT/M.McDonald et al; Radio: NRAO/VLA; Optical: NASA/STScI

The filaments of cool gas are located around the borders of the cavities, leading the authors to conclude that the black hole's outburst carries the gas away from the black hole. The farther away from the black hole, the faster the gas can cool to form stars. In the central part of the Phoenix cluster, stars are forming at a rate of about 500 solar masses per year. By comparison stars are forming in the Milky Way galaxy at a rate of about one sun's mass per year.

Eventually the black hole's outburst that is responsible for these jets will generate turbulence, sound waves and shock waves (similar to the sonic booms produced by supersonic aircraft). This will in turn provide a source of heat and prevent further cooling, until the outburst ceases and the build-up of cool gas recommences. The whole cycle can then repeat.

A paper describing these results was published in a recent issue of The Astrophysical Journal, and a preprint is available online. NASA's Marshall Space Flight Center manages the Chandra program. The Smithsonian Astrophysical Observatory's Chandra X-ray Center controls science and flight operations from Cambridge and Burlington, Massachusetts.

Fast Facts for Phoenix Cluster:

Scale: Image is about 45 arcsec (990,000 light years) across.
Category: Groups & Clusters of Galaxies, Quasars & Active Galaxies
Coordinates (J2000): RA 23h 44m 42.00s | Dec -42° 42´ 52.6"v Constellation Phoenix
Observation Date: 12 pointings from Sept 20, 2011 to Jan 25, 2018
Observation Time: 153 hours 7 min (6 days 9 hours 7 minutes)
Obs. ID: 13401, 16135, 16545, 19581-19583, 20630-20631, 20634-20636, 20797
Instrument: ACIS
Also Known As: SPT-CLJ2344-4243
References: McDonald, M. et al., 2019, ApJ, 885, 63; arXiv:1904.08942
Color Code: X-ray: Purple; Radio: Red; Optical: Orange (WFC/F850LP), Green (WFC/F755W), Blue (WFC/F475W)
Distance Estimate: About 5.8 billion light years (z=0.597)

* This article was originally published here

Lichens are way younger than scientists thought

You've probably seen a lichen, even if you didn't realize it. If you've ever meandered through the forest and wondered what the crusty stuff on trees or rocks was, they're lichens, a combination of algae and fungi living together almost as if they were one organism. And since they can grow on bare rocks, scientists thought that lichens were some of the first organisms to make their way onto land from the water, changing the planet's atmosphere and paving the way for modern plants. A new study in Geobiology upends this history by delving deep into the DNA of the algae and fungi that form lichens and showing the lichens likely evolved millions of years after plants.

Lichens are way younger than scientists thought
Crustose Ophioparma lichen [Credit: (c) Matthew P. Nelsen,
Field Museum]
"When we look at modern ecosystems, and we see a bare surface like a rock, oftentimes lichens are the first thing to grow there, and eventually you'll get plants growing on there too," says Matthew Nelsen, lead author of the paper and a research scientist at the Field Museum. "People have thought that maybe that's the way ancient colonization of land worked, but we're seeing that these lichens actually came later in the game than plants."

Four hundred and eighty-five million years ago, Earth was very different from what we see today. Hardly anything lived on land. But lichens can live in extreme conditions. They can grow on bare rocks and break them down, helping to create the soil needed by complex plants with roots (called "vascular plants"). Scientists thought that lichens must have arrived on land before the vascular plants did and made the environment more hospitable. But Nelsen and his colleagues' work calls this timeline into question.

Nelsen didn't set out to disrupt lichen's status as some of the land's first colonizers. He was initially interested in finding out how the algae-fungus relationship that makes up lichens came to be. If lichens could update their relationship status on Facebook, it would definitely be "it's complicated." They're a product of symbiosis, a relationship where two species live together and both benefit. In this instance, the algae--or specialized blue-green algae called cyanobacteria--provide food and the fungi wraps around it creating a shelter. "The question of when lichens evolved and how many times fungi evolved the ability to form symbiotic relationships with algae has been a bit contentious in the past," says Nelsen.

Lichens are way younger than scientists thought
Crustose Porpidia lichen growing on a rock [Credit: (c) Matthew P. Nelsen,
Field Museum]
But to accurately determine when lichens evolved, scientists needed to examine the evolutionary history of both the fungi and algae that make them up. The early lichen fossil record isn't very clear; it can be hard to tell lichen fossils apart from other fossils, and all the fossils that scientists know for sure are lichens are younger than the oldest complex plant fossils. So, the researchers used the fossils that were available to extrapolate the ages of family trees of lichen-forming fungi and algae. They compared these family trees with ages of fossil plants. The verdict: lichens probably evolved long after complex plants.

"Lichens aren't as old as we thought they were. They're a younger, newer sort of symbiosis and haven't been around forever, covering the earth long before there were plants and animals running around," says Nelsen.

Unearthing the age of lichens makes it clear that the pattern of modern lichens showing up on rocks before plants doesn't mean that lichens evolved before plants. "It provides a snapshot into what was going on deep in time on Earth, and when some of these groups started appearing," says Nelsen. And since lichens growing on soil can make the ground wetter, hold the soil in place, and influence the kind of nutrients present in soil, learning when lichens arrived on the scene use us a clearer picture of the world in which complex plants evolved.

By understanding what the Earth was like hundreds of millions of years ago, we can examine how it's changed and gain more insight into the current state of our planet. For the researchers, it's similar to the feeling you might get when learning about your family history from an ancestry DNA kit.

"It reshapes our understanding of the early evolution of complex ecosystems on Earth," says Nelsen.

Source: Field Museum [November 15, 2019]

* This article was originally published here

Subaru Telescope Detects the Mid-infrared Emission Band from Complex Organic Molecules in Comet 21P/Giacobini-Zinner

Figure 1: Comets are pristine remnants from the early Solar System. Comets are mostly made of ice and dust, but are also known to be rich in organic materials. If "complex" organic molecules like amino acids are enriched in comets and the meteoroids of cometary origin, the meteor showers might have delivered water and complex organic materials to the ancient Earth. (An artist's illustration. Credit: Kyoto Sangyo University)

Using the Cooled Mid-Infrared Camera and Spectrometer (COMICS) on the Subaru Telescope, astronomers have detected an unidentified infrared emission band from comet 21P/Giacobini-Zinner (hereafter, comet 21P/G-Z) in addition to the thermal emissions from silicate and carbon grains. These unidentified infrared emissions are likely due to complex organic molecules, both aliphatic and aromatic hydrocarbons, contaminated by N- or O-atoms. Considering the properties of the dust and organic molecules, comet 21P/G-Z might have originated from the circumplanetary disk of a giant planet (like Jupiter or Saturn) where it was warmer than the typical comet-forming regions.

Comet 21P/G-Z is a Jupiter-family comet with an orbital period of about 6.6 years and is thought to be the parent body of the October Draconids meteor shower. Compared to other comets, this comet is peculiar in terms of its volatile content (depleted in carbon-chain molecules, NH2, and highly volatile species) and the properties of its dust grains, and is categorized as "G-Z type" (~6% of surveyed comets). Based on previous studies, it was proposed that comet 21P/G-Z originated in a different region than other comets, but we didn’t have any information about the specific region in the protoplanetary disk. A negative trend of linear polarization in the optical wavelength region is also reported for the dust continuum of comet 21P/G-Z. It is suggested that this negative wavelength gradient of polarization might be explained by a higher content of organic materials in the dust grains of 21P/G-Z. If complex organic molecules like amino acids are enriched in comet 21P/G-Z and in the meteoroids of the October Draconids, this meteor shower might have delivered complex organic materials to the ancient Earth. However, complex high-molecular-weight organic molecules have never been detected clearly in comets, except in comet 67P/Churyumov-Gerasimenko by the in-situ measurements of the Rosetta spacecraft. How much and how complex of organic molecules are contained in comet 21P/G-Z is still an open question.

Figure 2: Comet 21P/Giacobini-Zinner observed in the optical on August 22, 2018
Credit: Michael Jaeger

A team of astronomers from the Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (ISAS/JAXA), Kyoto Sangyo University (KSU), National Astronomical Observatory of Japan (NAOJ), and Okayama University of Science (OUS) conducted mid-infrared spectroscopic and imaging observations of comet 21P/G-Z using COMICS on UT July 5, 2005 (when the comet was 1.04 au from the Sun, near its perihelion). The obtained spectrum of comet 21P/G-Z shows emission peaks of crystalline silicate grains, which are usually also seen in many other comets. In addition to these silicate features, the researchers found that the spectrum of comet 21P/G-Z exhibits unidentified infrared emission features, which could be attributed to a mixture of aliphatic and aromatic hydrocarbons (such as polycyclic aromatic hydrocarbons or hydrogenated amorphous carbons contaminated by N- or O-atoms).

Comet 21P/G-Z is enriched in complex organic molecules. The enrichment of complex organic molecules requires a warm temperature or high energetic particle environment around the comet in the early solar nebula. The presence of these complex organic molecules suggests that comet 21P/G-Z originated from a warmer region in the protoplanetary disk than the typical comet-forming region. Considering that the derived mass fraction of crystalline silicates in comet 21P/G-Z is typical of comets, we propose that the comet originated from the circumplanetary disk of a giant planet (like Jupiter or Saturn) where it was warmer than the typical comet-forming region (5–30 au from the Sun) and was suitable for the formation of complex organic molecules. Comets from circumplanetary disks might be enriched in complex organic molecules, similar to comet 21P/G-Z, and may have provided pre-biotic molecules to ancient Earth by direct impact or meteor showers.

Figure 3: Blackbody normalized mid-infrared spectra of comets. The spectrum of comet 21P/G-Z (black filled circles) is different from other comets, and exhibits unidentified infrared emission features. The features at ~8.2 microns, ~8.5 microns, and ~11.2 microns could be attributed to PAHs (or HACs) contaminated by N- or O-atoms, although part of the feature at ~11.2 microns comes from crystalline olivine. The feature at ~9.2 microns might originate from aliphatic hydrocarbons. (Credit: Ootsubo et al.). 

These results were published on November 18, 2019 in Icarus (Ootsubo et al., "Unidentified Infrared Emission Features in Mid-infrared Spectrum of Comet 21P/Giacobini-Zinner"). This research paper is also available as a preprint (Ootsubo et al., arXiv:1910.03485) on arxiv.org. This study is financially supported by MEXT Supported Program for the Strategic Research Foundation at Private Universities, 2014-2018 (No. S1411028). T.O. is supported by JSPS KAKENHI Grants-in-Aid for Scientific Research (C) JP17K05381 and (A) JP19H00725.


* This article was originally published here


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