Earth Hottest It's Been in 400 Years or More, Report Says

Courtsey: http://news.nationalgeographic.com/news/2006/06/060623-global-warming.html

The last two decades of the 20th century were the hottest in 400 years and quite likely the warmest for several millennia, a leading U.S. scientific body concludes in a new report.

The National Academies' National Research Council report also said "human activities are responsible for much of the recent warming."

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The U.S. Congress had requested the report after controversy arose last year over surface-temperature reconstructions published in the 1990s by climatologist Michael Mann, now at Pennsylvania State University, University Park, and colleagues.

The reconstructions resulted in the widely cited "hockey stick" graph, which shows Earth's temperature sharply rising in recent decades after a thousand years of stability. The graph looks like a hockey stick lying on its side.

To create the graph, Mann and his colleagues pulled together temperature evidence from specimens such as tree rings, corals, and cores of sediment and ice. They had to rely on this natural evidence because thermometer records go back only about 150 years.

The graph gained prominence when the United Nations published it in a 2001 report that concluded that greenhouse gases from human activities had probably caused most of the warming measured since 1950, according to the New York Times.

Critics of the graph have said that Mann and his colleagues based it on cherry-picked and erroneous data.

Gerald North is a geoscientist at Texas A&M University in College Station. He chaired the National Research Council panel that produced the new report, which was released yesterday.

At a press conference Thursday at the National Academies headquarters in Washington, D.C., North said Mann and his colleagues prepared their data in a professional manner.

"I certainly did not see anything inappropriate. I mean, there might have been things that maybe they could have done differently, better, but … I have no cause to think there was anything inappropriate," he said.

Coffin Nailed

Mann, in an interview with National Geographic News, said the new report "nailed the coffin on the skeptics."

"It's time for the public discussion to get beyond this silly debate about the hockey stick," he said.

"The main conclusion from the study in '99 has been recognized in multiple additional studies and multiple additional lines of evidence," Mann added.

The older study was first published in 1999 in the science journal Geophysical Research Letters.

Though scientists have documented global warming in several ways—melting Arctic ice, accelerating glaciers in Greenland, increasing concentrations of greenhouse gases—the hockey stick stands out for its visual summary of global warming.

A version of the graph appears in the Al Gore global warming movie, An Inconvenient Truth. (See "Al Gore's Inconvenient Truth Movie: Fact or Hype?")

Proxy Data

Tree rings, corals, and cores of sediment and ice are so-called proxy data. Scientists rely on them to estimate temperatures during time periods before humans began collecting records with instruments such as thermometers.

(See photos on measuring climate change.)

In the 1999 study Mann and colleagues concluded from the proxy data that the warming of the past few decades was unprecedented over the last 400 years and likely over the past thousand years.

However, he said, they were cautious about temperatures prior to 1600, as the data was incomplete.

The National Research Council echoes those findings in its new report, though it particularly emphasizes the shakiness of the data prior to 1600. The council called for more research to collect better data for the years prior to 1600.

The new report's authors conclude they have "a high level of confidence that the last few decades of the 20th century were warmer than any comparable period in the last 400 years … and potentially the last several millennia."

Congressperson Sherwood Boehlert, a New York Republican and chair of the U.S. House Committee on Science, requested the study in November after Representative Joe Barton, a Texas Republican, launched an investigation into Mann and his colleagues.

In a statement issued Thursday, Boehlert said, "There is nothing in this report that should raise any doubts about the broad scientific consensus on global climate change."

The Perils of Being Huge: Why Large Creatures Go Extinct

Once upon a time, a 2-ton wombat lumbered across the Australian Outback. Around the same time, mammoths and saber-toothed tigers had the California coastline all to themselves.

Millions of years before any of these animals existed, Tyrannosaurus rex and other colossal dinosaurs ruled the world.

These and some of the other largest and most fantastic creatures ever to walk the planet are long gone, victims of mass extinctions of large beasts. And for reasons poorly understood, often the animals to fill the voids were tiny by comparison.

Predisposed to extinction

Scientists generally accept that a giant asteroid slammed into the Gulf of Mexico some 65 million years ago, setting off a chain of catastrophic events that ultimately led to the extinction of dinosaurs. Whether or not an asteroid is to blame, the so-called KT boundary in the in fossil record displays a mass extinction of dinosaurs and other large animals around the world.

Small scavenging mammals and birds survived the event, and scientists can't say for sure why dinosaurs did not.

Since bigger beasts couldn't take shelter in small protected burrows, perhaps they were done in by fierce environmental conditions. Or maybe with so many plants dying off, big herbivores simply had nothing to eat, and as they died out, so did the big carnivores.

Or perhaps with all the stress, dinosaurs simply couldn't reproduce quickly enough to keep up with sexually nimble mammals and were soon outnumbered.

"If a disease or climate impact is severe enough to kill off most of the young in a generation, it will take a very long time to replace them," zoologist Alex Greenwood of Old Dominion University told LiveScience. "Smaller mammals like rodents, for example, would not be as severely affected since they have multiple young and a very short birth cycle."

Along with mammals, turtles and crocodiles, which can lay hundreds of eggs at a time, managed to survive the mass extinction. Also, because they could take shelter in water, these reptiles probably weren't competing with land mammals for resources.

A mammoth lesson

Then mammals got bigger. And eventually they paid the price.

Several mammoths and other big mammals died off during the Pleistocene/Holocene extinction event, which started around 50,000 years ago and continued through the end of the last major ice age about 10,000 years ago.

Today's large mammals— often with small populations, long gestation periods and late weaning ages—are similarly predisposed to sudden mass extinction, scientists say. For big beasts, taking care of offspring is typically a time sink and an energy drain, and the whole setup makes the young highly susceptible to predation.

Large mammals are also slow to reach sexual maturity, and mortality rates before that age are generally high. The slow pace at which new individuals are introduced to the population presents an obvious challenge to enduring tough times when population numbers drop precariously low.

Super predators

Mass extinctions occur with surprisingly regularity over the long haul. During the last 250 million years, there's been a big die-off roughly every 26 million years.

Adam Lipowski, a researcher at Adam Mickiewicz University in Poland, suggests the extinctions might sometimes be driven not by climate change or impacts from space, but by the emergence of super predators.

Big Stuff Dinosaurs That Learned to Fly Dinosaur Fossils Endangered and Threatened Wildlife

In 2005, Lipowski developed a computer simulation representing a population of many species competing for food and living space. Much of the time, "medium efficiency" predators prowled the virtual world and their numbers fluctuated only slightly in response to changes in prey population size.

But every so often, mutations would lead to the evolution of a super predator that quickly devours an entire prey population, which in turn leads to its own extinction.

The critters that survived the "predatory apocalypse" gradually mutated to fill new ecological niches, and the cycle began anew.

Look in the mirror

Humans could be considered today's super predators.

We've been implicated in the extinctions of mammoth, various saber tooth cats, and giant apes, as well as more recent extinctions of dodos, bonobos, and wild horses. Whether human hunting pressure, climate change or other factors were responsible remains controversial, however.

Meanwhile some whale species, among the biggest mammals that ever lived, have seen their populations drop to mere thousands in response to over-hunting and environmental pressures. Scientists estimate only about 300 North Atlantic right whales exist, with much of the attrition attributed to collisions with large shipping vessels and noisy ports causing navigational confusion.

Illegal poaching and habitat reduction have cut African elephant numbers in half, to 600,000, in the last 30 years. Scientists have determined that African lions'historic distribution has shrunk 82 percent in the last few decades and the wild population is estimated in only the low tens of thousands. And although Florida manatee numbers have nearly tripled in the last 15 years, the population hovers around just 3,000.

Humans can also initiate extinctions inadvertently.

Between 55,000 and 45,000 years ago, humans first set foot on Australia. At the time, large emu-like terrestrial birds and oversized wombats roamed the continent. But when humans started setting fires to clear land or flush prey from bushes, they also stripped the land of many of the plants the large animals favored.

Many of the smaller animals that adapted to eat the remaining plants survive today, while the two-ton wombat is no more.

Freak waves may be real cause of many sinkings

Freak ocean waves that rise to a height of 10-storey buildings may be sinking ships in accidents that are attributed to nothing more than poor weather.

Once dismissed as a nautical myth, freak or "rogue" waves have been recorded by shipping vessels and more accurately measured from oil and gas platforms at sea.

The waves arise by chance when others combine, leading to giant walls of water that momentarily tower above the rest of the ocean, at heights in excess of 30 metres. Research at Imperial College, London, shows that far from being rare events, rogue waves can emerge frequently, and may be responsible for some of the 200 supertankers and container ships longer than 200m that have sunk in poor weather conditions in the past two decades.

Chris Swan, who led the study, found that forecasts issued to warn shipping about the risks of rogue waves assume the choppiness of the sea varied little over the duration of a storm.

But he said that a combination of wave tank experiments and theoretical calculations revealed that in small patches of ocean, measuring up to a square kilometre, sea states vary enough to trigger rogue waves.

"We've shown that in a storm, if your ship or platform happens to be in the wrong place at the wrong time, it could experience much more severe wave conditions than you would expect from forecasts, including these freak waves that can cause enormous damage," said Professor Swan, whose study on freak waves appears in the journal, Proceedings of the Royal Society A.

According to Nigel Barltrop, professor of naval architecture at Strathclyde University, so little is known about many shipping accidents, that it can be difficult to know when a rogue wave is to blame.

"A lot of ships, when they go down, there's no real investigation possible without spending a lot of money, so most of them, no one really knows why they sink. These waves aren't like those you see on the beach, they are more like a solid wall of water."

Andrew Linington of the National Union of Marine, Aviation and Shipping Transport Officers, said: "We have to stop calling these freak or rogue waves because all the evidence seems to be suggesting they're to be expected with more frequency than people believed in the past.

"This kind of extreme weather is going to become more common with global warming. There's an urgent need to rewrite the rules of construction for all types of vessels.

"Our feeling is it's too easy to say an accident was a freak wave and right it off as that, but often when a ship falls victim to a wave, it'll be something as stupid as a porthole being broken and water flooding in that causes it to sink. Often, we're talking about bulk carriers and basically nobody cares.

"If these were passenger ships going down there'd be an outcry. There aren't many people in the industry taking it seriously."

Mysterious quasar casts doubt on black holes

• 18:21 27 July 2006
• NewScientist.com news service
• David Shiga

A controversial alternative to black hole theory has been bolstered by observations of an object in the distant universe, researchers say. If their interpretation is correct, it might mean black holes do not exist and are in fact bizarre and compact balls of plasma called MECOs.

Rudolph Schild of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts, US, led a team that observed a quasar situated 9 billion light years from Earth. A quasar is a very bright, compact object, whose radiation is usually thought to be generated by a giant black hole devouring its surrounding matter.

A rare cosmological coincidence allowed Schild and his colleagues to probe the structure of the quasar in much finer detail than is normally possible. Those details suggest that the central object is not a black hole. "The structure of the quasar is not at all what had been theorised," Schild told New Scientist.

A black hole, as traditionally understood, is an object with such a powerful gravitational field that even light is not fast enough to escape it. Anything that gets within a certain distance of the black hole's centre, called the event horizon, will be trapped.

A well accepted property of black holes is that they cannot sustain a magnetic field of their own. But observations of quasar Q0957+561 indicate that the object powering it does have a magnetic field, Schild's team says. For this reason, they believe that rather than a black hole, this quasar contains something called a magnetospheric eternally collapsing object (MECO). If so, it would be best evidence yet for such an object.

Flickering clues

The researchers used gravitational lensing to make their close observation of the quasar. This technique exploits rare coincidences that can occur when a galaxy sits directly between a distant object and observers on Earth.

The gravity of the intervening galaxy acts like a lens. As the intervening galaxy's individual stars pass in front of the quasar, this bending varies, making the quasar appear to flicker.

Carefully scrutinising this flickering allowed the researchers to probe fine details of the quasar's structure that are normally far too small to be resolved by even the most powerful telescopes.

Magnetic sweep

The researchers found that the disc of material surrounding the central object has a hole in it with a width of about 4000 Astronomical Units (1 AU is the distance between the Earth and the Sun). This gap suggests that material has been swept out by magnetic forces from the central object, the researchers say, and must therefore be a MECO, not a black hole.

"I believe this is the first evidence that the whole black hole paradigm is incorrect," says Darryl Leiter of the Marwood Astrophysics Research Center in Charottesville, Virginia, US, who co-authored the study. He says that where astronomers think they see black holes, they are actually looking at MECOs.

According to the MECO theory, objects in our universe can never actually collapse to form black holes. When an object gets very dense and hot, subatomic particles start popping in and out of existence inside it in huge numbers, producing copious amounts of radiation. Outward pressure from this radiation halts the collapse so the object remains a hot ball of plasma rather than becoming a black hole.

Extremely complex

But Chris Reynolds of the University of Maryland, in Baltimore, US, says the evidence for a MECO inside this quasar is not convincing. The apparent hole in the disc could be filled with very hot, tenuous gas, which would not radiate much and would be hard to see, he says. "Especially if you're looking with an optical telescope, which is how these observations were made, you wouldn't see that gas at all," he told New Scientist.

Leiter says this scenario would leave other things unexplained, however. The observations show that a small ring at the inner edge of the disc is glowing, which is a sign that it has been heated by a strong magnetic field, he says. In Reynolds's scenario, one would expect a much broader section of the disc to be heated, he says.

In any case, says Reynolds, it is difficult to draw conclusions from the team's detailed comparisons of their observations with models of black holes because those models are far from definitive. "We know the accretion of gas into black holes is an extremely complex phenomenon," he says. "We don’t know precisely what that would look like."

"It would be truly exciting if there was compelling evidence found for a non-black-hole object in these quasars," Reynolds adds. "I just don't think that this fits."

Journal reference: The Astronomical Journal (vol 132, p 420)

The girl who was raised by dogs

For five years, Oxana Malaya lived with dogs and survived on raw meat and scraps. When she was found she was running around on all fours barking. Elizabeth Grice hears her incredible story

She bounds along on all fours through long grass, panting towards water with her tongue hanging out. When she reaches the tap she paws at the ground with her forefeet, drinks noisily with her jaws wide and lets the water cascade over her head.

Up to this point, you think the girl could be acting - but the moment she shakes her head and neck free of droplets, exactly like a dog when it emerges from a swim, you get a creepy sense that this is something beyond imitation. Then, she barks.

The furious sound she makes is not like a human being pretending to be a dog. It is a proper, chilling, canine burst of aggression and it is coming from the mouth of a young woman, dressed in T-shirt and shorts.

This is 23-year-old Oxana Malaya reverting to behaviour she learnt as a young child when she was brought up by a pack of dogs on a rundown farm in the village of Novaya Blagoveschenka, in the Ukraine. When she showed her boyfriend what she once was and what she could still do - the barking, the whining, the four-footed running - he took fright. It was a party trick too far and the relationship ended.

Oxana is a feral child, one of only about 100 known in the world. The story goes that, when she was three, her indifferent, alcoholic parents left her outside one night and she crawled into a hovel where they kept dogs.

No one came to look for her or even seemed to notice she was gone, so she stayed where there was warmth and food - raw meat and scraps - forgetting what it was to be human, losing what toddler's language she had and learning to survive as a member of the pack.

A shameful five years later, a neighbour reported a child living with animals. When she was found, at the age of eight in 1991, Oxana could hardly speak and ran around on all fours barking, mimicking her carers.

Though she must have seen humans at a distance, and seems occasionally to have entered the family house like a stray, they were no longer her species: all meaningful life was contained in a kennel.

Judging from the complete lack of written documentation about her physical and psychological state when found, the authorities were not keen to record her case - neglect on this scale was too shameful to acknowledge - even though it has been of huge and continuing interest to psychologists who believe feral children can help resolve the nature-nurture debate.

What is known about "the Dog Girl" has been passed down aurally, through doctors and carers. "She was like a small animal. She walked on all fours. She ate like a dog," is about as scientific as it gets.

Last month, the British child psychologist and expert on feral children, Lyn Fry, went to the Ukraine with a Channel 4 film crew to meet Oxana, who now lives in a home for the mentally disabled.

Five years after a Discovery Channel programme about her, they wanted to see if she had integrated into community living. Fry was keen to find out how far the girl was still damaged - and to witness a reunion with her father.

"I expected someone much less human," says Fry, the first non-Ukrainian expert to meet Oxana. "I'd heard stories that she could fly off the handle, that she was very unco-operative, that she was socially inept, but she did everything I asked of her.

"Her language is odd. She speaks flatly as though it's an order. There is no cadence or rhythm or music to her speech, no inflection or tone. But she has a sense of humour. She likes to be the centre of attention, to make people laugh. Showing off is quite a surprising skill when you consider her background.

"She made a very striking impression on me. When I made her a gift of some wooden toy animals we had used in tests, she thanked me. Superficially, you would never know this was a young woman raised by dogs."

In the film, Oxana looks unco-ordinated and tomboyish. When she walks, you notice her strange stomping gait and swinging shoulders, the intermittent squint and misshapen teeth.

Like a dog with a bone, her first instinct is to hide anything she is given. She is only 5ft tall but when she fools about with her friends, pushing and shoving, there is a palpable air of menace and brute strength.

The oddest thing is how little attention she pays to her pet mongrel. "Sometimes, she pushed it away," says Fry. "She was much more orientated to people."

After a series of cognitive tests, Fry concluded that Oxana has the mental capacity of a six-year-old and a dangerously low boredom threshold. She can count but not add up. She cannot read or spell her name correctly

She has learning difficulties, but she is not autistic, as children brought up by animals are sometimes assumed to be. She is proud of her huge wristwatch with its many ringtones - but can't tell the time.

Experts agree that unless a child learns to speak by the age of five, the brain misses its window of opportunity to acquire language, a defining characteristic of being human.

Oxana was able to learn to talk again because she had some childish speech before she was abandoned. At an orphanage school, they taught her to walk upright, to eat with her hands and, crucially, to communicate like a human being.

The definition of a feral child (or "wild child") is one who, from a very young age, has lived in isolation from human contact, unaware of human social behaviour and unexposed to language.

The most famous was Victor of Aveyron (1797) portrayed in the 1969 film The Wild Child by François Truffaut. In the 1800s, there was the caged boy Kaspar Hauser (Herzog's The Enigma of Kaspar Hauser came out in 1974).

More recently, there was Genie, a girl who was kept in darkness for 13 years and discovered in California in 1970. Genie features alongside Oxana in the Channel 4 film as an example of gross neglect.

Through an interpreter, Oxana tells Fry that her mother and father "completely forgot about me". They argued and shouted. Her mother would hit her and she would pee herself in terror. She says she still goes off by herself into the woods when she is upset. You have to wonder which voice, animal or human, she uses when she gets there.

Although she knows it is socially unacceptable to bark, she certainly can, as the opening footage of the documentary Feral Children demonstrates. Lisa Plasco, executive producer, says: "She has been educated away from all those aspects of her past. But privately, I think she might [bark]. The sound level may have been enhanced in the film, but she certainly made those noises."

It was a similar show of canine behaviour that scared off her recent boyfriend. "To be confronted with what she was," says Fry, "put him off."

Oxana seems to be happy looking after cows at the Baraboy Clinic's insalubrious farm, outside Odessa. "It was dirty, terribly rundown and primitive," says Fry, "but in Ukrainian terms, very desirable.

Her carers are good people with the best interests of their charges at heart, though there is no therapy as such. Oxana is doing things she is good at."

It was here that the reunion with her father was staged a few weeks ago. Of her mother, whom Oxana has not seen since infancy, there is no trace. "We knew she very much wanted to meet him," says Plasco, "and we facilitated that but we didn't orchestrate it."

Fry was anxious about the way the meeting was conducted: Oxana standing alone as her estranged father and half-sister, Nina, whom she had never met, came slowly towards her, cameras rolling. A crowd of her friends, agog, watched the spectacle from a distance.

"I thought it was a good idea for them to meet but a very risky way of going about it. I felt anything could happen. It could have split them apart permanently. It was very tense. There needed to be someone beside her, holding her hand."

In the film, they stand awkwardly apart and it is ages before anyone speaks. Oxana breaks the silence. "Hello," she says. "I have come," replies her father.

The exchange is moving in its halting formality. "I thank you that you have come. I wanted you to see me milk the cows." Nina is the one who starts sobbing and Oxana puts her arm round her.

Oxana has a romantic notion of returning to live with her impoverished father, but it is doubtful whether that will happen. Fry's guess is that she will go for a holiday, see the reality of life there and return to the familiar.

Is Oxana capable of a life beyond the institution? Fry is doubtful. "She doesn't have the social or personal skills. She has had boyfriends but she doesn't have the ability to form long-term relationships or to understand give and take. She would rather fall out than compromise. She is a very vulnerable person and there is no protection for her outside that institution."

The Dog Girl will continue to be the subject of scientific scrutiny but the sad reality is that, although the amelioration of her terrible history has gone a long way, it can probably go no further.

Courtsey : http://www.telegraph.co.uk/arts/main.jhtml?xml=/arts/2006/07/17/ftdog17.xml&page=1

Sahara was once lush and populated
(Between periods of dryness were millennia of rainfall and lush vegetation)

At the end of the last Ice Age, the Sahara Desert was just as dry and uninviting as it is today. But sandwiched between two periods of extreme dryness were a few millennia of plentiful rainfall and lush vegetation.

During these few thousand years, prehistoric humans left the congested Nile Valley and established settlements around rain pools, green valleys, and rivers.

The ancient climate shift and its effects are detailed in the July 21 issue of the journal Science.


When the rains came
Some 12,000 years ago, the only place to live along the eastern Sahara Desert was the Nile Valley. Being so crowded, prime real estate in the Nile Valley was difficult to come by. Disputes over land often were settled with brutality, as evidenced by the cemetery of Jebel Sahaba where many of the buried individuals had died a violent death.

But around 10,500 years ago, a sudden burst of monsoon rains over the vast desert transformed the region into habitable land. This opened the door for humans to move into the area, researcher's found through 500 new radiocarbon dates of human and animal remains from more than 150 excavation sites. "The climate change at [10,500 years ago] which turned most of the [3.8 million square mile] large Sahara into a savannah-type environment happened within a few hundred years only, certainly within less than 500 years," said study team member Stefan Kroepelin of the University of Cologne in Germany.

Frolicking in pools
In the Egyptian Sahara, semi-arid conditions allowed for grasses and shrubs to grow, with some trees sprouting in valleys and near groundwater sources. The vegetation and small, episodic rain pools enticed animals well adapted to dry conditions, such as giraffes, to enter the area as well.
Humans also frolicked in the rain pools, as depicted in rock art from Southwest Egypt.
In the more southern Sudanese Sahara, lush vegetation, hearty trees, and permanent freshwater lakes persisted over millennia. There were even large rivers, such as the Wadi Howar, once the largest tributary to the Nile from the Sahara. "Wildlife included very demanding species such as elephants, rhinos, hippos, crocodiles, and more than 30 species of fish up to 2 meters (6 feet) big," Kroepelin told LiveScience.

A timeline of Sahara occupation:

22,000 to 10,500 years ago: The Sahara was devoid of any human occupation outside the Nile Valley and extended 250 miles further south than it does today.

10,500 to 9,000 years ago: Monsoon rains begin sweeping into the Sahara, transforming the region into a habitable area swiftly settled by Nile Valley dwellers.

9,000 to 7,300 years ago: Continued rains, vegetation growth, and animal migrations lead to well established human settlements, including the introduction of domesticated livestock such as sheep and goats.

7,300 to 5,500 years ago: Retreating monsoonal rains initiate desiccation in the Egyptian Sahara, prompting humans to move to remaining habitable niches in Sudanese Sahara.

The end of the rains and return of desert conditions throughout the Sahara after 5,500 coincides with population return to the Nile Valley and the beginning of pharaonic society.

New solar system discovered

Researchers claim to have discovered a new solar system that could host Earthlike planets.
Scientists from the University of Colorado, were running a computer simulations of four nearby solar systems that contained giant planets the size of Jupiter, the largest in our solar system.
They claim to have found an Earthlike planet that supposedly has the right conditions essential for supporting life.

The second solar system is likely to have a belt of rocky bodies the size of Mars or smaller, they said.

The other two do not have the proper conditions to form an Earth-size planet. Experts said that each system lay within 250 light years of Earth. Astronomers further said they had already found evidence that each system contained at least two giant planets the size of Jupiter, which had migrated close to their stars, perhaps as close as Mercury was to the Sun.

Sean Raymond from the University of Colorado said that for each of the four systems, they conducted 10 computerised simulations. They placed small planet embryos in the system to see if they were able to gather more material and form a true planet the size of Earth. Each simulation assumed the same conditions in the planetary system except that the position and mass of each protoplanet was altered slightly, he said in the research published in the June issue of the Astrophysical Journal.

"It's exciting that our models show a habitable planet, a planet with mass, temperature and water content similar to Earth's, could have formed in one of the first extrasolar multi-planet systems detected," said Rory Barnes, the co-author of the study.

Raymond said that even surprising was the fact that only systems that formed planets the size of Mars or smaller were stable. Earlier studies had shown that many known extrasolar planetary had regions stable enough to support planets ranging from the mass of Earth to that of Saturn.

"What surprised me the most was to see the system that only formed planets the size of Mars or smaller. Anything that grew too big would be unstable, so there was an accumulation of a lot of smaller protoplanets maybe one-tenth the size of Earth," he said.

“It was significant, that the models showed conditions could remain stable enough for 100 million years so that a planetary embryo would have a chance to gather more substance and develop into a body the size of the moon or Mars," said Nathan Kaib, from the University of Washington.

"In our early system, that's probably what our inner solar system looked like, with hundreds of bodies that size," he added.