Tag Archives: meteorite

Curiosity finds weird metallic meteorite on Mars

While taking its usual stroll on Mars, the Curiosity Rover found something unexpected: a dark, smooth meteorite. That in itself wouldn’t be too strange because meteorites are quite common on the Red Planet – due to its thin atmosphere and relative proximity to the asteroid belt. But this one was unusual.

NASA/JPL-Caltech/LANL/ASU

Based on its appearance, we can already say quite a lot about it. Its shape was what attracted the scientists. It’s unusually smooth, almost as if someone polished it. It also has two deep grooves — both things suggest that it melted almost completely at one point in its history. It seems to be made of iron-nickel, as are many objects in the asteroid belt.

The object was probably thrown out of the asteroid belt by Jupiter’s gravity at one point. As it hurdled towards Mars, it partially melt in the planet’s atmosphere, but still managed to reach the surface of the planet mostly intact – on Earth, this wouldn’t happen because our atmosphere is simply stronger and would completely disintegrate the rock. In fact, this is why astronomers and geologists are equally interested in studying Mars meteorites.

Not only is the atmosphere on Earth more likely to destroy meteorites, but even those which survive are much heavier oxidized, their chemistry altered by local processes. Mars, on the other hand, has much less oxidation and erosion, and meteorites on the Red Planet are much closer to their initial state and can, therefore, tell us more about the early stages of the solar system.

As for Curiosity, its valiant mission continues. The rover has already found evidence of flowing water and is now looking for evidence of habitability. Since it’s not really allowed to screen the water directly, it must look for evidence in rocks instead. Curiosity is currently roving around the base of Mount Sharp.

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Second largest meteorite in the world, a 30-tonne monster, unearthed in Argentina

meteorite-1

Credit: Astronomy Association of Chaco / Telam

A huge meteorite was excavated from Argentina’s famous Campo del Cielo, a well-known meteorite crash site. Estimates suggest the cosmic debris weighs more than 30 tonnes which ought to make it the second largest intact meteorite found so far.

The crater field of Campo del Ceilo, 1085km north of Buenos Aires, is comprised of at least 26 meteorite craters, created by impacts estimated to be 4,000-5,000 years old. The first record of the Campo dates from 1576 when the Spanish governor learned of some native indians who were dealing iron. When questioned, the indians said the iron fell from heaven and directed the Spanish authorities to the meteorite field. An expedition under the command of one Captain de Miraval reportedly brought back a few pieces of the iron-rich meteorites, among them a huge catch called the Meson de Fierro, which literally means large table of iron.

Oral indian tradition about the iron falling from the sky goes way back than the Spaniards. It could be that these tales are thousands of years old since the meteorites crashed in the Campo for the first time. Nevertheless, more than 100 tonnes have been excavated so far from the site blistered with craters.

Credit: Telam

Credit: Telam

The larger Campo del Cielo meteorites are found in and around a series of small craters in the southwestern part of the strewn field, where the largest crater is 78 by 65 meters. It was in one of these craters that a very large rock was excavated on September 10.

Though the meteorite needs to be properly weighed and assessed by scientists to find out things like its mineral composition and age, the find already looks like one destined for the history books.

The Hoba meteorite from Namibia. Credit: Public Domain

The Hoba meteorite from Namibia. Credit: Public Domain

The largest meteorite ever found — called Hoba — weighs more than 60 tonnes and was found in Namibia nearly a century ago by a farmer ploughing a field. You can still find it in the same location it fell more than 80,000 years ago. According to the Astronomy Association of Chaco, the newly uncovered meteorite is the second largest, despite El Chaco, the current runner-up discovered in 1967, weighing 37 tonnes.

It’s not clear yet if this new meteorite is the second largest in the world, but what’s for sure is Argentina now has two entries in the top three.

“We could compare the weight with the other large meteorite found in the province,” Mario Vesconi, the president of the Astronomical Association, to the Argentinian government’s news service, Télam. “Although we expected it to be heavier, we did not expect it to exceed 30 tons.”

“We will weigh it again,” Vesconi said. “Apart from wanting the added confidence of a double-check of the initial readings we took, the fact that its weight is such a surprise to us makes us want to recalibrate.”

AstroPicture of the Day: Moonless Meteors and the Milky Way

All APODs are spectacular in their own way – but every once in a while, there’s one that’s just amazing. This is the case with Petr Horálek‘s picture of the Perseids.

“The Perseid meteor shower last occurred near a New Moon in 2013. That’s when the exposures used to construct this image were made, under dark, moonless skies from Hvar Island off the coast of Croatia. The widefield composite includes 67 meteors streaming from the heroic constellation Perseus, the shower’s radiant, captured during 2013 August 8-14 against a background of faint zodiacal light and the Milky Way. The next moonless Perseid meteor shower will be in August 2018,” NASA writes.

Have geologists discovered all the big craters on Earth?

Mars has over 250,000 craters created by asteroid impacts, the Moon has millions – too many to count. But the Earth has an atmosphere, which means we’re protected against most threats and we have much to be thankful for. But even the craters that we do have are constantly eroded by wind and water, so finding and identifying them is quite a challenge. Just 128 confirmed large impact craters have been spotted on the Earth’s surface,an extremely low number. But a new study concluded that it’s not that we haven’t searched hard enough – those are simply all the craters that still exist on our planet’s surface.

The Meteor Crater is “only” 1 mile across – craters larger than this are becoming increasingly harder to discover… because we may have discovered them all.

It’s a surprising result.

“I’m definitely surprised.” says Brandon Johnson, a planetary scientist at the Massachusetts Institute of Technology in Cambridge, who was not involved in the study. “It’s the first time anyone has done this kind of thing—taking into account the effects of erosion.”

Stefan Hergarten and Thomas Kenkmann, geophysicists at the University of Freiburg in Germany have built their analysis on a previous study done by Johnson, who found that for craters 85 kilometers in diameter and larger, the geologic record is probably complete. But Hergarten and Kenkmann searched for craters that were “only” 6 kilometers across or more, and they came up with the same conclusion: we’ve simply found them all.

The result, as surprising as it seems, is somewhat satisfying.

“It tells us that it’s not just others being too stupid to find new craters,” he says.

Also, on the other hand, it means that geologists should somewhat change their focus, and start looking for small craters. Jay Melosh, an impact crater expert at Purdue University in West Lafayette, Indiana says the results are consistent with his recent observations: diminishing returns of crater hunting.

“What the new paper does is give the crater hunters a lot of hope for smaller craters,” Melosh says.

However, there is an important mention to be made; on a geological scale, the Earth’s surface is no immobile – it moves both horizontally and vertically, and therefore things that were once on the surface (such as craters) may now be buried. This study focused only on craters on the surface, but there may be some big ones out there – they just may be buried.

The most famous one is actually the most famous crater of them all: Chicxulub, in Mexico, the remnant of the asteroid that wiped off the dinosaurs. So if you want to find craters, Johnson has a good tip for you:

“Don’t stop searching,” he says, “just search deeper.”

Meteorites Not Responsible For Building Solar System, Study Finds

For decades, astronomers have believed that meteorites are the building blocks of our solar system – the lego blocks for planets. But a new study from scientists at MIT and Purdue University suggests that this may not be the case after all – and we’ve given meteorites too much credit.

meteorite

An artist’s rendering of a protoplanetary impact. Early in the impact, molten jetted material is ejected at a high velocity and breaks up to form chondrules, the millimeter-scale, formerly molten droplets found in most meteorites. These droplets cool and solidify over hours to days.
Credit: NASA/California Institute of Technology

Meteorites are solid pieces of debris  asteroids or comets, that originate in outer space and survive the impact with the Earth’s surface. The name meteorite is typically used when the object enters Earth’s atmosphere and survives the fall and the crash to the Earth’s surface. If it doesn’t enter our planet’s atmosphere, the strictly correct term is meteoroid.This new study, based on computer simulations, concluded that there’s no way meteorites could have been the building blocks of planets. Instead, the research concluded that meteorites are just debris resulting from proto-planetary collisions during the early days of the Solar System. If this is true, then studying meteorites won’t yield information about how the planets were like in their early stages, as was previously believed.

“This tells us that meteorites aren’t actually representative of the material that formed planets – they’re these smaller fractions of material that are the byproduct of planet formation,” says Brandon Johnson of MIT’s Earth, Atmospheric and Planetary Sciences department. “But it also tells us the early solar system was more violent than we expected: You had these massive sprays of molten material getting ejected out from these really big impacts. It’s an extreme process.”

Johnson and his colleagues, including Maria Zuber, the E.A. Griswold Professor of Geophysics and MIT’s vice president for research, have published their results this week in the journal Nature.

 

[Also Read: The Only Carving from a Meteorite]

Collision models indicate that astral bodies like our Moon (and others of similar sizes) likely formed way earlier than was previously believed, and way before chondrites formed. Chondrites are stony (non-metallic) meteorites that have not been modified due to melting or differentiation of the parent body.

“If this finding is correct, then it would suggest that chondrites are not good analogs for the building blocks of the Earth and other planets,” said University of Chicago Associate Professor of Planetary Science, Fred Ciesla. “Meteorites as a whole are still important clues about what processes occurred during the formation of the Solar System, but which ones are the best analogs for what the planets were made out of would change.”

If this finding is true, then we should reanalyze what we know about the early stages of the Solar System. Image via IOP.

If this is the case, then meteorites are in fact byproducts, and not building blocks, and we’ll have to revise what we think about the early stages of the solar system.

“Chondrules were long viewed as planetary building blocks,” Zuber notes. “It’s ironic that they now appear to be the remnants of early protoplanetary collisions.”

However, not all computer simulations are accurate, and this is going to need some confirmation before it is viewed as a fact, but it casts a big shadow over something which was regarded as a near certainty for the longest of time.

“This would be a major shift in how people think about our solar system,” says Ciesla, who did not contribute to the research. “If this finding is correct, then it would suggest that chondrites are not good analogs for the building blocks of the Earth and other planets. Meteorites as a whole are still important clues about what processes occurred during the formation of the Solar System, but which ones are the best analogs for what the planets were made out of would change.”

Journal Reference:

  1. Brandon C. Johnson, David A. Minton, H. J. Melosh & Maria T. Zuber. Impact jetting as the origin of chondrules. Nature, 2014 DOI: 10.1038/nature14105

 

The Woman who was struck by a meteorite

The Sylacauga meteorite fell on November 30, 1954, at 14:46 local time (18:46 UT) in Oak Grove, Alabama, near Sylacauga. However, the meteorite is often called the Hodges meteorite – because it struck Ann Hodges, who became the first person confirmed to be hit by a meteorite.

It was an afternoon like any other. Ann Hodges was just napping on the couch when the meteorite struck the ceiling, hit the radio and bounced back to hit her in the shoulder. She was lucky she wasn’t hit directly. Other than the huge bruise and a big scare, Ann remained unharmed. But the aftermath was anything but quiet.

Upon hearing the news, neighbors started flocking to her house, with many claiming that the meteorite was “sent by the Soviets” – it was the time of the Cold War. A government geologist was sent in by helicopter to inspect the object and eventually determined that it was a meteorite, and not a communist weapon. It was actually a chondritic meteorite, with high amounts of iron. The most abundant minerals are bronzite (an orthopyroxene), and olivine.

Then, the legal fight for the meteorite began. Both Ann and her husband as well as the landlord demanded ownership of the meteorite. Ann got it, but about one year after the event, when public interest had already faded. She could never find a suitable buyer, and stressing out due to all the public attention, she eventually donated it to the Alabama Museum of Natural History in 1956.

Ironically, even though Ann was able to get hold of the meteorite one year after the event, local farmer Julius McKinney came upon the second-largest fragment from the same meteorite the very next day. He immediately sold it to the Smithsonian Institute. The money was enough for him to buy a new house, a car, and some land. Unfortunately, Ann got all of the problems and none of the prizes.

She however is almost certainly not the only person ever struck by a meteorite. A manuscript published at Tortona, Italy, in 1677 tells of a Milanese friar who was killed by a meteorite and in 1992, a small meteorite fragment (3 g) hit a young Ugandan boy in Mbale, but it was slowed down by a tree and only scared the boy.

 

 

Skydiver nearly struck by meteor, catches it all on film

Anders Helstrup and several other members of Oslo Parachute Club were expecting a good time, and no major events when they went skydiving in Hedmark, Norway. They most certainly weren’t expecting a meteor swooping by past them.

This is the first time in history that a meteorite has been filmed in the air after its light goes out. Thankfully, no one was hurt, even though it was a little too close for comfort. Also, Helstrup had two cameras fixed to his helmet, which allowed him to see the meteor on film, even though he didn’t realize it at the moment.

“I got the feeling that there was something, but I didn’t register what was happening,” Helstrup explained to NRK.no.

Immediately after landing, he watched the film and saw the culprit: a meteor. The adventurers that they are, he and his friends organized a search party, but were unable to find the meteorite. Eventually, he contacted the Natural History Museum in Oslo.

“The film caused a sensation in the meteorite community. They seemed convinced that this was a meteorite, perhaps I was the one who was the most sceptical.”

meteorite

Suddenly, more people got involved, and some triangulated the possible positions of the meteorite and started looking for it. The area has now been limited to 100 x 100 meters, but that’s big enough, especially considering that people don’t exactly know how the meteor looks like.

Largest lunar impact ever recorded

A piece of rock traveling at at 61,000 km/h punched a crater 40 metres wide on the surface of the Moon, producing a flash that could be seen from Earth.

I feel like Hollywood can ruin your expectations when talking about huge meteoritic impacts – we’re dealing with a meteorite here that’s way smaller than a car, weighing 400 kg; its diameter is around 1 meter. But due to its very high speed (40,000 mph), the meteorite punched a significant crater, 40 meters across.

The impact energy was equivalent to 15 tonnes of TNT, crashing into the so-called Mare Nubium (“sea of clouds” ) – a lunar mare. For some reason, many other websites (the Guardian for example) claim that the meteorite “…ploughed into an ancient lava-filled basin…” – which could leave the impression that there are actually lava basins on the surface of the Moon – something which, of course, isn’t true. They probably mean solidified lava – which is something commonly known as … rock.

The event was recorded by Spanish telescopes as part of their MIDAS project (Moon Impacts Detection and Analysis System). Even though this event took place back in 2013, it was officially announced and described just now, in a paper published in the Monthly Notices of the Royal Astronomical Society. Astronomer Jose Madiedo, who leads the Midas project at the University of Huelva processed the crash on 11 September 2013.

“When I saw it on the screen I realised I had witnessed a rare and unusual event. It was really huge. I couldn’t imagine such a bright event,” he said. “We image a lot of impacts on the moon, but they’re caused by very small rocks. They can be the size of a nut, and just a few grammes, and go up to 1kg. But this event was really impressive and very rare,” he said.

The impact was approximately three times larger than the second largest one, observed by NASA last year.

Unlike the Earth, the Moon doesn’t have an atmosphere to help protect it against meteoritic impacts. A rock of this size would be pretty much harmless on Earth, because friction would almost completely destroy it, by the time it reaches Earth. Though parts of very resistant rock might survive the intense heat of entry and reach the ground as small meteorites, they pose no real threat for humans, astronomers explain. However, researchers can study this impact and learn more about threats to Earth.

“We are very close neighbours.What happens on the moon can also happen on the Earth,” he said. “This impact … shows that the rate of impacts on our planet for rocks of this size, around one metre in diameter, is about 10 times greater than we thought.”

145 million year old body of seawater found under Chesapeake Bay

  • Chesapeake Bay is one of the few oceanic impact craters on Earth
  • When the huge impact took place ~35 million years ago, it sealed the ancient oceanic water
  • The water has remained virtually unchanged since then

 

A new study published in Nature provides chemical, isotopic and physical evidence that groundwater found at about 1.5 km deep under the Chesapeake Bay is actually a 145 million year old remnant of the Cretaceous North Atlantic Sea.

Image credit: Sanford WE et al.

Image credit: Sanford WE et al.

Metaphorically speaking, the aquifer described is just like a very ancient fly trapped in amber – preserving the exact conditions of the time it was sealed; the water is two times more salty than modern saltwater, providing valuable information about Cretaceous salinity. The entire setting was created with the “help” of a massive comet or meteorite that struck the area, its impact basically creating Chesapeake Bay.

“Previous evidence for temperature and salinity levels of geologic-era oceans around the globe has been estimated indirectly from various types of evidence in deep sediment cores. In contrast, our study identifies ancient seawater that remains in place in its geologic setting, enabling us to provide a direct estimate of its age and salinity,” said lead author Dr Ward Sanford of U.S. Geological Survey.

Chesapeake Bay is one of only a few impact craters that have been identified and described in oceanic waters. It’s estimated that the impact took place some 35 million years ago, ejecting enormous quantities of debris and creating humongous tsunamis that probably reached as far as the Blue Ridge Mountains, over 150 km away. This study not only highlights an underground structure that can provide valuable information about the marine environment from the Cretaceous, but it also helped geologists better understand the Chesapeake Bay itself.

“This study gives us confidence that we are working directly with seawater that dates far back in Earth’s history,” said Jerad Bales, acting U.S. Geological Survey’s Associate Director for Water. “The study also has heightened our understanding of the geologic context of the Chesapeake Bay region as it relates to improving our understanding of hydrology in the region.”

So how exactly was the aquifer preserved? Well generally speaking, an aquifer is an underground layer of water-bearing permeable rock or unconsolidated materials (gravel, sand, or silt), trapped between impermeable rocks. You can think of is basically as a wet sponge in a horizontal bottle – the sponge is the permeable rocks holding water, the bottle is the layers of impermeable rock. When the big impact took place, it created such an impermeable layer, trapping the ancient water beneath it.

Researchers had a hunch that they might find something interesting there by drilling boreholes, but they had no idea just how interesting things would get.

Scientific Reference: Evidence for high salinity of Early Cretaceous sea water from the Chesapeake Bay crater. Ward E. Sanford, Michael W. Doughten, Tyler B. Coplen, Andrew G. Hunt & Thomas D. Bullen. Nature 503, 252–256  doi:10.1038/nature12714

A slice through a fragment of the meteorite shows numerous veins from a long-ago impact shock that weakened the original object. (Qing-zhu Yin/UC Davis photo)

Meteoroid that caused massive damage in Russia fully described

At the beginning of the year the most powerful meteoroid strike since the infamous Tunguska event took place in Russia, over Chelyabinsk. The meteor exploded many kilometers above ground, however the event released so much energy that it appeared much brighter than the sun and the ensuing shock wave caused billions of rubles worth of damage and sent over 1,200 people to hospitals in the Chelyabinsk Oblast area that day. Was this bad luck or were we actually fortunate nothing more damaging occurred? Well, it’s best if we consider this a wake-up call.

“If humanity does not want to go the way of the dinosaurs, we need to study an event like this in detail,” said Qing-zhu Yin, professor in the Department of Earth and Planetary Sciences at UC Davis.

Now, many months after the event an international team of scientists report their final findings. Apparently, the Chelyabinsk meteorite was made out of  “ordinary chondrite”, or the most common material such cosmic bodies are made of. It entered Earth’s atmosphere at a whooping velocity of 19 kilometers per second and eventually the 20-meter sized alien rock eventually exploded at 30 km altitude from the high stress energies it was subjected.

The explosion was equivalent to about 600 thousand tons of TNT, 150 times bigger than the 2012 Sutter’s Mill meteorite in California. Its brightness peaked at an altitude of 29.7 km (18.5 miles) and was so intense that it appeared brighter than the sun. In fact, there had been reports of people hospitalized for severe sunburns. As for the shock wave itself that actually caused 99% of the damage it traveled  90 kilometers (50 miles) on either side of the trajectory.

Meteor impact – a reality

A slice through a fragment of the meteorite shows numerous veins from a long-ago impact shock that weakened the original object. (Qing-zhu Yin/UC Davis photo)

A slice through a fragment of the meteorite shows numerous veins from a long-ago impact shock that weakened the original object. (Qing-zhu Yin/UC Davis photo)

At the moment of explosion, some three quarters of the meteoroid (a meteoroid is the rock still in space or air; a meteorite is the rock that impacts the ground) evaporated instantly. The rest (4,000 to 6,000 kilograms, or less than 0.05 percent of the original mass)were fragmented into tiny pieces and dispersed over a wide area – the biggest chunk weighed about 650 kilograms and was recovered from the bed of Lake Chebarkul.

Most of these facts so far have already been determined shortly following the meteoroid event, greatly thanks to a lot of footage citizen science provided. This analysis only serves to paint a more detailed picture. The study does however provide some valuable new insights. Following isotopic analysis, magnetic properties determination and X-ray computed tomography scanning of the meteorites, the researchers learned a great deal about the history of the rock.

According to their findings, the Chelyabinsk meteoroid was  4,452 million years old and most likely originated from the Flora asteroid family in the asteroid belt, but the chunk that hit the Chelyabinsk area was apparently not broken up in the asteroid belt itself. Interestingly enough, the rock wasn’t at its first collision event. Previously, the researchers estimate, the meteoroid  went through a significant shock event about 115 million years after the formation of the solar system 4,567 million years ago.

“Chelyabinsk serves as unique calibration point for high energy meteorite impact events for our future studies,” he said. Technology for early detection of these objects is needed, Yin said — such as the Large Synoptic Survey Telescope, currently being developed by an international team headed by UC Davis physics professor J. Anthony Tyson.

The team was led by Olga Popova of the Russian Academy of Sciences in Moscow, and by NASA Ames and SETI Institute meteor astronomer Peter Jenniskens, and included 57 other researchers from nine countries. The findings were reported in the journal Science.

Severed trees in the wake of the Tunguska alleged meteor impact. Photo circa 1908. (c) UNIVERSAL HISTORY ARCHIVE/GETTY IMAGES

Tunguska event was caused by meteor strike, rock sample analysis finds

You may have heard about the Tunguska event – a huge blast of energy which occurred in 1908 over Russia and flattened more than 2,000 square kilometres of forest. More than a century since, its remarkable that scientists have yet to confirm the source of what undoubtedly is the biggest Earth impact in recorded history. The leading theory is that a meteor exploding in the atmosphere caused the huge blast, however up until now this has been difficult to confirm despite being the likeliest option.

Severed trees in the wake of the Tunguska alleged meteor impact. Photo circa 1908. (c) UNIVERSAL HISTORY ARCHIVE/GETTY IMAGES

Severed trees in the wake of the Tunguska alleged meteor impact. Photo circa 1908. (c) UNIVERSAL HISTORY ARCHIVE/GETTY IMAGES

A recent study by scientists at the Institute of Geochemistry, Mineralogy and Ore Formation of the National Academy of Science of Ukraine in Kiev might settle the origin of the Tunguska event once and for all, after rock samples collected from a peat bog close to the epicentre of the blast bear uncanny physical characteristics found in other meteorites.

It’s quite curious how the source of such an important event, in which an equivalent energy of 3 to 5 megatonnes of TNT was discharged,  has been so difficult to confirm. In all likelihood, something that most geoscientists seem to agree upon, the even was triggered by a meteor impact, however some have proposed more extreme theories like antimatter and blackholes (yeah, blackholes…). This is because the impact was so powerful that no fragments could be retrieved.

Of course, the Soviets made a number of scientific expeditions in the area, but the best they could come up with were microscopic metallic spheres found in Tunguska soil samples, thought to be remnants of a vaporized meteorite, but these too are up for debate. Now, researchers in Ukrain led by Victor Kvasnytsya think they have finally sealed Tunguska.

In 1978  Mykola Kovalyukh, an Ukranian scientist, collected fragments of rocks, less than one millimeter wide, from the epicenter of the impact site. Subsequent research by Kovalykh at the time revealed that the fragments contained a form of carbon called lonsdaleite, which has a crystal structure somewhere between graphite and diamond, and forms under extreme heat and pressure. The grains also contained less of the dense metal iridium than is typically found in meteorites, so the scientific community concluded that Kovalykh’s samples weren’t actually from the meteor. Instead, what he had were terrestrial rocks altered by the high energy of the impact.

Luckily, technology has evolved a great deal since then, and after taking a second, more thorough look, Ukranian researchers found that Kovalykh may have actually been right. The scientists probed the sample samples using transmission electron microscopy and discovered carbon grains that were finely veined with iron-based minerals including troilite, schreibersite and the iron–nickel alloy taenite,  very similar to that in other iron-rich meteorites. “The samples have almost the entire set of characteristic minerals of diamond-bearing meteorites,” says Kvasnytsya.

Moreover, previous studies that modeled the impact found that an  iron-rich, stony asteroid was the only culprit that could have produced the effects reported on the ground, which conveniently fits the present findings.

Other researchers aren’t that convinced, however, citing inconclusive proof. The low levels of iridium and osmium in the samples are “a red flag” that raises doubts that the fragments originated in an asteroid, according to Phil Bland, a meteorite expert at Curtin University in Perth, Australia. Moreover, the peat sediment in which the samples were found has not been convincingly dated to 1908.

“We get a lot of meteorite material raining down on us all the time,” adds Bland. Without samples of adjacent peat layers for comparison, “it’s hard to be 100% sure that you’re not looking at that background”.

More tests by Kovalykh and his team, as well as those by other scientists, will be required to fully confirm the findings, which can be read in a paper published in the journal Planetary and Space Science

via Nature

Ancient Egyptians had alien jewelry

This ancient Egyptian trinket may not look like much, but it hides a very interesting story. Researchers have found that the 5,000-year-old iron bead is actually made from a meteorite.

egyptian bead

The nickel rich areas (blue) suggest its meteoritic origin.

The nickel rich areas (blue) suggest its meteoritic origin.

 

Archaeologists have found iron objects in ancient Egypt, dating them to 2-3 millennia BC. But the earliest evidence of smelting only appeared much later after that, so how could they obtain these objects?

The result, published on 20 May in Meteoritics & Planetary Science, not only details this spectacular object, but also explains how ancient Egyptians obtained iron millennia before the earliest evidence of iron smelting in the region, solving the long standing archaeological mystery. It could also suggest (though that’s still debatable) that they regarded meteorites highly as they developed their religion.

“The sky was very important to the ancient Egyptians,” says Joyce Tyldesley, an Egyptologist at the University of Manchester, UK, and a co-author of the paper. “Something that falls from the sky is going to be considered as a gift from the gods.”

Using microscopy and computed tomography, Diane Johnson, a meteorite scientist at the Open University in Milton Keynes, UK, and her colleagues analyzed the object. Microscopy alone showed that it has a content in nickel of over 30%, which alone suggests that it came from a meteorite. acking up this result, the team observed that the metal had a distinctive crystalline structure called a Widmanstätten pattern. Widmanstätten patterns, also called Thomson structures, are unique figures of long nickel-iron crystals found only in meteorites.

Widmanstätten pattern example.

Widmanstätten pattern example.

But they took things one step further – using computed tomography (CT scan), they found that the object was created by hammering a fragment of iron from the meteorite into a thin plate, then bending it into a tube. They then re-created a 3D model of the object.

So what does this mean for the entire Egyptian culture? The object is dated 3,300 BC, and the first signs of smelting occur almost 3 millennia after, in 600 BC. It is known that back then, iron was associated with royalty and even dinivity. So where do meteorites stand? Some archaeologists believe Egyptians thought of them as fragments from the gods, descending from the sky as gifts. But was this technique common, or was it nothing more than an accident?

Johnson says that she would love to check other iron artefacts, but it remains to be seen if museums will actually allow her to do so – hopefully, they will.

Reference: Nature doi:10.1038/nature.2013.13091

Hundreds of meteor sites have been recorded by NASA during the past few years alone. (c) NASA

Meteor crash on the moon causes biggest explosion since monitoring

In March, a medium sized meteorite slammed into the moon’s surface causing the greatest explosion observed thus far, ever since the moon’s surface was first monitored by NASA looking for such events eight years ago.  The meteorite collided with the moon at a mind-boggling 56,000 mph (90,000 kph), creating a new crater 65 feet wide (20 meters).

Unlike Earth, the moon doesn’t have a thick atmosphere to safeguard it from the never-ending cosmic onslaught. As such, it regularly gets hit by meteorites with as many as 300 collisions having been recorded thus far since NASA first launched its monitoring program. No impact, however, has been as powerful as a most recent one, when on March 17 a roughly 1-foot-wide (between 0.3 to 0.4 meters) meteorite , weighing 88 lbs (40 kg), slammed into the moon releasing an important amount of energy, as powerful as a 5 tons of TNT explosion.

Hundreds of meteor sites have been recorded by NASA during the past few years alone. (c) NASA

Hundreds of meteor sites have been recorded by NASA during the past few years alone. (c) NASA

The flash unleashed by the collision could have been seen with the naked eye by those fixing their gazes at the moon, according to NASA, though the event lasted for a mere second. Below, you can find embedded a NASA-produced 4 minute video reporting the meteorite crash, where you can also footage of the actual collision (skip to the 00:47 mark).

NASA scientists aren’t monitoring the lunar surface for meteor crashes just out of pure curiosity. The agency still has plans of sending astronauts or expensive equipment like rovers back on the moon – having a meteorite crashing right near the landing site or even in the vicinity of a manned outpost could spell disaster. By studying just how frequent meteorite crashes with the moon are and during which period, scientists can infer the safest spots and best timings for such maneuvers to be carried out.

Early asteroids in our solar system may have been giant mudballs, not rocks

There are millions of asteroids in our solar system. Be them the size of France or a small bus, these space rocks can be found through out the solar system, and have recently become the subject of entrepreneurial discussions, since even a single medium-sized asteroid is thought to carry trillions of dollars worth of rare materials, like platinum and rare earth minerals. While our current understanding of modern day asteroids is rather slim, that of ancient asteroids is even poorer and controversial.

Most of the asteroids in our solar system have been around of billions of years, but how were they shaped to their current form today and where did they come from? Phil Bland, a planetary scientist at Curtin University in Perth, Australia  is trying his best to fit at least a few bits of the giant puzzle together, and is keen on studying early asteroids.

Scientists are currently bewildered by seemingly contradictory formation models. For instance, meteorites – chunks of asteroids – that crashed into Earth show textural signs of water flowing through them. Chemical analysis however suggests that no water had flowed through them, since the chemical make-up is constant. So, the asteroid insides had and didn’t have at the same time water flowing through them. Quite the paradox, and while most theories consider ancient asteroids as being rock, Bland has taken a different approach – he believes these were initially mud-like, resembling more “cowpats” than rock.

asteroid ceres and cesta

Bland and colleagues first considered a couple of model primordial asteroids, 100 kilometers in diamater, made out of unconsolidated mixtures of coarse and fine particles, plus ice. Numerical simulations were ran and over the course of millions of years heat produced by the decay of radioactive elements began melting ice deeper inside the asteroid. Like a boiling pot of water, the ancient asteroid interior’s started churning with strong convective motions. This continued for millions of years, again, until the radioactivity decayed –  long enough to mix everything so thoroughly that the overall chemical make-up ends up constant, which would explain the paradox.

“If you say the system was melting and convecting because it was mud, then it becomes a more tractable problem,” says Steven Hauck, a planetary scientist at Case Western Reserve University in Cleveland, Ohio.

This is a highly difficult to prove theory, however. Bland hopes that once with the deployment of NASA’s Dawn mission in 2015 towards the largest asteroid in our solar system – the 1,000 kilometer wide Ceres asteroid – that evidence which might prove or disprove his simulations might surface.

The ancient mud-asteroid theory was presented in the journal Nature.

Extraterrestrial life found in meteorites? Uhm, probably not

Ok, so big news on the horizon: alien life forms have been found in a meteorite that recently crashed in Sri Lanka, on December 29, bringing along a new perspective on how we view the origin and movement of life. But… have they really?

diatoms2

Well, sorry to burst your bubble ladies and gentlemen, but in the words of the immortal Carl Sagan, great claims require great evidence, and this paper simply does not provide it. The first thing that popped to mind was the lead author: Chandra Wickramasinghe; not that there’s something special or negative about him or anything, but he actually submitted a similar paper earlier this year, in January. Just like that one, this one is lacking on several ends.

First of all, he doesn’t effectively prove that the samples are in fact from the claimed meteorite event – in fact, they don’t prove the samples are from meteorites at all; and most important of all, they can’t eliminate the risk of contamination. The samples were picked off the ground, and diatoms are everywhere on the ground. Even if the samples are from that particular meteorite, it took a few days before they were collected, and how are you gonna ensure that they weren’t contaminated? You pretty much can’t, at least not with the kind of test this team did.

diatoms1

Furthermore, no opinion of an outside expert is obtained; no information whatsoever from outside their own lab – this is not something you want to do when attempting a paradigm shift. That’s not to say that this is bad science – not at all. It provides a valuable input, but the paper is suggestive rather than conclusive. For example, one method they used to check if the sample is a meteorite was an oxygen isotope analysis. Basically, if you take a sample of rock from the Earth, and a sample from Mars, and a sample from an asteroid – you’ll get different oxygen isotope ratios. Wickramasinghe’s team did this analysis, and found the ratios from their sample differ from the Earth standard ratio, and then exclaimed:

“We conclude that the oxygen isotope data show [our samples] are unequivocally meteorites”.

Right? Wrong! Just think about carbonates – molecules very rich in oxygen that quickly form on a sample sitting on the ground. Carbonates will change the oxygen isotope ratio, and can make an ordinary rock look extraterrestrial. There are ways to get rid of carbonates before analyzing the sample, like say washing the samples in a solution of acetic or hydrochloric acid that dissolves them (standard procedure), but the team doesn’t mention such a process at all! Arguably, they conducted it and forgot to mention (despite the fact that prepping the samples is quite detailed in the paper), but even so, even if they did everything right, it still doesn’t show “unequivocally” that the samples are meteorites.

As a geologist, what strikes me the most is that they didn’t conduct a mineral analysis; this is the most basic, and perhaps the most relevant test you can make when trying to determine whether a rock is terrestrial or not. You take a very thin slice of it, look at it through a microscrope and figure out its geologic past – a trained eye will tell you in no more than a couple of hours if its terrestrial or not.

Contamination – I’m not even gonna go there. Not even a single control test for diatom contamination is not what you want to do.

So there you have it. There may very well be extraterrestrial diatoms that wondered on our planet via meteorite, but then again, just as likely, they may very well be contaminated, or the samples might just be terrestrial. No paradigm shift yet – not with this study.

Seas of molten and solidified rock on the Moon can be mistaken for pristine rocks

A new analysis of data from NASA’s Lunar Orbiter Laser Altimeter (LOLA) shows that molten rock created by lunar impacts has been around for much longer than previously believed.

moon melting

During its earliest days, the Moon was covered in an ocean of molten rock, pretty much like every planet out there. As that lunar magma ocean cooled over millions of years, a process called igneous differentiation took over. Basically, igneous differentiation is an umbrella term for the various processes by which magmas undergo bulk chemical change during the partial melting process (or cooling, emplacement or eruption).

However, according to Brown University researchers, this wasn’t the only time the lunar surface was melted on a massive scale. The Moon, unlike the Earth, has no atmosphere to protect it from meteorite impacts; these impacts are much more frequent and much more violent there. Such is the case with the impact event that formed the Orientale basin on the Moon’s western edge and far side: it produced a “sea” of lava some 350 km (220 miles) across, and almost 10 km (6 miles) deep. Similar processes happened at various times in the Moon’s history in at least 30 other large impact basins.

Microphogoraphs of lunar samples, as seen through cross polarized light.

Microphogoraphs of lunar samples, as seen through cross polarized light.

Vaughan and his colleagues show that as these melt seas cooled, they igneously differentiated in pretty much the same way it did during the Moon’s initial cooling phase, so rocks found there could actually be mistaken for pristine, original ones.

“This work adds the concept of impact melt magma seas to the lexicon of lunar rock-forming processes,” said planetary geologist James W. Head III, the Scherck Distinguished Professor of Geological Sciences and the senior researcher involved in the study. “It emphasizes that one must consider the detailed point of origin of the rocks in order to interpret them correctly.”

Bad thing is, these rocks include the ones brought back by the Apollo project and Russia’s Luna missions. It’s quite possible, the researchers say, that impact melt material is present in lunar samples thought to be representative of the early formation of the lunar crust, which if true, could raise some big question on previous interpretation. If lunar samples do include melt material, it would help to explain some puzzling findings from lunar samples.

The thing is, for differentiation to take place, it would have to remain liquid for several thousands of years, which is very likely, when you’re dealing with “seas” as big as the ones described here. The next question was what that differentiation might look like, and how can we determine the composition of the impact melt sea.

“This is a mechanism by which the Moon was later modified to add petrologic complexity,” Vaughan said. “It helps make sense of mineralogical data that doesn’t always fit in this lunar magma ocean idea.”

A man stands near a hole in the ice on Chebarkul Lake after a meteor strike. (c) AP

Origin of meteorite that shook Russia traced using amateur footage

Most of us likely own a phone  that has more computing power than that available for the entire Apollo mission which landed a man on the moon, still rather curiously we choose to dedicate most of it to browsing photos of cute cats on the web. Nevertheless, there comes a time when pedestrian technology can come to the aid of science, and recent events give to show how important citizen science can be.

Like most of you are aware by now, a few weeks ago while the world was trembling at the prospect of being hit by a giant asteroid, Russia had a giant fireball blazing through its skies. The meteorite exploded over the Ural mountains, causing millions of rubles in damage and injuring an estimate of 1000 people. The whole event was surprised in hundreds of instances by Russians who had the flair of quickly recording the fireball with their phones and digital cameras, along with CCTV, traffic and car-dashboard cameras.

A man stands near a hole in the ice on Chebarkul Lake after a meteor strike. (c)  AP

A man stands near a hole in the ice on Chebarkul Lake after a meteor strike. (c) AP

Most of these eventually ended up on the web, sending mixed emotions on the web as they went viral. However, since these videos captured the event from different angles, some with precise date and time stamps, scientists from Colombia  have been able to use these valuable amateur footage in conjunction with advanced trigonometry to establish the origin of the meteorite.

Based on the footage, along with impact sites like those at Lake Chebarkul, astronomers Lake Chebarkul Jorge Zuluaga and Ignacio Ferrin, from the University of Antioquia in Medellin determined the height, speed and position of the rock as it fell to Earth. To reconstruct the origin of the meteorite, however, the researchers employed a nifty trick. There’s a certain point during a meteorite’s atmospheric entry when it catches on fire, becoming bright enough to cast a noticeable shadow in the videos. This allowed them to establish six different properties of its trajectory through Earth’s atmosphere, data which they then inputted in an astronomy software to pinpoint its origin.

Apparently, the meteorite originated from the asteroid belt between Mars and Jupiter – known as the Apollo asteroids – that cross Earth’s orbit. The asteroid belt is home to the largest conglomeration of space rocks in our solar system as 5,200 of a total of  9,700 near-Earth asteroids discovered so far can be found here.

Concerning the meteorite itself, Popular Science reports it is a chondrite —the most common kind of space rock near Earth –  and spent 4.5 billion years in space undisturbed until it encountered out planet.

The Colombian scientists’ findings were reported in the journal Earth and Planetary Astrophysics.

2012 DA14 radar observation

NASA radar observation shows asteroid 2012 DA14 flyby [VIDEO]

I realize we’re maybe bugging some of you with these constant asteroid/meteor pieces here on ZME Science, but for what’s it worth we found this recently released NASA video comprised of radar images during 2012 DA14’s recent flyby very interesting.

2012 DA14 radar observationThe movie, which combines 73 radar-images  captured over the course of eight hours on the night of Feb. 15-16, was compiled by NASA’s Jet Propulsion Laboratory. Now, if you’ve already pressed play and seen the movie, you might have felt a bit disappointed. But even though the asteroid might look like something off of Space Invaders, the image resolution is still a whooping 13 feet (4 meters) per pixel.

That goes a bit to show how massive DA14 really is and how devastating an eventual collision of the asteroid with our planet might have caused. These radar observations provide the most accurate measurement of DA14,  40 meters along its long axis. Also, the radar imaging also help better fine-tune calculations of 2012 DA14’s future orbit by getting a better fix on its size, shape, rotation, surface features and surface roughness. Next time it comes by Earth again, we’ll be ready.

If you’re interested, we’ve also posted some live video footage of 2012 DA14 captured by optical cameras and telescopes.

meteor-map

A map of every meteor strike since 2300 BC

The recent historical flyby of 2012 D14 – the largest asteroid ever to pass this close to Earth in recorded space observational history –  as well as the modest in size, but monumental in punch meteorite that exploded over Russia caused an whole frenzy around them on the web.

meteor-map

Thing is, meteorites and asteroids have been flying by and colliding with Earth long before the internet was invented, to the surprise of some folks. Javier de la Torre, cofounder of geo software companies Vizzuality and CartoDB, showcases this idea perfectly with his interactive map of every meteor strike on Earth, those found at least, since 2300 BC.

Actual impact data collected from the Meteoritical Society was used and you can click on specific impact sites in order to see the size, location and year that the meteorite strike occurred. If you’re more interested to find out how the map was created, check out de la Torre’s  blog post on the subject.

Check out the map here.

As you can see, North America and Europe have been simply bombarded along the years more than every other area on Earth. However, that’s not to say that other regions of the world have been spared; simply put, not enough data was available.

This scanning transmission electron microscope image shows the Wassonite grain in dark contrast. (c) NASA

New mineral discovered in 4.5 billion year-old meteorite

Using 21st century nanotechnology, researchers have discovered a new mineral in samples from a meteorite discovered in Antarctica in 1969. The meteorite is 4.5 billion years old and originates from an asteroid orbiting between Mars and Jupiter.

This scanning transmission electron microscope image shows the Wassonite grain in dark contrast. (c) NASA

This scanning transmission electron microscope image shows the Wassonite grain in dark contrast. (c) NASA

The new mineral has alluded scientists for some time since its discovery by a Japanese expedition team to Antarctica more than half a century ago, maybe due to its extremely tiny size – less than one-hundredth as wide as a human hair. Luckily nanotech has advanced dramatically since the meteorite known as Yamato 691 was discovered – a very well known historical piece in meteorite research and one of the first nine such cosmic bodies discovered in the ice-fields of Antarctica in 1969.

NASA scientists and their co-researchers from Japan and South Korea discovered the mineral after they found some unknown inclusions on the surface of the meteorite. Upon analysis they found the new mineral is made up of sulfur and titanium molecules that form an intricate crystal lattice, and although the mineral is extremely tiny it represents an integral component of the meteorite’s chemical composition.

The mineral was named Wassonite, in honor of Prof. John Wasson (UCLA) known for his unrivaled achievements in meteorite research, and was recently approved by the International Mineralogical Association for addition in the official list of minerals.

This latest discovery goes to show just how many minerals are still unknown to scientists. So far more than 40,000 specimens of celestial materials including Martian and Lunar meteorites have been collected from Antarctica – expect many of these to yield untold secrets.

“More secrets of the universe can be revealed from these specimens using 21st century nano-technology,” said Nakamura-Messenger, once again emphasizing the pivotal role of the nano-technology equipment available at NASA facilities.