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The Hypatia Stone is Older than the Solar System and Harder than a Diamond – Was it Expelled in a Type Ia Supernova Explosion?
This little stone, named Hypatia (after Hypatia of Alexandria, the first Western woman mathematician and astronomer), presents a tantalizing piece of an extraterrestrial puzzle that is getting ever more complex. According to Jan Kramers, of the University of Johannesburg in South Africa, “What we do know is that Hypatia was formed in a cold environment, probably at temperatures below that of liquid nitrogen on Earth. In our Solar System it would have been way further out than the asteroid belt between Mars and Jupiter, where most meteorites come from. Comets come mainly from the Kuiper Belt, beyond the orbit of Neptune and about 40 times as far away from the sun as we are. Some come from the Oort Cloud, even further out. We know very little about the chemical compositions of space objects out there.” (Image Credit: University of Johannesburg, Jan Kramers, et al.)
The Hypatia Stone is Older than the Solar System and Harder than a Diamond – Was it Expelled in a Type Ia Supernova Explosion?
In 2013 researchers announced that the Hypatia Stone found in the desert of south-west Egypt was definitely not from Earth. By 2015, other research teams found exotic micro-mineral compounds in the Hypatia Stone that are not known to occur on Earth, elsewhere in our Solar System, or in known meteorites or comets. So, what is the origin of this stone and could the minerals in it provide clues as to where it came from? Now, a new study by Jan Kramers, Georgy Belyanin, and Hartmut Winkler of the University of Johannesburg in South Africa and others indicates that the Hypatia Stone could be the first tangible evidence found on Earth of a Type Ia Supernova explosion. These rare supernovas are some of the most energetic events in the Universe and occur only once or twice per galaxy per century.
Micro-mineral analysis of the Hypatia Stone shows that its internal structure is somewhat like a fruitcake that has fallen off a shelf into some flour and cracked on impact, says Professor Kramers.
“We can think of the badly mixed dough of a fruit cake representing the bulk of the Hypatia pebble, what we called two mixed ‘matrices’ in geology terms. The cherries and nuts in the cake represent the mineral grains found in Hypatia ‘inclusions’. And the flour dusting the cracks of the fallen cake represent the ‘secondary materials’ we found in the fractures in Hypatia, which are from Earth,” he says.
The original extraterrestrial rock that fell to Earth must have been at least several meters in diameter, but disintegrated into small fragments of which the Hypatia Stone is one.
Straight away, the Hypatia mineral matrix (represented by fruitcake dough), looks nothing like that of any known meteorites, the rocks that fall from space onto Earth every now and then.
“If it were possible to grind up the entire planet Earth to dust in a huge mortar and pestle, we would get dust with on average a similar chemical composition as chondritic meteorites,” says Kramers. “In chondritic meteorites, we expect to see a small amount of carbon and a good amount of silicon. But Hypatia’s matrix has a massive amount of carbon and an unusually small amount of silicon.”
“Even more unusual, the matrix contains a high amount of very specific carbon compounds, called polyaromatic hydrocarbons, or PAH, a major component of interstellar dust, which existed even before our Solar System was formed. Interstellar dust is also found in comets and meteorites that have not been heated up for a prolonged period in their history,” adds Kramers.
In another twist, most (but not all) of the PAH in the Hypatia matrix has been transformed into diamonds smaller than one micrometer, which are thought to have been formed in the shock of impact with the Earth’s atmosphere or surface. These diamonds made Hypatia resistant to weathering so that it is preserved for analysis from the time it arrived on Earth.
Weirder grains never found before
When researcher Dr. Belyanin analyzed the mineral grains in the inclusions in Hypatia, (represented by the nuts and cherries of a fruitcake), a number of most surprising chemical elements showed up.
“The aluminum occurs in pure metallic form, on its own, not in a chemical compound with other elements. As a comparison, gold occurs in nuggets, but aluminum never does. This occurrence is extremely rare on Earth and the rest of our Solar System, as far as is known in science,” says Belyanin.
“We also found silver iodine phosphide and moissanite (silicon carbide) grains, again in highly unexpected forms. The grains are the first documented to be found in situ (as is) without having to first dissolve the surrounding rock with acid,” adds Belyanin. “There are also grains of a compound consisting of mainly nickel and phosphorus, with very little iron -- a mineral composition never observed before on Earth or in meteorites,” he adds.
Dr Marco Andreoli, a Research Fellow at the School of Geosciences at the University of the Witwatersrand in South Africa, and a member of the Hypatia research team says, “When Hypatia was first found to be extraterrestrial, it was a sensation, but these latest results are opening up even bigger questions about its origins.”
Unique minerals in our solar system
Taken together, the ancient unheated PAH carbon as well as the phosphides, the metallic aluminum, and the moissanite suggest that Hypatia is an assembly of unchanged pre-solar material. That means matter that existed in space before our Sun, the Earth, and the other planets in our solar system were formed.
Supporting the pre-solar concept is the weird composition of the nickel-phosphorus-iron grains found in the Hypatia inclusions. These three chemical elements are interesting because they belong to the subset of chemical elements heavier than carbon and nitrogen which form the bulk of all the rocky planets.
“In the grains within Hypatia the ratios of these three elements to each other are completely different from that calculated for the planet Earth or measured in known types of meteorites. As such these inclusions are unique within our Solar System,” adds Belyanin.
“We think the nickel-phosphorus-iron grains formed pre-solar, because they are inside the matrix, and are unlikely to have been modified by shock such as collision with the Earth’s atmosphere or surface, and also because their composition is so alien to our Solar System,” he adds.
A different kind of dust
Generally, science says that our Solar System’s planets ultimately formed from a huge, ancient cloud of interstellar dust (the solar nebula) in space. The first part of that process would be much like dust bunnies coagulating in an unswept room. Science also holds that the solar nebula was homogenous, that is, the same kind of dust everywhere.
But Hypatia’s chemistry tugs at this view. “For starters, there are no silicate minerals in Hypatia’s matrix, in contrast to chondritic meteorites (and planets like the Earth, Mars, and Venus), where silicates are dominant. Then there are the exotic mineral inclusions. If Hypatia itself is not pre-solar, both features indicate that the solar nebula wasn’t the same kind of dust everywhere – which starts tugging at the generally accepted view of the formation of our Solar System,” says Kramers.
A cosmic timeline
Since 2013, Belyanin and Kramers have discovered a series of highly unusual chemistry clues in a small fragment of the Hypatia Stone.
In the new research, they eliminate ‘cosmic suspects’ for the origin of the stone in a painstaking process. They have pieced together a timeline stretching back to the early stages of the formation of Earth, our Sun, and the other planets in our solar system.
Their hypothesis about Hypatia’s origin starts with a star: A red giant star collapsed into a white dwarf star. The collapse would have happened inside a gigantic dust cloud -- a nebula.
That white dwarf found itself in a binary system with a second star. The white dwarf star eventually ‘ate’ the other star. At some point, the ‘hungry’ white dwarf exploded as a Type Ia supernova inside the dust cloud.
After cooling, the gas atoms which remained from the supernova started sticking to the particles of the dust cloud.
“In a sense, we could say, we have ‘caught’ a supernova Ia explosion ‘in the act,’ because the gas atoms from the explosion were caught in the surrounding dust cloud, which eventually formed Hypatia’s parent body,” says Kramers.
A huge ‘bubble’ of this supernova dust-and-gas-atoms mix never interacted with other dust clouds.
Millions of years would pass, and eventually, the ‘bubble’ would slowly become solid, in a ‘cosmic dust bunny’ kind of way. Hypatia’s ‘parent body’ would become a solid rock sometime in the early stages of the formation of our Solar System.
This process probably happened in a cold, uneventful outer part of our Solar System – in the Oort cloud or in the Kuiper belt.
At some point, Hypatia’s parent rock started hurtling towards Earth. The heat of entry into the earth’s atmosphere, combined with the pressure of impact in the Great Sand Sea in south-western Egypt, created micro-diamonds and shattered the parent rock.
The Hypatia stone picked up in the desert must be one of many fragments of the original impactor.
“If this hypothesis is correct, the Hypatia stone would be the first tangible evidence on Earth of a supernova type Ia explosion. Perhaps equally important, it shows that an individual anomalous ‘parcel’ of dust from outer space could actually be incorporated in the solar nebula that our solar system was formed from, without being fully mixed in,” says Kramers.
“This goes against the conventional view that dust which our solar system was formed from, was thoroughly mixed.”
Three million volts for a tiny sample
To piece together the timeline of how Hypatia may have formed, the researchers used several techniques to analyze the strange stone.
In 2013, a study of the argon isotopes showed the rock was not formed on earth. It had to be extraterrestrial. A 2015 study of noble gases in the fragment indicated that it may not be from any known type of meteorite or comet.
In 2018 the UJ team published various analyses, which included the discovery of a mineral, nickel phosphide, not previously found in any object in our solar system.
At that stage, Hypatia was proving difficult to analyze further. The trace metals Kramers and Belyanin were looking for, couldn’t really be ‘seen in detail’ with the equipment they had. They needed a more powerful instrument that would not destroy the tiny sample.
Kramers started analyzing a dataset that Belyanin had created a few years before.
In 2015, Belyanin had done a series of analyses on a proton beam at the iThemba Labs in Somerset West, South Africa. At the time, Dr. Wojciech Przybylowicz kept the three-million Volt machine humming along.
In search of a pattern
“Rather than exploring all the incredible anomalies Hypatia presents, we wanted to explore if there is an underlying unity. We wanted to see if there is some kind of consistent chemical pattern in the stone” says Kramers.
Belyanin carefully selected 17 targets on the tiny sample for analysis. All were chosen to be well away from the earthly minerals that had formed in the cracks of the original rock after its impact in the desert.
“We identified 15 different elements in Hypatia with much greater precision and accuracy, with the proton microprobe. This gave us the chemical ‘ingredients’ we needed, so Jan could start the next process of analyzing all the data,” says Belyanin.
Proton beam also rules out Solar System
The first big new clue from the proton beam analyses was the surprisingly low level of silicon in the Hypatia stone targets. The silicon, along with chromium and manganese, were less than 1% to be expected for something formed within our inner solar system.
Further, high iron, high sulphur, high phosphorus, high copper, and high vanadium were conspicuous and anomalous, adds Kramers.
“We found a consistent pattern of trace element abundances that is completely different from anything in the solar system, primitive or evolved. Objects in the asteroid belt and meteors don’t match this either. So next we looked outside the solar system,” says Kramers.
Not from our neighborhood
Then Kramers compared the Hypatia element concentration pattern with what one would expect to see in the dust between stars in our solar arm of the Milky Way galaxy.
“We looked to see if the pattern we get from average interstellar dust in our arm of the Milky Way galaxy fits what we see in Hypatia. Again, there was no similarity at all,” adds Kramers.
At this point, the proton beam data had also ruled out four ‘suspects’ of where Hypatia could have formed.
Hypatia did not form on earth, was not part of any known type of comet or meteorite, did not form from average inner Solar System dust, and not from average interstellar dust either.
Not a red giant
The next simplest possible explanation for the element concentration pattern in Hypatia, would be a red giant star. Red giant stars are common in the universe.
But the proton beam data ruled out mass outflow from a red giant star too -- Hypatia had too much iron, too little silicon and too low concentrations of heavy elements heavier than iron.
Nor a Type II Supernova
The next ‘suspect’ to consider was a Type II Supernova. Supernovas of type II cook up a lot of iron. They are also a relatively common type of supernova.
Again, the proton beam data for Hypatia ruled out a promising suspect with ‘chemistry forensics.’ A Type II supernova was highly unlikely as the source of strange minerals like nickel phosphide in the pebble. There was also too much iron in Hypatia compared to silicon and calcium.
It was time to closely examine the predicted chemistry of one of the most dramatic explosions in the universe.
Heavy metal factory
A rarer kind of supernova also makes a lot of iron. Type Ia Supernovas only happen once or twice per galaxy per century. But they manufacture most of the iron in the universe. Most of the steel on earth was once the element iron created by Type Ia Supernovas.
Also, established science says that some Type Ia Supernovas leave very distinctive ‘forensic chemistry’ clues behind. This is because of the way some Type Ia Supernovas are set up.
First, a red giant star at the end of its life collapses into a very dense white dwarf star. White dwarf stars are usually incredibly stable for very long periods and most unlikely to explode. However, there are exceptions to this.
A white dwarf star could start ‘pulling’ matter off another star in a binary system. One can say the white dwarf star ‘eats up’ its companion star. Eventually the white dwarf gets so heavy, hot and unstable, it explodes in a Type Ia Supernova.
The nuclear fusion during the Type Ia Supernova explosion should create highly unusual element concentration patterns, accepted scientific theoretical models predict.
Also, the white dwarf star that explodes in a Type Ia supernova is not just blown to bits, but literally blown to atoms. The Type Ia supernova matter is delivered into space as gas atoms.
In an extensive literature search of star data and model results, the team could not identify any similar or better chemical fit for the Hypatia Stone than a specific set of Type Ia Supernova models.
Forensic elements evidence
“All supernova Ia data and theoretical models show much higher proportions of iron compared to silicon and calcium than supernova II models”, says Kramers.
“In this respect, the proton beam laboratory data on Hypatia fit to supernova Ia data and models.”
Altogether, eight of the 15 elements analyzed conform to the predicted ranges of proportions relative to iron. Those are the elements silicon, sulphur, calcium, titanium, vanadium, chromium, manganese, iron, and nickel.
Not all 15 of the analyzed elements in Hypatia fit the predictions though. In six of the 15 elements, proportions were between 10 and 100 times higher than the ranges predicted by theoretical models for Type Ia Supernovas. These are the elements aluminum, phosphorus, chlorine, potassium, copper, and zinc.
“Since a white dwarf star is formed from a dying red giant, Hypatia could have inherited these element proportions for the six elements from a red giant star. This phenomenon has been observed in white dwarf stars in other research,” adds Kramers.
If this hypothesis is correct, the Hypatia Stone would be the first tangible evidence on Earth of a Type Ia Supernova explosion -- one of the most energetic events in the universe.
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