Metal Asteroid Psyche Might Have Had Volcanoes of Molten Iron

An artist's illustration of a metallic asteroid like Psyche. Image Credit: Elena Hartley/USC

Imagine a time in the Solar System’s past where the asteroids were not solid rock, but blobs of molten iron. It sounds strange, but that may have been the case. And in the right conditions, some of those asteroids would have sprouted volcanoes. One of those asteroids, Psyche, is the destination for a NASA mission.

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This Meteorite is One of the Few Remnants from a Lost Planet that was Destroyed Long Ago

What if our Solar System had another generation of planets that formed before, or alongside, the planets we have today? A new study published in Nature Communications on April 17th 2018 presents evidence that says that’s what happened. The first-generation planets, or planet, would have been destroyed during collisions in the earlier days of the Solar System and much of the debris swept up in the formation of new bodies.

This is not a new theory, but a new study brings new evidence to support it.

The evidence is in the form of a meteorite that crashed into Sudan’s Nubian Desert in 2008. The meteorite is known as 2008 TC3, or the Almahata Sitta meteorite. Inside the meteorite are tiny crystals called nanodiamonds that, according to this study, could only have formed in the high-pressure conditions within the growth of a planet. This contrasts previous thinking around these meteorites which suggests they formed as a result of powerful shockwaves created in collisions between parent bodies.

“We demonstrate that these large diamonds cannot be the result of a shock but rather of growth that has taken place within a planet.” – study co-author Philippe Gillet

Models of planetary formation show that terrestrial planets are formed by the accretion of smaller bodies into larger and larger bodies. Follow the process long enough, and you end up with planets like Earth. The smaller bodies that join together are typically between the size of the Moon and Mars. But evidence of these smaller bodies is hard to find.

One type of unique and rare meteorite, called a ureilite, could provide the evidence to back up the models, and that’s what fell to Earth in the Nubian Desert in 2008. Ureilites are thought to be the remnants of a lost planet that was formed in the first 10 million years of the Solar System, and then was destroyed in a collision.

Ureilites are different than other stony meteorites. They have a higher component of carbon than other meteorites, mostly in the form of the aforementioned nanodiamonds. Researchers from Switzerland, France and Germany examined the diamonds inside 2008 TC3 and determined that they probably formed in a small proto-planet about 4.55 billion years ago.

Philippe Gillet, one of the study’s co-authors, had this to say in an interview with Associated Press: “We demonstrate that these large diamonds cannot be the result of a shock but rather of growth that has taken place within a planet.”

According to the research presented in this paper, these nanodiamonds were formed under pressures of 200,000 bar (2.9 million psi). This means the mystery parent-planet would have to have been as big as Mercury, or even Mars.

The key to the study is the size of the nanodiamonds. The team’s results show the presence of diamond crystals as large as 100 micrometers. Though the nanodiamonds have since been segmented by a process called graphitization, the team is confident that these larger crystals are there. And they could only have been formed by static high-pressure growth in the interior of a planet. A collision shock wave couldn’t have done it.

This is what’s called a High-Angle Annular Dark-Field (HAADF) Scanning Transmission Electron Microscopy (STEM) image. The image on the left shows diamond segments with similar crystal orientations. The image on the right is a magnification of the green square area. The orange lines highlight the inclusion trails, which match between the diamond segments. But those same trails are absent from the intersecting graphite. Image: Farhang Nabiei, Philippe Gillet, et. al.

But the parent body of the ureilite meteorite in the study would have to have been subject to collisions, otherwise where is it? In the case of this meteorite, a collision and resulting shock wave still played a role.

The study goes on to say that a collision took place some time after the parent body’s formation. And this collision would have produced the shock wave that caused the graphitization of the nanodiamonds.

The key evidence is in what are called High-Angle Annular Dark-Field (HAADF) Scanning Transmission Electron Microscopy (STEM) images, as seen above. The image is two images in one, with the one on the right being a magnification of a part of the image on the left. On the left, dotted yellow lines indicate areas of diamond crystals separate from areas of graphite. On the right is a magnification of the green square.

The inclusion trails are what’s important here. On the right, the inclusion trails are highlighted with the orange lines. They clearly indicate inclusion lines that match between adjacent diamond segments. But the inclusion lines aren’t present in the intervening graphite. In the study, the researchers say this is “undeniable morphological evidence that the inclusions existed in diamond before these were broken into smaller pieces by graphitization.”

To summarize, this supports the idea that a small planet between the size of Mercury and Mars was formed in the first 10 million years of the Solar System. Inside that body, large nanodiamonds were formed by high-pressure growth. Eventually, that parent body was involved in a collision, which produced a shock wave. The shock wave then caused the graphitization of the nanodiamonds.

It’s an intriguing piece of evidence, and fits with what we know about the formation and evolution of our Solar System.

Sources:

Meteorite Confirms 2 Billion Years of Volcanic Activity on Mars

Color Mosaic of Olympus Mons on Mars

Mars is renowned for having the largest volcano in our Solar System, Olympus Mons. New research shows that Mars also has the most long-lived volcanoes. The study of a Martian meteorite confirms that volcanoes on Mars were active for 2 billion years or longer.

A lot of what we know about the volcanoes on Mars we’ve learned from Martian meteorites that have made it to Earth. The meteorite in this study was found in Algeria in 2012. Dubbed Northwest Africa 7635 (NWA 7635), this meteorite was actually seen travelling through Earth’s atmosphere in July 2011.

A sample from the meteorite Northwest Africa 7635. Image: Mohammed Hmani
A sample from the meteorite Northwest Africa 7635. Image: Mohammed Hmani

The lead author of this study is Tom Lapen, a Geology Professor at the University of Houston. He says that his findings provide new insights into the evolution of the Red Planet and the history of volcanic activity there. NWA 7635 was compared with 11 other Martian meteorites, of a type called shergottites. Analysis of their chemical composition reveals the length of time they spent in space, how long they’ve been on Earth, their age, and their volcanic source. All 12 of them are from the same volcanic source.

Mars has much weaker gravity than Earth, so when something large enough slams into the Martian surface, pieces of rock are ejected into space. Some of these rocks eventually cross Earth’s path and are captured by gravity. Most burn up, but some make it to the surface of our planet. In the case of NWA 7635 and the other meteorites, they were ejected from Mars about 1 million years ago.

“We see that they came from a similar volcanic source,” Lapen said. “Given that they also have the same ejection time, we can conclude that these come from the same location on Mars.”

Taken together, the meteorites give us a snapshot of one location of the Martian surface. The other meteorites range from 327 million to 600 million years old. But NWA 7635 was formed 2.4 billion years ago. This means that its source was one of the longest lived volcanoes in our entire Solar System.

This false color X-ray of NWA 7635 shows the meteorite’s mineralogy mineral textures. O, olivine; P, plagioclase (maskelynite); C, clinopyroxene (augite). Chemical compositions: Fe (purple), Mg (green), Ca (blue), Ti (magenta), and S (yellow). Purple colors in the mesostasis represent Fe-rich augite. You’re welcome, mineral nerds. Image: Lapen et. al.

Volcanic activity on Mars is an important part of understanding the planet, and whether it ever harbored life. It’s possible that so-called super-volcanoes contributed to extinctions here on Earth. The same thing may have happened on Mars. Given the massive size of Olympus Mons, it could very well have been the Martian equivalent of a super-volcano.

The ESA’s Mars Express Orbiter sent back images of Olympus Mons that showed possible lava flows as recently as 2 million years ago. There are also lava flows on Mars that have a very small number of impact craters on them, indicating that they were formed recently. If that is the case, then it’s possible that Martian volcanoes will be visibly active again.

A colorized image of the surface of Mars taken by the Mars Reconnaissance Orbiter. The line of three volcanoes is the Tharsis Montes, with Olympus Mons to the northwest. Valles Marineris is to the east. Image: NASA/JPL-Caltech/ Arizona State University
A colorized image of the surface of Mars taken by the Mars Reconnaissance Orbiter. The line of three volcanoes is the Tharsis Montes, with Olympus Mons to the northwest. Valles Marineris is to the east. Image: NASA/JPL-Caltech/ Arizona State University

Continuing volcanic activity on Mars is highly speculative, with different researchers arguing for and against it. The relatively crater-free, smooth surfaces of some lava features on Mars could be explained by erosion, or even glaciation. In any case, if there is another eruption on Mars, we would have to be extremely lucky for one of our orbiters to see it.

But you never know.

Curiosity Finds a Melted Space Metal Meteorite on the Surface of Mars

Since it landed on the surface of the Red Planet in 2012, the Curiosity rover has made some rather surprising finds. In the past, this has included evidence that liquid water once filled the Gale Crater, the presence of methane and organic molecules today, curious sedimentary formations, and even a strange ball-shaped rock.

And most recently, Curiosity’s Mast Camera (Mastcam) captured images of what appeared to be a ball of melted metal. Known as “Egg Rock” (due to its odd, ovoid appearance) this object has been identified as a small meteorites, most likely composed of nickel and iron.

Egg Rock was first noticed in an image that was snapped by Curiosity on Oct. 28th, 2016, (or Sol 153, the 153rd day of Curiosity’s mission). The rover then snapped a two-frame portrait of the meteorite (seen below) two days later (on Sol 155) and studied it using its ChemCam’s Remote Micro-Imager (RMI). This provided not only a close-up of the strange object, but also a chance for chemical analysis.

Close up of Egg Rock, showing the laser reflection from Curiosity's ChemCam.  Credit: NASA/JPL
Close up of “Egg Rock”, showing the laser reflections from Curiosity’s ChemCam instrument. Credit: NASA/JPL

The chemical analysis revealed that the rock was composed of metal, which explained its melted appearance. In essence, it is likely the rock became molten as it entered Mars’ atmosphere, leading to the metal softening and flowing. Once it reached the surface, it cooled to the point that this appearance became frozen on its face.

Such a find is quite exciting, if not entirely unexpected. In the past, Curiosity and other rovers has spotted the remains of other metallic meteorites. For instance, back in 2005, the Opportunity rover spotted a pitted, basketball-sized iron meteorite that was named “Heat Shield Rock“.

This was followed in 2009 by the discovery of “Block Island“, a large dark rock that measured 0.6 meters (2 feet) across and contained large traces of iron. And in 2014, Curiosity spotted the mostly-iron meteorite that came to be known as “Lebanon” which measured 2 meters (6.5 feet) wide – making it the largest meteorite to ever be found on Mars.

However, “Egg Rock” is somewhat unique, in that its appearance seems more “melted” than meteorites spotted in the past. And as George Dvorsky of Gizmodo indicated, other aspects of its appearance (such as the long hollows) could mean that it lost material, perhaps when it still molten (i.e. shortly after it reached the surface).

Iron Meteorite on Mars. Opportunity finds an iron meteorite on Mars, the first meteorite of any type ever identified on another planet. The pitted, basketball-size object is mostly made of iron and nickel. Opportunity used its panoramic camera to take the images used in this approximately true-color composite on the Sol 339 (Jan. 6, 2005). Credit: NASA/JPL/Cornell
Image of the iron meteorite fpund on Mars by the Opportunity rover on the Sol 339 (Jan. 6th, 2005). Credit: NASA/JPL/Cornell

And such finds are always interesting because they provide us with the opportunity to study chunks of the Solar System that might not survive the trip to Earth. Given its greater proximity to the Asteroid Belt, Mars is better situated to be periodically struck by objects that get kicked out of it by Jupiter’s gravity. In fact, it is theorized that this is how Mars got its moons, Phobos and Deimos.

In addition, meteorites are more likely to survive passing through Mars’ atmosphere, since it is only about 1% as dense as Earth’s. Last, but certainly not least, meteorites have been striking Earth and Mars for eons. But since Mars has had a dry, desiccated atmosphere for all of that time, meteorites that land on its surface are subject to less wind and water erosion.

As such, Martian meteorites are more likely to be intact and better preserved over the long haul. And studying them will give planetary scientists opportunities they may not enjoy here on Earth. Now if we could just transport some of these space rocks home for a more detailed analysis, we’d be in business! Perhaps that should be something for future missions to consider.

Further Reading: ASU – Red Planet Report

Exclusive Photos Of The Recently Found 30-Ton Argentine Meteorite

A gigantic piece of the famous Campo del Cielo meteorite fall that was found on September 10, 2016 has been un-earthed, and is now on display in Gancedo, Chaco, Argentina. Photographer Pelin Rodriguez shared some images with Universe Today that he took of the newly found behemoth during a recent “Celebration of the Meteorite.”

And in a surprise finding during a weigh-in of both the new Gancedo meteorite and another meteorite named el Chaco that what was thought to be the biggest meteorite from the Campo del Cielo site, the Gancedo meteorite may actually be bigger. El Chaco was originally billed as 37 tons, but a recent tip of the scales put el Chaco at only 28 tons. Rodriguez said both meteorites will be weighed again in order to verify the tonnage. If confirmed, that would make the Gancedo meteorite the second largest meteorite chunk in the world after the 66-ton Hoba meteorite discovered in Namibia, Africa.

A close-up view of the Gancedo meteorite shows colorful details of the 30-ton rock. Credit and copyright: Pelin Rodriguez.
A close-up view of the Gancedo meteorite shows colorful details of the 30-ton rock. Credit and copyright: Pelin Rodriguez.

Rodriguez said the Gancedo meteorite contains many colors ranging from red, yellow, green, white and different shades of brown.

Scientists estimate about 4,500 years ago, a 600 ton space rock entered Earth’s atmosphere and broke apart, sending a shower of metallic meteorites across a 1,350 square km region northwest of Buenos Aires. The region has at least 26 craters, with the largest crater being about 100 meters wide. The AstronoR group said that the Gancedo meteorite was buried only 3 meters deep.

Rodriguez is a member of the AstronoR astronomy group in Argentina that held a two-day astronomy outreach event at the Village of Gancedo, located 312 km from Resistencia, the capital city of Chaco.

The el Chaco meteorite on display. Credit and copyright: Pelin Rodriguez.
The el Chaco meteorite on display. Credit and copyright: Pelin Rodriguez.

The Gancedo meteorite will be on permanent display in the village of Gancedo, Chaco, Argentina. Credit and copyright: Pelin Rodriguez.
The Gancedo meteorite will be on permanent display in the village of Gancedo, Chaco, Argentina. Credit and copyright: Pelin Rodriguez.

Another close-up view of the Gancedo meteorite. Credit and copyright: Pelin Rodriguez.
Another close-up view of the Gancedo meteorite. Credit and copyright: Pelin Rodriguez.

Another view of the Gancedo meteorite. Credit and copyright: Pelin Rodriguez.
Another view of the Gancedo meteorite. Credit and copyright: Pelin Rodriguez.

The area where the Campo del Cielo or "field of the sky" meteorites are on display. Credit and copyright: Pelin Rodriguez.
The area where the Campo del Cielo or “field of the sky” meteorites are on display. Credit and copyright: Pelin Rodriguez.

Thanks to Pelin Rodriguez for sharing his images with Universe Today. You can see some additional photos and videos from the event on the AstronoR Facebook page.

30-Ton Chunk Of 4,500 Year-Old Meteorite Unearthed In Argentina

Holy iron meteorite, Batman! A gigantic 30-ton chunk of the famous Campo del Cielo meteorite fall has been found outside of a small town in Argentina. The Gancedo meteorite was found on September 10, 2016 by a team of meteorite hunters from the Astronomy Association of the Chaco. This is the second largest piece ever found in the Campo del Cielo region.

Gancedo is the name of the town and Chaco is the province in Argentina where the meteorite was found.

A 30-ton Campo del Cielo meteorite being extracted from the ground in Argentina. Credit:  Ministerio de Gobierno Facebook page.
A 30-ton Campo del Cielo meteorite being extracted from the ground in Argentina. Credit: Ministerio de Gobierno Facebook page.

Scientists estimate about 4,500 years ago, a 600 ton space rock entered Earth’s atmosphere and broke apart, sending a shower of metallic meteorites across a 1,350 square km region northwest of Buenos Aires. The region has at least 26 craters.

A spokesman from the Chaco Astronomy Association said they will have the meteorite re-weighed to verify its weight.

The Ministerio de Gobierno Facbook page shared images and a video of the extraction.

While some media outlets have reported this is the second largest meteorite ever found, it actually is only the second largest meteorite from the Campo del Cielo site. The largest meteorite found on Earth is the Hoba meteorite, discovered in Namibia, Africa and is estimated to weigh more than 132,000 pounds (66 tons), and the second largest is the El Chaco, also part of the Campo del Cielo meteorite fall, which weighs an estimated 37,000 kilograms (37 tons).

Meteorites from Campo del Cielo are widely available, but if you are interested in getting a piece, buy only from reputable dealers.

Campo del Cielo meteorites are described as a polycrystalline coarse octahedrite, the most common kind of nickel-iron meteorites.

Sources and further reading: Facebook, ABC News, Scientific American, Meteorite Market.

470 Million Year Old Meteorite Discovered In Swedish Quarry

Osterplana 65, the meteorite at the heart of a mystery. This meteorite is different than the thousands of other meteorites in collections around the world. Image: Birger Schmitz

470 million years ago, somewhere in our Solar System, there was an enormous collision between two asteroids. We know this because of the rain of meteorites that struck Earth at that time. But inside that rain of meteorites, which were all of the same type, there is a mystery: an oddball, different from the rest. And that oddball could tell us something about how rocks from space can change ecosystems, and allow species to thrive.

This oddball meteorite has a name: Osterplana 65. It’s a fossilized meteorite, and it was found in a limestone quarry in Sweden. Osterplana 65 fell to Earth some 470 mya, during the Ordovician period, and sank to the bottom of the ocean. There, it became sequestered in a bed of limestone, itself created by the sea-life of the time.

The Ordovician period is marked by a couple thing: a flourishing of life similar to the Cambrian period that preceded it, and a shower of meteors called the Ordovician meteor event. There is ample evidence of the Ordovician meteor event in the form of meteorites, and they all conform to similar chemistry and structure. So it’s long been understood that they all came from the same parent body.

The collision that caused this rain of meteorites had to have two components, two parent bodies, and Osterplana 65 is evidence that one of these parent bodies was different. In fact, Ost 65 represents a so far unknown type of meteorite.

The faint grey lines in this electron image of Ost 65 are called "shock deformation lamellae" and they are evidence that Ost 65 was the result of a collision. Image: B. Schmidt
The faint grey lines in this electron image of Ost 65 are called “shock deformation lamellae” and they are evidence that Ost 65 was the result of a collision. Image: B. Schmidt

The study that reported this finding was published in Nature on June 14 2016. As the text of the study says, “Although single random meteorites are possible, one has to consider that Öst 65 represents on the order of one per cent of the meteorites that have been found on the mid-Ordovician sea floor. “It goes on to say, “…Öst 65 may represent one of the dominant types of meteorites arriving on Earth 470 Myr ago.”

The discovery of a type of meteorite falling on Earth 470 mya, and no longer falling in our times, is important for a couple reasons. The asteroid that produced it is probably no longer around, and there is no other source for meteorites like Ost 65 today.

The fossil record of a type of meteorite no longer in existence may help us unravel the story of our Solar System. The asteroid belt itself is an ongoing evolution of collision and destruction. It seems reasonable that some types of asteroids that were present in the earlier Solar System are no longer present, and Ost 65 provides evidence that that is true, in at least one case.

Ost 65 shows us that the diversity in the population of meteorites was greater in the past than it is today. And Ost 65 only takes us back 470 mya. Was the population even more diverse even longer ago?

The Earth is largely a conglomeration of space rocks, and we know that there are no remnants of these Earthly building blocks in our collections of meteorites today. What Ost 65 helps prove is that the nature of space rock has changed over time, and the types of rock that came together to form Earth are no longer present in space.

Ost 65 was found in amongst about 100 other meteorites, which were all of the same type. It was found in the garbage dump part of the quarry. It’s presence is a blemish on the floor tiles that are cut at the quarry. Study co-author Birgen Schmitz told the BBC in an interview that “It used to be that they threw away the floor tiles that had ugly black dots in them. The very first fossil meteorite we found was in one of their dumps.”

According to Schmitz, he and his colleagues have asked the quarry to keep an eye out for these types of defects in rocks, in case more of them are fossilized meteorites.

Finding more fossilized meteorites could help answer another question that goes along with the discovery of Ost 65. Did the types and amounts of space rock falling to Earth at different times help shape the evolution of life on Earth? If Ost 65 was a dominant type of meteorite falling to Earth 470 mya, what effect did it have? There appear to be a confounding number of variables that have to be aligned in order for life to appear and flourish. A shower of minerals from space at the right time could very well be one of them.

Whether that question ever gets answered is anybody’s guess at this point. But Ost 65 does tell us one thing for certain. As the text of the study says, “Apparently there is potential to reconstruct important aspects of solar-system history by looking down in Earth’s sediments, in addition to looking up at the skies.”

Astronomy Cast Ep. 416: Fireballs from Space!

Every now and then we look up and see bright fiery balls falling from the sky. Don’t panic, these are just bolides. Sometimes they leave trails, sometimes they explode, and sometimes they survive all the way to the ground.

Visit the Astronomy Cast Page to subscribe to the audio podcast!

We record Astronomy Cast as a live Google+ Hangout on Air every Monday at 12:00 pm Pacific / 3:00 pm Eastern. You can watch here on Universe Today or from the Astronomy Cast Google+ page.