Australian PM may not join climate summit: report

Issued on: 27/09/2021 - 

Australia, the world's biggest coal exporter and still reliant on the fossil fuel for most of its electricity, has not made a firm commitment on its greenhouse gas reductions

 GREG WOOD AFP/File

IT'S MINERS ARE MOVING INTO ALBERTA, SASK. AND ONTARIO'S RING OF FIRE

Sydney (AFP)

Australian Prime Minister Scott Morrison, under pressure to adopt a 2050 net-zero carbon emissions target, said in an interview published Monday that he may not join this year's landmark UN climate summit in Glasgow.

The world's biggest coal exporter and still reliant on the fossil fuel for most of its electricity, Australia has not made a firm commitment on its own greenhouse gas reductions. Morrison has vowed to mine and export fossil fuels as long as there are buyers.

Asked about attending the global climate crisis conference in November, Morrison told the West Australian newspaper: "We have not made any final decisions."

"I mean it is another trip overseas and I have been on several this year and spent a lot of time in quarantine," he was quoted as saying.

"I have to focus on things here and with Covid. Australia will be opening up around that time. There will be a lot of issues to manage and I have to manage those competing demands."

The 12-day meeting in Scotland, the biggest climate conference since landmark talks in Paris in 2015, is seen as a crucial step in setting worldwide emissions targets to slow global warming.

Morrison's government has suggested it will achieve net-zero carbon emissions "as soon as possible", and preferably by 2050, but has not made any commitments to do so.

The Australian prime minister told the paper he was trying to bring the government and the country together on future commitments so as to provide certainty for the next 20-30 years.

He has been in tough negotiations over setting a net-zero target within the conservative coalition government, an alliance of his own Liberal Party and the Nationals, who have much of their support base in rural and mining communities.

Climate scientists warn extreme weather and fierce fires will become increasingly common due to manmade global warming.

Environmentalists argue inaction on climate change could cost Australia's economy billions of dollars as the country suffers more intense bushfires, storms and floods.

Asked if he would commit to a specific climate target in a separate interview with The Australian newspaper, the prime minister replied: "I can assure you we will have a plan."

Morrison told the paper that Australia's position as the primary energy exporter in the Asia-Pacific region would change and it was important to make a transition towards a low-emission economy.

The prime minister added, however, that the change had to be managed so "things keep running, things stay open, things keep getting dug out of the ground for some considerable time, you have to keep making stuff, you have to keep eating things and the world needs food".

MORE MODERN THAN THE USA
San Marino voters approve abortion three to one in referendum

Issued on: 27/09/2021 -

Des membres de la campagne pour le "oui" à Saint-Marin, dimanche 26 septembre. 

© Jennifer Lorenzini, Reuters

The tiny state of San Marino voted Sunday to allow abortion in a historic referendum result that will bring the predominately Catholic nation in line with most of the rest of Europe.

Some 77.3 percent of voters approved a motion to allow the termination of a pregnancy up to 12 weeks.

After that, abortion would only be allowed if the mother’s life was in danger or in the case of foetal abnormalities that could harm the woman physically or psychologically.

The picturesque republic of San Marino, situated on a mountainside in the centre of Italy, is one of the last places in Europe along with Malta, Andorra and the Vatican to have a total ban on abortion.

In traditionally Catholic Ireland, abortion was made legal in 2018, also after a referendum.

There were celebrations at Sunday’s result among members of the San Marino Women’s Union (UDS), which had initiated the referendum and campaigned for a “Yes” vote against the governing party and the Catholic Church.

“It’s a victory for all the women of San Marino, over the conservatives and reactionaries who believe women have no rights,” UDS president Karen Pruccoli told AFP.

“It’s a victory against the Catholic Church who were our opponents and tried everything to prevent this result.”

More than 35,000 people were eligible to vote in Sunday’s referendum, around one third of them based abroad. The turnout was 41 percent, some 14,500 people.

‘Respect the result’

In the absence of opinion polls, nobody had wanted to predict the result in a country where the influence of the Church remains strong.

Pope Francis last week reiterated his uncompromising position that abortion is “murder”.

The campaign to vote “No” on Sunday was led by the ruling Christian Democratic Party, which has close ties to the Catholic Church.

“It’s a defeat for a country that has always defended life,” the party’s deputy secretary Manuel Ciavatta told AFP after the result.

But he said the government would propose a law within six months to implement the abortion change, that would then be put to parliament.

“We respect the voice of the voters,” he said, while adding: “Our party will do everything it can to help women to ensure they are not left alone.”

Currently, abortion carries a penalty of up to three years in prison for the woman and six years for the doctor who conducts the procedure.

However, nobody has ever been convicted.

Women who choose to have an abortion typically cross into Italy, where it has been legal for more than 40 years.

Before the result came in, Francesca Nicolini, a 60-year-old doctor and member of UDS, had argued: “The majority of young people are on our side, because it’s an issue that directly affects their lives.

“It’s unacceptable to view as criminals women who are forced to have abortions.”

Radical change

The vote signals a radical change for San Marino, where the ban dates back to 1865 and was confirmed by both the fascist regime in the early 20th century and then again in 1974.

Figures from Italy suggest few women from the tiny state cross the border to take advantage of the abortion laws there.

Between 2005 and 2019, only about 20 women a year from San Marino had abortions in Italy, falling to 12 in 2018 and seven in 2019, according to official Istat data cited by the campaigners against abortion.

This is still too many for opponents such as Rocco Gugliotta, a 41-year-old warehouse worker, who asked: “Why should only the mother decide?”

However, Alfiero Vagnini, a 65-year-old cook, was among the “Yes” voters, explaining: “On many subjects, San Marino is behind. We need to become a more modern country.”

(AFP)

Inside South Africa's deadly initiation rituals

Across Africa, many cultures mark the transition from boyhood to manhood with initiation rituals. In South Africa, the secretive initiation season results in the deaths of dozens of young boys every year and leaves hundreds more terribly injured.

This One Tiny Animal Has Found a Way to Give Up Sex Completely, And Still Do Fine

Oppiella nova up close. (M. Maraun and K.Wehne)

NATURE
MIKE MCRAE
25 SEPTEMBER 2021

Let's face it. Sex isn't always worth the effort. For many animals, the whole mating game is so inconvenient, going it alone and reproducing asexually is the best option.

As appealing as it might sound, however, evolution puts a heavy price on a population that gives up sex for too long. Sooner or later, a eukaryotic species will either need to swap chromosomes in a DNA shake-up that increases genetic variation, or risk fading into extinction.

That's the rule, at least – but the beetle mite (Oppiella nova) is having none of it.

By comparing its genome with that of its sexually active cousin, O. subpectinata, a team of researchers from across Europe has found that this micrometer-sized arthropod has been doing quite all right living a chaste lifestyle for... millions of years.

Like us, these tiny mites have a copy for every chromosome making up their genome, which makes them a diploid organism.

Swapping chromosomes and subjecting them to a bit of mix-and-match every now and then helps give a population a diverse choice in genetic combinations, meaning when catastrophe strikes – be it a plague, a temperature change, or introduction of a new predator – there's bound to be at least a few individuals that will cope.

Strip away all the bells and whistles, and that's sex all summed up. Unfortunately, those bells and whistles (searching out mates, competing with them, producing all that sperm, the whole pregnancy thing) impose a toll on maximizing genetic diversity.

There are other ways to maintain a degree of variation that don't rely on sexual reproduction. These processes cause mutations to build up differently in types of the same gene (or allele), creating a unique signature among the genes of asexual organisms.

Known as the Meselson effect, named after Harvard geneticist Matthew Meselson, this mutation pattern could in theory be used to identify a diploid organism as a bona fide, long-term asexual species.

The only problem is none of the evidence for this effect has been clear-cut, leaving too much room for doubt. Some ancient lineages of species thought to be asexual have since been found to have only recent converts, or – scandalous as it is to suggest – have peppered their genes with the occasional licentious tryst over the eons.

What researchers needed was a strong, unambiguous signal of variation in genes in an animal suspected of having given up sex long, long ago, and never looked back.

Which brings us back to O. nova – a little mite with sublineages that went their separate ways between 6 and 16 million years ago, suggesting it's a species that's been around for quite a while.

More importantly, it's a species known to be asexual, in contrast with others on its branch of the family tree, making it a prime specimen to study for evidence of the Meselson effect.

As one might imagine of an animal that could form a conga-line inside a single millimeter, the task of collecting them and analyzing their DNA wasn't exactly easy.

"These mites are only one-fifth of a millimeter in size and difficult to identify," says reproductive biologist Jens Bast from the University of Lausanne in Switzerland.

The team even required specialized computer programs to decipher the genomes, but it was all worth it in the end.

"Our results clearly show that O. nova reproduces exclusively asexually," says Bast.

"When it comes to understanding how evolution works without sex, these beetle mites could still provide a surprise or two."

This isn't to say asexual reproduction isn't without its problems. The beetle mite appears to be an exception to an otherwise fairly consistent rule in biology.

But the discovery of an animal that's managed to leave sex millions of years in the past does demonstrate it's possible to thrive without it.

This research was published in PNAS.

The social life of a vampire bat

=REUTERS
SEPTEMBER 25, 2021 



Bonding: Captive bats once released were found to join a “friend” during foraging. 

Photo Credit: reisegraf;iStockphoto

Each bat in the colony has its own network of social bonds

When one thinks of the blood-feasting vampire bats, friendship and cooperation may not be among the qualities that come to mind But perhaps they should.

Scientists have shown how those bats that have forged “friendships” with others will rendezvous with these buddies while foraging for a meal.
Studying female bats

Researchers attached small devices to 50 vampire bats to track night time foraging in Panama, when these flying mammals drink blood from wounds they inflict upon cattle in pastures. The study involved female bats, known to have stronger social relationships than males.

Among the bats were 23 wild-born individuals that had been kept in captivity for about two years during related research into bat social behaviour. Social bonds already had been observed among some of them. After being released back into the wild, the bats were found to often join a “friend” during foraging,possibly coordinating the hunt.

“Each bat maintains its own network of close cooperative social bonds,” said behavioral ecologist Gerald Carter of the Ohio State University and the Smithsonian Tropical Research Institute, who led the research published in PLoS Biology.

Social bonds

Social bonds among vampire bats as they roost in trees include grooming one another and regurgitating blood meals for hungry pals. The study showed that the social bonds formed in roosts extended into the hunt.

The researchers suspect that the bats, while almost never departing on foraging forays with their “friends,” link up with them during the hunt for mutual benefit. They hypothesise the bats might exchange information about prey location or access to an open wound for feeding.
Live in colonies

Vampire bats, which inhabit warmer regions of Latin America and boast wingspans of about 18 cm, are the only mammals with a blood-only diet. They reside in colonies of thousands.

“Even besides their social lives, vampire bats are quites pecial: specializing in a diet of 100% blood is already quite rare among vertebrates,” said co-author Simon Ripperger, a post-doctoral researcher from Smithsonian Tropical Research Institute. “They are amazing runners, which you wouldn’t expect in a bat. They have heat sensors in their snouts that help them find a spot to make a bite.”

 

Remains of organic molecules are found in the nucleus of ancient dinosaur cells

• Sneha Mali
 
• September 25, 2021
 
•  Sci/Tech

A team of scientists from the Chinese Academy of Sciences’ Institute of Vertebrate Paleontology and Paleontherology (IVPP) and the Shandong Tianyu Museum of Nature (STM) have preserved the finest 125 million-year-old dinosaurs in the northeast. China containing nuclei containing organic molecules and chromatin residues. The study was published September 24 in Communications Biology.

A dinosaur named Caudipteryx was a small peacock-shaped omnivore with long tail wings. During the early Cretaceous, they roamed the shores of the shallow lakes of Jehol Biota in Liaoning Province.

“Geological data has been accumulated over the years and it has been shown that fossil defenses in Jehol Biotta were exceptional because the bodies were trapped by fine volcanic ash and were preserved at the cellular level,” said Li Zhiheng, associate professor of IVPP and co-author of the study.

Scientists removed a piece of distal articular cartilage from the right thigh of this specimen, decomposed it, and used various microscopy and chemical methods to analyze it. After the death of the animal, they realized that all the cells had been mineralized by selection. This silicification most likely allows for the best preservation of these cells.

They also discovered two main types of cells: cells that were healthy at the time of the fossil, and healthy cells that were porous and non-fossilized in the process of dying. “It’s possible that these cells were dying before the animals died,” said Alida Baleul, an associate professor at IVPP and co-author of the study.

Cell death is a process that occurs naturally in the lives of all animals. But being able to place fossil cells in a specific place in the cell cycle is very new in paleontology. IVPP scientists have one goal: to improve cellular images in fossils.

Furthermore, the team isolated some cells and stained them with chemicals used in biological laboratories around the world. This purple chemical called hematoxylin is attached to the nuclei of cells. After staining the dinosaur material, a dinosaur cell showed a purple nucleus containing some dark purple threads. This means that a nucleus in a 125 million-year-old dinosaur cell is so well preserved that it retains some of the original bio-molecules and chromatin threads.

Chromatin is made up of tightly packed DNA molecules in the cells of all living things on Earth. The results of this study thus provide preliminary data that suggest that remnants of the original dinosaur DNA can still be preserved. But to test this precisely, the team needs to do a lot more work and use chemical methods that are more sophisticated than the stains they use here.

“Let’s be honest, we’re clearly interested in fossil cell nuclei because most DNA should be there if DNA is protected.” Last year she published another study reporting exceptional molecular and biomolecular protection in dinosaur cartilage cells in Montana. “So, we have good basic data, very exciting data, but we’re starting to understand cellular biochemistry even in older fossils. At this point, you need to do more work.”

The team insists they need to do more analysis and develop new methods to understand the processes that allow biomolecular protection in dinosaur cells, as no one has ever successfully sequenced dinosaur DNA. In the ancient DNA community, sequence methods are used to confirm whether ancient DNA is preserved in fossils. So far, these methods have only worked for young fossils (not more than a million years old), but they have never worked for dinosaur material. Dinosaurs are considered too old to preserve any DNA. However, the chemical data collected by scientists from IVPP and STM suggest otherwise.

Although more data needs to be collected, this study clearly shows that 125 million-year-old fossil dinosaur cells cannot be considered 100% rock. They are not completely “stoned”. Instead, it still contains remnants of organic molecules. Now, it is essential to find out exactly what these molecules are, whether they retain any biological information and DNA remnants.

These dinosaur diseases, which might seem familiar, reveal how they lived and died

Katie Hunt
CNN Digital
Thursday, September 23, 2021 

The lower jaw of SUE the T. rex is pitted with holes that experts believe were the result of a parasitic infection. (Source: Koichi Kamoshida / Getty Images via CNN)

Tyrannosaurus rex battled parasites and got gout from its meat-rich diet. Duck-billed hadrosaurs suffered cancerous tumours, and a towering sauropod in China survived a nasty pus-filled infection from a predator bite.

Dinosaurs, like us, got sick and injured. By detecting these medical conditions in fossils, paleopathologists, experts in ancient disease and injuries, are gaining tantalizing insights into dinosaur behaviour and evolution -- how a dinosaur moved through its world, the relationship between predator and prey, and how dinosaurs of the same species interacted.

Until relatively recently, however, diagnosing multi-million-year-old diseases from fossilized bones was decidedly hit-and-miss.

First off, the fossil record only reveals a small fraction of the creatures that lived in the past, and those that reach us have withstood multiple obstacles over millions of years. What's more, with soft tissue largely missing from fossils, scientists rely on bones for information. And it's often very hard to determine whether deformations in a dinosaur's bone structure were caused by disease or the crush of sediment over time.

Paleontologists can identify strange structures, bone overgrowths, rough surfaces, and holes or porous surfaces in areas where they should not be without the help of special tools. But the application of medical advances like computerized tomography to paleontology have allowed researchers to peer through rock to see what's happening inside fossilized bones.

"It's imperative to have an inner view of the bone," said Filippo Bertozzo, a post-doctoral researcher at the Royal Belgian Institute of Natural Sciences in Brussels. "If you have doubts whether a bone is deformed by pathology or geological processes, you need to see inside."

"If it's geology at play, you wouldn't see any change in the structure of the cells."

Often it takes a raft of experts in different fields to confirm a diagnosis. Think of an episode of the television series "House" for dinosaurs.

"The study of paleopathologies is more than simply identifying a disease, it is opening a window to learn about interactions with the environment and social behaviour," said Penélope Cruzado-Caballero, a paleontologist at the Research Institute of Palaeobiology and Geology of CONICET, Argentina's National Council for Scientific and Technical Research, and the National University of Río Negro (Argentina).

For example, paleontologists had long been stumped by the unusual domed skulls of Pachycephalosaurs -- small, plant-eating dinosaurs that are bit players in the "Jurassic Park" movie franchise. The discovery of bone lesions resulting from injuries in adults suggested that they used the domes to butt heads -- a bit like big-horned sheep do.

NOT JUST BIG, BUT TOUGH

The most commonly detected pathology in the dinosaur fossil record is bone fractures -- with some dinosaurs apparently surviving very severe trauma that must have left them living in great pain.

Bertozzo has detailed the injuries suffered by one Parasaurolophus walkeri, a dinosaur with a long, curved crest. Its fossil was unearthed in 1921 and has been on display at the Royal Ontario Museum in Toronto for decades.

For years, paleontologists had thought a V-shape indentation in the dinosaur's spine was part of its natural posture -- perhaps to accommodate its long, dramatic headgear.

A new analysis published in 2020 found that the dent was due to a broken back. The creature also had broken ribs, a deformed pelvis and a dental lesion. Bertozzo believes the broken back was possibly caused by a falling rock or tree, but the dinosaur didn't die of its injuries -- at least not immediately. Bertozzo said it would have lived at least four months, and their analysis suggested the injuries had begun to heal before the creature's death.

Bertozzo believes that some dinosaurs must have been able to overcome and survive massive injuries. He said one hypothesis is that a strong immune system was a survival mechanism for some herbivores, like Hadrosaurs, which didn't have defensive features like armored plates, spiked tails or sharp horns common in other plant-eating species, such as Triceratops.

Dinosaurs also lived with cancer -- in some cases the same form that afflicts humans today. A horned dinosaur called Centrosaurus apertus that lived 76 to 77 million years ago in what's now Alberta, Canada, was diagnosed in a study published in 2020 with osteosarcoma -- an aggressive malignant bone cancer that can affect humans.

Researchers concluded it was an advanced stage of cancer that may have spread throughout the dinosaur's body. But what might have been a death sentence for one dinosaur, another could endure.

Cruzado-Caballero diagnosed the same cancer in Bonapartesaurus, unearthed in Argentinean Patagonia in the 1980s. This dinosaur had a large cauliflower-like overgrowth of bone on its foot but, she said the growth hadn't spread to other parts of the animal's body, and she didn't think it would have seriously affected its day-to-day life. Likely more painful were two fractures in its tail, which healed in an abnormal position and may have been infected while healing, said Cruzado-Caballero, who is also a professor at the University of La Laguna in Tenerife, Spain.

STARVING T. REX

T. rex was the ultimate dinosaur predator, weighing as much as two African elephants, but it could fall victim to the tiniest of foes: parasites.

The lower jaw of SUE the T. rex, the most complete T. rex skeleton ever found, was pitted with smooth-edged holes. Initially experts thought they were bite marks or a bone infection, but researchers ultimately concluded the holes were a result of a parasitic infection called trichomonosis. The condition can also effect the lower jaw of modern birds like pigeons, doves and chickens.


"The parasite effectively eats chunks of the jaw bone. This extremely nasty condition causes severe damage and pain around the mouth, throat and esophagus, making simple things like eating and drinking unpleasant to nearly impossible," said Dean Lomax, a paleontologist at the University of Manchester's Department of Earth and Environmental Sciences, in his book, "Locked in Time: Animal Behavior Unearthed in 50 Extraordinary Fossils."

"Once the animal was infected, feeding would have been difficult, and it is highly likely that, as seen in living birds, the mighty tyranosaurs lost considerable weight before eventually starving to death."

While SUE the T. rex, who is on display at Chicago's Field Museum, may have starved to death, paradoxically the dinosaur also suffered another medical problem that in humans is linked with overindulging in food and wine.

Gout is a form of inflammatory arthritis caused by buildup of uric acid, which can erode bones. SUE's right forearm had "gouty lesions," according to a report in Nature. The condition in animals today, including birds and reptiles, can be the result of dehydration or kidney failure. In humans, it's associated with foods that have a high purine content, such as red meat -- something that no doubt made up the bulk of T. rex meals.

COULD DINOSAURS HAVE BEEN ATTACKED BY CORONAVIRUSES?

It's also possible that dinosaurs suffered from respiratory diseases, such as pneumonia, or contagious ones like tuberculosis, although it's unclear whether dinosaurs contracted diseases similar to COVID-19. The oldest suspected case of a respiratory disease of any kind is from a 245-million-year old marine reptile.

"Birds, especially pet birds, do suffer from pulmonary infection. Birds are dinosaurs, and dinosaurs presented, most likely, a birdlike lung system," Bertozzo said. "I would expect dinosaurs to suffer from similar pulmonary infections as in birds. Of course, COVID is a novel disease, we cannot know if something similar happened in the past, so we can't say if dinosaurs suffered from COVID-like diseases."

Bertozzo is building a database to record incidences of trauma and disease across different species of ornithopods -- a family of plant-eating dinosaurs that includes iguanadons, hadrosaurs and duck-billed dinosaurs -- and across different time periods. He hopes it will help answer questions like which group of these dinosaurs was most likely to suffer disease and whether these conditions affected dinosaur behaviour.

"It's a growing field that is going to give us a lot information about the lives of these fascinating creatures," he said.

The tubular crest of Parasaurolophus is on display at the Royal Ontario Museum in Toronto.

 (Source: Education Images / Universal Images Group Editorial / Getty via CNN

Weatherwatch: the threat to Trident from global heating

Rising sea levels present a hazard to the UK’s nuclear deterrent that could cause a major accident

HMS Vigilant, a Vanguard-class nuclear submarine, docked at HMNB Clyde in Faslane, Scotland. 

Photograph: Danny Lawson/PA

Paul Brown
Sat 25 Sep 2021 

The US has acknowledged that global heating is a significant threat to its defence capability, with 79 military bases, including 23 nuclear installations, subject to sea level rise and frequent flooding.

While the UK has far fewer military bases to worry about, the key Trident nuclear deterrent requires a submarine to be constantly at sea ready for action. A series of coastal sites is needed to keep these boats and their weapons serviced at all times.

In 2010, a UK National Security Strategy acknowledged that sea-level rise was a hazard to this programme that could cause a major accident. In the 11 years since then, nothing seems to have happened to address the problem even though the estimates of future sea level rise and storm surges have become ever more alarming.

The Nuclear Consulting Group, an independent group of academics, has produced a helpful report on the threats to Britain’s nuclear bases in 2050. The maps showing potential danger to vital bases are not based on alarming upper level predictions but the more conservative middle range.

Worst affected by flooding are the naval base at Faslane, which is 25 miles from Glasgow and where the nuclear-armed submarines are based, and the shipyard at Barrow-in-Furness in Cumbria where they are built and fuelled.

 

Record High Temperatures In The Pacific Likely The Reason Behind Last Year’s Massive Hole In Arctic Ozone

New analysis suggests a high chance of it being a regular occurrence in the future.

By Dese Gowda  September 24, 2021 

 

Early last year, an unusually large hole opened up in the ozone layer over the Arctic, encompassing an area of up to 1 million square km, albeit smaller than the Antarctic ozone hole, which is roughly around 20 to 25 million square kilometers in area.

Although the hole closed by springtime, two months after opening up, it left scientists puzzled about the cause behind it.

A new analysis performed by scientists from the Department of Atmospheric and Oceanic Science at Peking University seems to point at record-breaking temperatures in the North Pacific Ocean during winter as the cause behind the unusual occurrence. The analysis published in the journal Advances of Atmospheric Sciences, suggests high chances of it being a regular occurrence in the future.

The researchers ran a series of simulations using satellite data and found high sea surface temperatures during winter in the North Pacific Ocean caused lowered temperatures of the Arctic westerly winds.

These winds blow through the region throughout winter up until spring and can trigger polar cloud formation if their temperatures are cold enough for long periods.

Cloud formation in the stratosphere in the North and South poles plays a key role in severely depletion ozone. Unlike over the Antarctic, the stratospheric vortex in the Arctic is usually too warm for polar stratospheric cloud formation.

The researcher found that during February and March 2020, North Pacific ocean surface temperatures led to a reduction of planetary wave activity, which in turn caused extremely cold and persistent stratospheric polar vortex during the same period.

According to Prof. Yongyun Hu, lead author of the study, the record Arctic ozone loss in spring last year indicates that substances that deplete ozone in present-day are still sufficient to cause springtime depletion. The results of the analysis indicate that ozone loss is most likely to be a recurring phenomenon.

Cover Image: Depletion of zone levels over the Arctic between March and April 2020. Credit: Copernicus/ESA

 

Formation Of Earth And Venus Was A Messier Affair Than Previously Thought

Planets within the inner solar system likely formed after repeated hit-and-run collisions, potentially upending current models of planet formation.

By Dese Gowda  September 24, 2021 

The formation of planets in the inner solar system was messier and complicated than previously thought, according to a new paper.

Planets such as Earth and Venus were previously thought to have formed when smaller rocks, asteroids, and debris, collide and stick together to form a neat, round planet, which further grew as it accumulated more mass from further collisions.

The new research suggests that much of the planets within the inner solar system were likely formed after repeated hit-and-run collisions, potentially upending current models of planet formation.

The paper published in the journal, The Planetary Science focuses on two of the biggest planets within the inner solar system – Earth and Venus and the Earth’s moon. In the paper, the researchers argue that giant impacts are not efficient in merging masses as previously believed by scientists.

They propose a scenario where pre-planetary masses repeatedly crashed into and ricocheted off each other, before colliding with each other again at a later time. Having been slowed down by the first collisions, the objects would be able to stick together better the second time.

According to Erick Asphaug, lead author of the paper and professor at Lunar and Planetary Laboratory, most giant impacts, even relatively “slow” ones, are hit-and-run collisions and won’t lead to colliding masses sticking together. For two planets or rocks to merge, they usually have to slow down first. For instance, it probably took collisions for the moon to form.

The paper suggests that the planets Venus and Earth would have had completely different experiences during their formation, despite being neighbours.

The solar system is a gravity well; the closer a planet is to the sun, the stronger the gravitational pull from the sun experienced by the planet. Hence, when objects move closer to the sun, they are more likely to stay there. Therefore, a young Earth acted as a vanguard to Venus, slowing down and bouncing away bodies colliding with it for the first time, making it more like for them to be absorbed by Venus.

Cover Image: Shutterstock

Ancient impact that formed Earth's moon was likely a one-two punch

Twice the cosmic violence!

By Mike Wall 2 days ago

Earth's moon is thought to have formed when a Mars-sized object, called Theia, slammed into the proto-Earth more than 4.4 billion years ago, blasting out material that later coalesced into a large satellite as depicted in this artist's illustration.

 (Image credit: NASA/JPL-Caltech)

The gigantic impact that created the moon was actually a one-two punch, a new study suggests.

Scientists think that the moon, our planet's only natural satellite, was born in violence, coalescing from the material blasted into space after a Mars-size body named Theia slammed into the proto-Earth more than 4.4 billion years ago.

But there are some problems with the canonical collision scenario, which invokes a single catastrophic event, the authors of the new study said.

"The standard model for the moon requires a very slow collision, relatively speaking, and it creates a moon that is composed mostly of the impacting planet, not the proto-Earth, which is a major problem since the moon has an isotopic chemistry almost identical to Earth," lead author Erik Asphaug, a professor at the University of Arizona's Lunar and Planetary Laboratory (LPL), said in a statement.

Related: How was the moon formed?

The moon is thought to be the aftermath of a giant impact. According to a new theory, there were two giant impacts in a row, separated by 100,000 to 1 million years, involving a Mars-sized body called Theia and proto-Earth. In this image, the proposed hit-and-run collision is simulated in 3D, shown about an hour after impact. A cut-away view shows the iron cores. Theia (or most of it) barely escapes, so a follow-on collision is likely.

 (Image credit: A. Emsenhuber/University of Bern/University of Munich)

Double whammy made the moon

Asphaug and his colleagues performed computer simulations of the long-ago giant impact and came up with what they believe to be a better fit: Theia and the proto-Earth crashed at faster speeds than previously envisioned, producing an initial "hit and run" collision that set the stage for a slower, accretionary encounter between the two battered bodies about 100,000 to 1 million years down the road.

"The double impact mixes things up much more than a single event, which could explain the isotopic similarity of Earth and moon, and also how the second, slow, merging collision would have happened in the first place," Asphaug said.

Hit-and-run collisions weren't restricted to the nascent Earth-moon system in those early days. Indeed, such bouncing smashups were probably about as common as accretionary mergers in the ancient inner solar system, the same research team reports in a second new study.

In the second paper, the scientists modeled giant impacts in the inner solar system, how those collisions affected planet formation and how the orbits of the involved objects evolved over time. They found that Earth likely acted as a sort of shield for Venus, taking the brunt of hit-and-run first impacts. Those initial collisions slowed the impactors down, setting the stage for accretionary mergers with Venus later.

"The prevailing idea has been that it doesn't really matter if planets collide and don't merge right away, because they are going to run into each other again at some point and merge then," Alexandre Emsenhuber, the lead author of the second study, said in the same statement.

"But that is not what we find," said Emsenhuber, who performed the research during a postdoctoral fellowship in Asphaug's lab at LPL and is now at Ludwig Maximilian University in Munich, Germany. "We find they end up more frequently becoming part of Venus, instead of returning back to Earth. It's easier to go from Earth to Venus than the other way around." (This is because Venus lies closer to the sun, whose powerful gravity draws objects in.)

The results suggest that the compositions of Earth and Venus may differ more than scientists had thought.

"You would think that Earth is made up more of material from the outer system because it is closer to the outer solar system than Venus," Asphaug said. "But actually, with Earth in this vanguard role, it makes it actually more likely for Venus to accrete outer solar system material."

Both new studies — the one led by Asphaug and the one led by Emsenhuber — were published online Thursday (Sept. 24) in The Planetary Science Journal.


Mike Wall is the author of "Out There" (Grand Central Publishing, 2018; illustrated by Karl Tate), a book about the search for alien life. Follow him on Twitter @michaeldwall. Follow us on Twitter @Spacedotcom or Facebook.