Diamond-studded meteorites came from the collision of a lost planet

When our solar system was in its infancy 4.5 billion years ago, a swarm of protoplanets swirled around the sun—some of which coalesced into larger and larger masses, while others were blasted to smithereens in a demolition derby of planetary proportions. Those collisions would have produced innumerable fragments of cosmic shrapnel, some of which orbited the sun as carbon-rich asteroids. Now, a new analysis of the remains of one such asteroid, which broke apart in our atmosphere and fell to Earth, bolsters the idea that they are, in fact, the remnants of one of our solar system’s lost planets—some of which may have been the size of Mercury, or larger.

The Almahata Sitta meteorites, a few hundred rock fragments that rained down on Sudan’s Nubian Desert in 2008, included a number of coarse-grained, carbon-rich fragments known as ureilites. Inside were tiny diamonds that likely measured up to 100 micrometers across when they originally formed. That’s at least 100 times larger than the nanodiamonds that form when planetary objects collide, and it’s far larger than diamonds that form by condensing from carbon vapor inside clouds of interplanetary gas and dust. Excluding those possibilities, a new study proposes that the diamonds in the Almahata Sitta meteorites grew deep inside a large protoplanet before it suffered the collision that turned it into cosmic shrapnel (artist’s concept, above).</s>These diamonds tell the tale of how our solar system was born, revealing there once was an additional planet that didn't make the cut.

A decade after asteroid 2008 TC3 exploded over the Nubian Desert in northern Sudan, leaving behind a collection of small meteorites that would later be known as Almahata Sitta, researchers are still uncovering puzzling new details about this remarkable space rock.

According to NASA, this asteroid-turned-meteor was the first one to ever be detected in space before penetrating our planet’s atmosphere. But it turns out the asteroid is significant in more ways than one.

Although the asteroid’s composition didn’t remain a mystery for too long — the recovered 50 meteorites were quickly studied and identified as rare ureilites specked with tiny diamonds — little was known about where it had come from.

Now, for the first time in 10 years, a new study by scientists at the École Polytechnique Fédérale de Lausanne (EPFL) in Switzerland finally sheds some light into the asteroid’s planetary origin.

The paper, published in the journal Nature Communications, reveals that asteroid 2008 TC3 may have come from an ancient planet, formed early on during the birth of the solar system, reports the Washington Post.

The Swiss institute called it a planetary “embryo” — a proto-planet that was created in the early chaotic days when the solar system was just starting out, and that got torn apart by cosmic collisions some 4.5 billion years ago.

“There are many meteorites coming from Mars or the moon. However, this specific proto-planet has been destroyed in the early solar system and that is unique so far,” said lead researcher Dr. Farhang Nabiei of EPFL’s Earth and Planetary Science Laboratory.

His team reached this conclusion by examining the tiny diamonds found in the Almahata Sitta meteorites to determined their composition.

Using an advanced technology called transmission electron microscopy the scientists scanned some of the larger diamonds, which are only 100-microns wide — about the size of a human hair, notes Popular Science.

“The analysis of the data showed that the diamonds had chromite, phosphate, and iron-nickel sulfides embedded in them – what scientists refer to as ‘inclusions’,” EPFL explained in a news release.

These are the same elements that diamonds found on Earth are typically made of. The novelty, however, is that they’ve never been documented “in an extraterrestrial body” before, shows the Swiss institute.

Since the tiny diamonds found in the Almahata Sitta meteorites have a similar composition to the ones here on Earth, the logical explanation of how they came to be is that they were fashioned in the same — by “the ‘normal’ static pressure inside the parent body,” notes the EPFL.

Judging by the materials’ shape and content, the diamonds encrusted in Almahata Sitta meteorites were formed under extreme internal pressure, pressure higher than 20 giga-Pascals, explains the Swiss institute. That’s 197,385 times the pressure of Earth’s atmosphere at sea level, reports the Daily Mail.

This means that the parent body inside which they were formed (i.e. the ancient planet where 2008 TC3 came from) was bigger than Mercury and possibly even as large as Mars.

Therefore, the Almahata Sitta meteorites finally confirm the existence of large proto-planetary bodies, which had only been speculated until now.

“These samples are coming from an era that we don’t have any access to,” said lead researcher Dr. Farhang Nabiei of EPFL’s Earth and Planetary Science Laboratory.

Although small in size — the largest ones measuring less than four inches, shows The Meteoritical Society — the Almahata Sitta meteorites help unravel the mysteries of our solar system’s early days.</s>In 2008, an 80-ton asteroid entered the Earth’s atmosphere and exploded some 37 kilometers (23 miles) above Sudan’s Nubian Desert. It was estimated that the asteroid was around 4 meters (13 feet) in diameter when it hit our atmosphere and exploded into 600 smaller meteorites. These fragments only weighed around 10 kilograms (23 lb) altogether, but contained scores of tiny nanodiamonds which formed on impact with the atmosphere.

The asteroid’s official name is 2008 TC3, although it was later named Almahata Sitta. The impact marked the first time that meteorites were recovered from an asteroid which was tracked by astronomers prior to a collision with our planet. Researchers from the University of Khartoum in Sudan recovered many of the meteorites and nanodiamonds, providing an unprecedented glimpse into the life of asteroids and resulting meteorites. Scientists studying those nanodiamonds have just published the first study of these diamonds, and it turns out they might reveal a whole lot more than just the geological composition of space rocks. In fact, they might be evidence of an entire lost planet of our Solar System.

The research has been published in Nature. According to the article, this study marks “the first compelling evidence for such a large body that has since disappeared.” The authors note that due to the immense pressure required to form the types of nanodiamonds found in the Almahata Sitta meteorite, they were likely the result of an early planet in our solar system which is no longer in existence:

These diamonds contain inclusions that can only form above ~20 GPa, which can only be attained in a large planetary body.This study provides convincing evidence that the [meteorite] parent body was one such large “lost” planet before it was destroyed by collisions.

Several recent astronomical studies have claimed that irregularities in the orbits of our solar system’s planets and the anomalous tilt of the Sun could only be due to the existence of a hidden “Planet X.” Could these tiny diamonds prove such a planet actually used to exist? If so, what happened to it? Given the near-miss Earth just had with a sizeable, undetected asteroid, do we really want to know?</s>Fragments of a meteorite that fell to Earth more than a decade ago provide compelling evidence of a lost planet that once roamed our solar system, according to a study published Tuesday.

Researchers from Switzerland, France and Germany examined diamonds found inside the Almahata Sitta meteorite and concluded they were most likely formed by a proto-planet at least 4.55 billion years ago.

The diamonds in the meteorite, which crashed in Sudan’s Nubian Desert in October 2008, have tiny crystals inside them that would have required great pressure to form, said one of the study’s co-authors, Philippe Gillet.

“We demonstrate that these large diamonds cannot be the result of a shock but rather of growth that has taken place within a planet,” he told The Associated Press in a telephone interview from Switzerland.

Gillet, a planetary scientist at the Federal Institute of Technology in Lausanne, said researchers calculated a pressure of 200,000 bar (2.9 million psi) would be needed to form such diamonds, suggesting the mystery planet was as least as big as Mercury, possibly even Mars.

Scientists have long theorized that the early solar system once contained many more planets — some of which were likely little more than a mass of molten magma. One of these embryo planets — dubbed Theia — is believed to have slammed into a young Earth, ejecting a large amount of debris that later formed the moon.

“What we’re claiming here,” said Gillet, “is that we have in our hands a remnant of this first generation of planets that are missing today because they were destroyed or incorporated in a bigger planet.”

Addi Bischoff, a meteorite expert at the University of Muenster, Germany, said the methods used for the study were sound and the conclusion was plausible. But further evidence of sustained high pressure would be expected to be found in the minerals surrounding the diamonds, he said.

Bischoff wasn’t involved in the study, which was published in the journal Nature Communications.

Publication: Farhang Nabiei, et al., “A large planetary body inferred from diamond inclusions in a ureilite meteorite,” Nature Communications, volume 9, Article number: 1327 (2018) doi:10.1038/s41467-018-03808-6</s>An illustration of the early solar system, when the Almahata Sitta meteorite may have existed</s>A meteorite that crashed to Earth a decade ago was part of a long lost planet that formed in the early solar system, just a few million years after the birth of the sun.

The Almahata Sitta meteorite, which contains microscopic diamonds, come from a mysterious embryonic planet that once circled the sun 4.5 billion years ago, experts say.

The celestial body, which was slightly larger than Mercury, was destroyed in an epic cosmic collision.

As well as being extremely valuable, the rare diamonds provide scientists with a tantalising window into the formation of planets.

Tens of these budding worlds, which were generally between the size of the moon and Mars, smashed into each other to form the rocky planets we see today.

The Almahitta Sitta is named after the location in Sudan above which the space rock exploded in 2008.

Witnesses at the town of Wadi Halfa and at a railway stop in the Nubian desert, known as 'Station Six' or Almahata Sitta in Arabic, reported they had seen a 'rocket-like fireball' in the sky.

This extremely rare type of meteorite, known as an ureilite, is one of the main families of meteorites and range from few grams up to few kilograms.

The diamonds in the meteorite have tiny crystals inside them that would have required great pressure to form

The parent planetary body from which they formed is believed to have been catastrophically disrupted by an impact during the first 10 million years of the solar system.

'There are over 480 meteorites that are classified as ureilites,' lead researcher Dr Farhang Nabiei from the Swiss Federal Institute of Technology in Lausanne, told MailOnline.

'There are many meteorites coming from Mars or the moon. However, this specific proto-planet has been destroyed in the early solar system and that is unique so far.'

'Planetary formation simulations suggest that they were tens of planetary embryos in the size range between that of moon and that of Mars in the early solar system.'

The Swiss led team behind the find used a powerful scanning technique, called transmission electron microscopy.

They examined tiny crystals embedded within diamonds in the meteorite, to make the discovery.

The study showed the diamonds must have formed at pressures above 20 gigapascals, or 197,385 times the pressure of Earth's atmosphere at sea level.

This is equivalent to billions of tonnes of rock pushing down from above, crushing forces so high they must have happened on a Mercury to Mars-sized proto-planet.

Dr Nabiei added: 'Planetary formation models show terrestrial planets are formed by the accretion of tens of Moon- to Mars-sized planetary embryos through energetic giant impacts.

'However, relics of these large proto-planets are yet to be found.'

Nearly 50 fragments of the 83 tonne asteroid were collected from the desert in northern Sudan where it fell in October 2008.

The bus sized lump of rock was first detected by astronomers in the US and made headlines as it was tracked by telescopes around the world.

It eventually disintegrated in the atmosphere above the Nubian desert, posing no threat to human life.

Researchers studied a section of the Almahata Sitta ureilite where large diamonds were formed at high pressure inside their parent planet.

'We discovered chromite, phosphate, and sulfide inclusions embedded in the diamond', said Dr Nabiei.

'The composition and morphology of the inclusions can only be explained if the formation pressure was higher than 20 gigapascals.

'Such pressures suggest that the ureilite parent body was a Mercury- to Mars-sized planetary embryo.'

The researchers said these types of meteorites are the last remaining remnants of this lost planet.

An extensive ground search turned up 47 meteorite fragments for analysis.

The historic event - the first time such an object has been followed in this way - will boost our chances of avoiding a future catastrophe like the asteroid strike that wiped out the dinosaurs.

Almahitta Sitta was travelling at an estimated 27,739mph (44,642kph) until it disappeared in to the planet's shadow and was then observed as it exploded in a fireball as bright as a full moon.

Dr Nabiei said: 'Although this is the first compelling evidence for such a large body that has since disappeared, their existence in the early solar system has been predicted by planetary formation models.

'This study provides convincing evidence the ureilite parent body was one such large 'lost' planet before it was destroyed by collisions.'

The full findings were published in the journal Nature Communications.</s>Diamonds in a meteorite recovered from Sudan’s Nubian Desert have revealed traces of a lost planet, possibly as large as Mars, smashed to rubble early in the solar system’s history.

Planetary scientists have long believed the solar system once teemed with such bodies, which, during its chaotic infancy, either merged into larger planets, fell into the sun, were flung into interstellar space, or were dashed to bits by catastrophic collisions. But this is the first direct evidence that any such lost world truly existed.

The diamonds come from a meteorite called Almahata Sitta, which made headlines in 2008 when astronomers tracked a 4.1-metre asteroid into the Earth’s atmosphere and watched it explode in the skies above Sudan. Fragments collectively weighing about 10.5 kilograms were subsequently recovered and named for a railroad station between Khartoum and Wadi Halfa.

Almahata Sitta proved to be part of a family of meteorites called ureilites, of which several hundred are known. Scientists recreate ‘diamond rain’ of Uranus and Neptune in lab

“They are interesting meteorites, with strange properties,” says Farhang Nabiei, a materials scientist at École Polytechnique Fédérale de Lausanne, Switzerland.

Among other things, they include diamonds — enough to pose challenges to researchers.

“Ureilites are hard to cut and grind for thin sections because of the diamonds,” says Melinda Hutson, curator of the Cascadia Meteorite Laboratory at Portland State University in the US.

Nabiei and his team are the first to study these diamonds in detail.

Diamonds can be produced in space by a number of processes, but the ones in Almahata Sitta are too large to have been formed by most of them, Nabiei says.

They are not so large that thieves will be plundering them for gemstones. They are only 100 microns (0.1 millimetre) in size — barely large enough to be seen without a magnifying glass — and are badly cracked by subsequent events, such as impact shocks.

But they are large enough, Nabiei says, that they must originally have formed deep inside a protoplanet, just as Earth’s diamonds formed far below its the surface.

How deep can be determined by studying materials trapped within them.

To jewellers, such materials, dubbed “inclusions”, would be considered defects, but to planetary scientists they are the true gems. Nabiei calls them “direct samples” of the places where the diamonds formed.

Based on measurements of about 30 inclusions, he says, it appears that they could only have formed at pressures above 20 gigapascals (roughly 200,000 atmospheres).

“So the body should have been large enough to have had 20 gigapascals pressure inside its mantle,” Nabiei explains.

That means it must have been at least as large as Mercury, he says, which has a diameter of 4,900-kilometres, and possibly as big as Mars, with a 6,800 kilometre diameter. The difference depends on whether the Almahata Sitta diamonds formed all the way at the planet’s centre, or not quite as far down.

Hutson, who was not part of the study team, notes that Nabiei’s lost planet isn’t the only protoplanet that may have been destroyed in collisions.

Studies of a different class of meteorites, known as iron meteorites, she says, indicate that they may have been formed in protoplanets hundreds to thousands of kilometres across, “implying [other] large objects that have broken apart”. These, however, would not have been as large as the source of Nabiei’s diamonds.

Fragments of such bodies, she says, could have helped produce the large impact basins we see today on the moon, Mercury, Mars, and Jupiter’s moon Callisto. They may also have crashed into the Earth or Venus, where we can no longer see their imprint. And, she adds, “A lot of material could have been ground down to small pieces in [subsequent] collisions [and] ejected from the solar system by a number of processes that remove sand and dust-sized particles.”

The next step for Nabiei, whose work is published in the journal Nature Communications, is to look at more ureilites, seeking additional information about how their minerals formed — and from that, additional information about the lost world from which they originated.

For example, he says, these meteorites have some characteristics of materials that formed in the inner solar system, but they also contain large amounts of carbon, similar to things that formed in its outer regions.

“There are things we don’t understand,” he says, “and that’s where we learn.”</s>A new study suggests that diamonds found within a meteorite that landed on Earth in 2008 were created by an early lost planet in our solar system.

On Oct. 7, 2008, asteroid 2008 TC3, an 80-metric-ton rock measuring 4.1 metres in diameter, lit up the sky over the Nubian Desert in Sudan.

Although astronomers knew the rock — which belongs to the Almahata Sitta group of meteorites — didn't pose a danger to people, they were anxious to collect samples, hoping it could reveal more about the formation of our solar system.

By looking at the diamonds in asteroid 2008 TC3, the researchers hoped to find an answer about the origin of the meteorite.

Our early solar system was a chaotic shooting gallery. After the sun formed roughly 4.5 billion years ago, dust and debris collided and formed larger bodies. Astronomers believe that as many as 10 lost planets once existed.

"Some of [these bodies] collided and were destroyed. Some were thrown out of the solar system," Farhang Nabiei, lead author of the paper and a scientist with the Earth and Planetary Science Laboratory at the Ecole Polytechnique Federale de Lausanne in Switzerland, told CBC News.

"But we don't have information from them. We don't have much evidence from those specific planetary embryos."

That's what makes this latest discovery potentially exciting.

The key is in the diamonds

Almahata Sitta meteorites belong to an ancient group of asteroids called ureilites, which are rocks that have been melted and are rich in carbon. They contain graphite and tiny diamonds and are extremely strong, similar to what we may find in Earth's mantle.

Diamonds form in one of three ways: from a shockwave that transforms the mineral graphite into diamonds during a high-energy impact, such as the collision of objects; growth from carbon-rich gas vapour in the early solar nebula; or under extremely high pressure inside a body, like what occurs here on Earth.

In all cases, there must be a certain amount of pressure, measured in gigapascals. Using special electron microscopy, the scientists discovered the diamonds in asteroid 2008 TC3 formed under pressures exceeding 20 gigapascals, something that can only occur in a Mercury- to Mars-sized object from the embryonic solar system.

"We've often wondered, what is the parent body that formed this thing?" Peter Brown, professor at Western University's department of physics, who wasn't involved in the new study, told CBC News.

Now that question may have been answered.

"The particularly exciting thing is, [the researchers] have a really strong case with the pressures that they're measuring to say there really is no other way around the fact that this had to be a really big body present early in solar system history."

A better understanding of how the diamonds formed in an early planet helps scientists on a number of levels. Not only does it shed light on how our own planet formed — and how we came to be — but it could help us in the future, as companies consider asteroid mining.

"You're doing solar system geology," Brown said. "You're doing prospecting to tell you where you should go. The more we understand how these things formed, the better we're going to be in terms of going out and assessing where the resources are."

Ultimately, however, it's about putting the pieces of the puzzle together and getting a complete picture of our early solar system.

"We have to know more about our environment and how we've come to be," Nabiei said. "Everything started with the stars."</s>Ten years ago, an Arizona astronomer spotted an asteroid that was headed straight for Earth. Swiftly he summoned the help of colleagues and casual stargazers, who tracked the space rock as it exploded in the sky, raining shrapnel down on the Nubian desert in Sudan. Students from the University of Khartoum volunteered to search for fragments, ultimately recovering more than 600 pieces of the meteorite now known as Almahata Sitta. It was the first time scientists had ever traced an asteroid in the sky to a rock they could hold in their hands.

But that is not even the coolest thing about Almahata Sitta. Not nearly.

A new study published in the journal Nature Communications reports that the meteorite contains tiny diamonds – yes, diamonds. Those diamonds contain even tinier impurities called inclusions. And within those inclusions are signatures of a long-lost planet as large as Mars – a 4.5 billion-year-old relic that was destroyed during the earliest days of the solar system.

“These samples are coming from an era that we don’t have any access to,” said Farhang Nabiei, a materials scientist at the Swiss Federal Institute of Technology in Lausanne and the lead author of the new report. The diamonds with the Almahata Sitta meteorite formed during a transition era in the solar system, when the dust and gas that swirled around the sun coalesced into planetary embryos, then grew into planets.

“And we are part of the planets,” Nabiei said. “This is part of the story of how we came to be.”

Almahata Sitta belongs to a class of rocks known as ureilites. They are partly differentiated – not made of the primitive material that constituted the solar nebula, but also not as well mixed and baked as rocks that come from modern planets. Unlike other meteorites, which can be traced to parent bodies such as asteroids, Mars or the moon by comparing the ratios of different varieties of elements, these rocks have no known source. They seem to have been formed inside bodies that no longer exist.

And they always contain tiny flecks of diamond.

Because the crystals are so small – less than a fraction of a percentage of an inch in diameter – many researchers assumed that they formed when graphite (an alternate form of carbon) was “shocked” by a collision with another body. But Nabiei and his colleagues noticed that the diamonds in Almahata Sitta were orders of magnitude larger than the kind that result from a shock event. They suspected that these crystals may have formed the same way diamonds do on Earth – under the unbelievably high temperatures and pressures that exist in the interior of a planet – and only afterward were broken by a shock wave into smaller fragments.

“Then this opens whole new idea,” Nabiei said. Diamond is so strong it serves as a powerful protective packaging for anything trapped inside; it’s nature’s safety vault, capable of preserving samples for billions of years.

“I thought, if there were diamonds forming inside a planet, inside a parent body, they could have trapped some material from their environment,” Nabiei said. He laughed. “And indeed they did.”

The impurities trapped within the Almahata Sitta diamonds – crystals of chromite, phosphate and iron-nickel-sulfide – are the first to have been discovered in an extraterrestrial diamond. They could only have formed under incredible pressure – the equivalent of diving 600 kilometers into Earth’s interior or attempting to hold up 100,000 tons with your bare hands.

To create these conditions, Nabiei said, the meteorite’s parent body would have to have been a planet at least as big as Mercury and possibly as large as Mars.

Whatever happened to this lost world? Nabiei can’t say for sure. Many researchers believe that the early inner solar system was crowded with large protoplanets that yanked and tugged at each other’s orbits until they finally crashed, coalesced or disintegrated. By the end of that era, about 100 million years after the birth of the solar system, only the four current terrestrial planets remained.

Nabiei thinks it’s likely that all ureilites come from the same parent body, a protoplanet that lasted just a few million years before it was destroyed in a collision. He plans to seek out similar meteorites and search them for inclusions that might provide clues about their origins.</s>Shards of a lost planet from the early solar system may give us evidence of the chaos that surrounded the birth the terrestrial planets, including Earth. Researchers may have found the first relics of an enormous protoplanet that was smashed up into a type of meteorite we see today called a ureilite.

Most of the meteorites we have found on Earth are thought to be bits of asteroids that never grew to be planet sized. Now, Farhang Nabiei at the École Polytechnique …
New research suggests the Almahata Sitta meteorites are evidence of a lost additional planet in the Solar system.