Meteorite recovered in driveway in UK only days after landing

Meteorite hunters successfully recovered a meteorite only days after it plowed through the atmosphere and landed in a driveway in Gloucestershire in the United Kingdom on February 28th.

The fragment, weighing nearly 300 grams, and other pieces of the space rock were located after scientists reconstructed the flight path of the fireball that unleashed a sonic boom as it tore across the sky shortly before 10pm UK time on Sunday 28 February. The black chunk of rock, a carbonaceous chondrite never seen before in the UK, thumped on to a driveway in the Cotswolds town of Winchcombe, scientists at the Natural History Museum in London said, adding that further fragments were retrieved nearby.

Ashley Green, a scientist at the museum, said it was “a dream come true” to be one of the first people to see and study a meteorite that had been recovered almost immediately after coming down.

Footage of the bright streak captured by the public, and a camera network operated by the Natural History Museum’s UK Fireball Alliance, helped researchers calculate that the meteor had spent most of its orbit between Mars and Jupiter before it ploughed into Earth’s atmosphere.

I seriously doubt that no carbonaceous chondrite asteroids have never been found in Great Britain before. Instead, what the reporter misunderstood was that this was the first such asteroid in the UK recovered immediately after its arrival. Carbonaceous chondrites are very fragile. Much of their material will quickly erode and disappear, preventing researchers from obtaining a complete census of their entire make-up. Grabbing this thing mere days after landing means they will have a sample more closely resembling these kinds of asteroids in space.

In this way this rock is not much different than the samples being brought back from Hayabusa-2 and OSIRIS-REx. It isn’t as pristine, but it certainly carries far more information that meteorites recovered decades or even centuries after landing.

Similar quick recoveries in the past few years have forced some major rethinking about the make-up of the asteroid population. This meteorite will likely add to that revolution.

Meteorite stolen five years ago from Australian museum recovered

A meteorite that was stolen five years ago from a small Australian museum, only two weeks after it was donated to that museum, was recovered by police two days ago.

While the police have returned the meteorite, they have not yet revealed much else.

On Saturday, Queensland Police executed a search warrant at a Cairns address and recovered the space rock, valued at more than $16,000.

Investigations are underway into the incident, and no charges have been laid, but the sisters are pleased the meteorite is back in their possession.

…Police investigating the incident said they were looking into a number of leads relating to the theft. “I believe it definitely has a story to tell,” Senior Constable Heidi Marek said. “I’ll leave it up to detectives to uncover that story but hopefully we’re able to reveal a bit of information down the track.”

That no charges were file is most puzzling. I hope the full story is soon revealed.

The oldest known meteorite strike?

The uncertainty of science: Scientists think they have identified the oldest meteorite strike known on Earth, dated at 2.33 billion years ago, located in a known impact site in Yarrabubba, Western Australia.

Lead author Dr Timmons Erickson, from Curtin’s School of Earth and Planetary Sciences and NASA’s Johnson Space Center, together with a team including Professor Chris Kirkland, Associate Professor Nicholas Timms and Senior Research Fellow Dr Aaron Cavosie, all from Curtin’s School of Earth and Planetary Sciences, analysed the minerals zircon and monazite that were ‘shock recrystallized’ by the asteroid strike, at the base of the eroded crater to determine the exact age of Yarrabubba.

The team inferred that the impact may have occurred into an ice-covered landscape, vaporised a large volume of ice into the atmosphere, and produced a 70km diameter crater in the rocks beneath.

Professor Kirkland said the timing raised the possibility that the Earth’s oldest asteroid impact may have helped lift the planet out of a deep freeze. “Yarrabubba, which sits between Sandstone and Meekatharra in central WA, had been recognised as an impact structure for many years, but its age wasn’t well determined,” Professor Kirkland said. “Now we know the Yarrabubba crater was made right at the end of what’s commonly referred to as the early Snowball Earth – a time when the atmosphere and oceans were evolving and becoming more oxygenated and when rocks deposited on many continents recorded glacial conditions”.

Associate Professor Nicholas Timms noted the precise coincidence between the Yarrabubba impact and the disappearance of glacial deposits. “The age of the Yarrabubba impact matches the demise of a series of ancient glaciations. After the impact, glacial deposits are absent in the rock record for 400 million years. This twist of fate suggests that the large meteorite impact may have influenced global climate,” Associate Professor Timms said. [emphasis mine]

I truly believe they have determined the approximate age of this impact, making it one of the oldest known impacts. Implying however a “precise” linkage to other only vaguely known climate events, and inferring that the former was the cause of the latter seems to me to be a very large overstatement. Their data might suggest this conclusion, but the uncertainties here demand a bit less certitude..

Moon hit by small meteorite during eclipse

During the lunar eclipse two days ago on January 20, 2018 amateur astronomers were able to record the impact of a small meteorite.

The MIDAS survey is a Moon-watching that scours video of its surface in the hopes of detecting the tiny flashes associated with meteorite impacts. In this case, MIDAS scored a home run, and it was the first time the system was able to spot an impact during a total lunar eclipse.

“In total I spent almost two days without sleeping, including the monitoring time during the eclipse,” [Jose] Madiedo explained to Gizmodo. “I was exhausted when the eclipse ended—but when the automatic detection software notified me of a bright flash, I jumped out of my chair. It was a very exciting moment because I knew such a thing had never been recorded before.”

The meteorite itself wasn’t terribly large, and is estimated to have only been around 22 pounds.

I have embedded the video of the impact below the fold. It is very short, and the flash is not very impressive, but it still is quite cool.
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Scientists discover giant impact crater buried under Greenland ice

Scientists have discovered the existence of a giant impact crater buried under the Greenland ice.

An international team of researchers, including a NASA glaciologist, has discovered a large meteorite impact crater hiding beneath more than a half-mile of ice in northwest Greenland. The crater — the first of any size found under the Greenland ice sheet — is one of the 25 largest impact craters on Earth, measuring roughly 1,000 feet deep and more than 19 miles in diameter, an area slightly larger than that inside Washington’s Capital Beltway.

They think, based on the data, that this crater is very young, one of the youngest known on Earth. At the most is is no more than 3 million years old.

Sixth biggest Michigan meteorite discovered as doorstop

The sixth biggest Michigan meteorite ever discovered had been used as a doorstop for decades and was only identified when its present owner got curious and had it inspected by scientists.

Central Michigan University says Thursday that the 22.5-pound space rock was recently identified by Department of Earth and Atmospheric Sciences professor Dr. Monaliza Sirbescu after the owner “brought it to her out of curiosity.” The Grand Rapids man was apparently inspired to investigate after seeing news of meteorite hunters finding shards and selling them for thousands of dollars after a meteor sighting in January in the Detroit area.

The chunk of iron and nickel was later valued at $100,000 after the Smithsonian Institution verified the find, CMU said in a release. The rock, which was initially used as a doorstop in the Edmore area for several decades after a farmer recovered it sometime in the 1930s, turned out to be Michigan’s sixth-largest meteorite, a university spokesperson said.

Hat tip Wayne DeVette.

Largest Texas meteorite ever found by accident on dude ranch

The largest Texas meteorite ever, weighing 760 pounds, has been found on a Texas dude ranch.

The owner found it entirely by accident. It apparently had been there for a long time, but no one had noticed it, mostly because of its weathered appearance that made it appear much like any other boulder. Tests proved beyond doubt, however, that it was a meteorite, an L4 chrondite. It has now been sold to a meteorite collection at Texas Christian University in Ft. Worth.

Curiosity finds a meteorite

The Curiosity science team have identified and now analyzed a nickel-iron meteorite that Curiosity spotted on October 27.

Scientists of the Mars Science Laboratory (MSL) project, which operates the rover, first noticed the odd-looking rock in images taken by Curiosity’s Mast Camera (Mastcam) at at a site the rover reached by an Oct. 27 drive. “The dark, smooth and lustrous aspect of this target, and its sort of spherical shape attracted the attention of some MSL scientists when we received the Mastcam images at the new location,” said ChemCam team member Pierre-Yves Meslin, at the Research Institute in Astrophysics and Planetology (IRAP), of France’s National Center for Scientific Research (CNRS) and the University of Toulouse, France.

ChemCam found iron, nickel and phosphorus, plus lesser ingredients, in concentrations still being determined through analysis of the spectrum of light produced from dozens of laser pulses at nine spots on the object. The enrichment in both nickel and phosphorus at some of the same points suggests the presence of an iron-nickel-phosphide mineral that is rare except in iron-nickel meteorites, Meslin said.

The find is not unprecedented but it is interesting nonetheless.

Thirty ton meteorite excavated in Argentina

In what is one of the largest asteroid chunks ever found on Earth, an excavation team from a local astronomy club this week excavated a thirty ton iron-nickel meteorite from the ground.

Dubbed Gancedo after a nearby town, it isn’t a record-holder, but it sure is big. What I found interesting from the article, however, is this:

Gancedo’s fall to Earth occurred between 4,000 and 6,000 years ago. Locals knew of the fall for centuries, even making iron tools from meteorites found in the strewnfield. In the 16th century, the Spanish became interested in stories of a piece of iron that fell from the sky, and in 1774 don Bartolomé Francsico de Maguna led an expedition that came across a mass of iron, referred to as Mesón de Fierro (“Table of Iron” in Spanish). Another 1,400-pound fragment from Campo del Cielo named Otumpa now resides at the British Museum in London. With more than 100 tons of meteorite recovered, Campo del Cielo is the top producer in terms of pure meteorite mass worldwide.

The Campo del Cielo strewnfield extends over an ellipse 3 km wide by 19 km long over an area northwest of Buenos Aires, and meteorites found here have a polycrystalline coarse octahedrite composition characteristic of iron-nickel meteorites. They are also unusually pure even among iron-nickel meteorites, consisting of 93% iron. Most of the remaining 7% is nickel, and less than 1% are trace elements.

The evidence here is that a very dense asteroid, weighing a minimum of 100 tons but probably several times that, smashed into the Earth about five thousand years ago. Yet, all life on Earth was not wiped out, as is repeatedly suggested might happen whenever a similarly sized asteroid zips close past the Earth. In fact, there is no evidence this impact had any significant global environmental effects.

Remember this the next time another asteroid of similar size zips past the Earth and the media doom-sayers begin to sing their siren song again.

Rare large meteorite stolen from Australian museum

In a heist reminiscent of a Hollywood movie, two thieves in hooded jumpers and white masks stole a 25 pound meteorite the size of a soccer ball on Monday.

The only value of such a meteorite is among collectors, but to sell such a large and unique meteorite without being noticed would be impossible. It is theorized that the thieves might chop it up and sell the pieces to collectors instead.

Largest ancient meteorite impact found?

The uncertainty of science: Scientists doing geothermal research in Australia have discovered evidence of what they think is the largest known impact zone from an meteorite on Earth.

The zone is thought to be about 250 miles across, and suggests the bolide split in two pieces each about 6 miles across before impact. The uncertainty is that the evidence for this impact is quite tentative:

The exact date of the impacts remains unclear. The surrounding rocks are 300 to 600 million years old, but evidence of the type left by other meteorite strikes is lacking. For example, a large meteorite strike 66 million years ago sent up a plume of ash which is found as a layer of sediment in rocks around the world. The plume is thought to have led to the extinction of a large proportion of the life on the planet, including many dinosaur species.

However, a similar layer has not been found in sediments around 300 million years old, Dr Glikson said. “It’s a mystery – we can’t find an extinction event that matches these collisions. I have a suspicion the impact could be older than 300 million years,” he said.

In other words, they find some evidence that an impact occurred, but not other evidence that is expected to be found with such an impact. Moreover, the rocks at the sedimentary layer where the impact is found are dated around 300 million years ago, a time when no major extinction took place. Either this impact didn’t really happen, or it didn’t happen when it appears it should have, or it shows that large impacts don’t necessarily cause mass extinctions.

Organic material from Mars?

The uncertainty of science: Scientists theorize that the carbon material found in a 2011 meteorite could be Martian biological material.

Ejected from Mars after an asteroid crashed on its surface, the meteorite, named Tissint, fell on the Moroccan desert on July 18, 2011, in view of several eyewitnesses. Upon examination, the alien rock was found to have small fissures that were filled with carbon-containing matter. Several research teams have already shown that this component is organic in nature. But they are still debating where the carbon came from.

Chemical, microscopic and isotope analysis of the carbon material led the researchers to several possible explanations of its origin. They established characteristics that unequivocally excluded a terrestrial origin, and showed that the carbon content were deposited in the Tissint’s fissures before it left Mars.

Finding a meteorite 20 years after it hit the ground

By reanalyzing the data that had recorded the fireball twenty years ago, a team of meteorite hunters in the Czech Republic have finally located the remains of a meteorite that landed in 1991 but could not be found.

What is most interesting scientifically about their find is that the pieces they found were from different types of meteorites.

[T]hese four meteorites are of three different mineralogical types. This means that the Benešov meteoroid was heterogeneous and contained at least three different types of material. After the Almahata Sitta fall, this is the second time that such a heterogeneous composition has been found. It raises the possibility that a significant fraction of all asteroids are heterogeneous and that they were strongly reprocessed by collisions with other asteroids in the main belt.

In other words, the meteorite had been a conglomerate of different geological types, which were created in different environments and were later smashed together to form this one rock.

A skydiver’s helmet cam captures a meteorite zipping past him as it falls.

A skydiver’s helmet cam videotapes a meteorite zipping past him as it falls.

The incident happened back in the summer of 2012, when skydiver Anders Helstrup and other members of the Oslo Parachute Club took to the skies above Hedmark, Norway. Helstrup documented the jump with two cameras fixed to the front and back of his helmet. Helstrup tells NRK (the largest media outlet in Norway) that on the way down he felt “something” happen, but didn’t know what. It was only after landing and reviewing his camera footage that he discovered something shocking: a rock had fallen from the heavens and missed him by just a few yards.

Video below the fold. The news woman is annoying, but the footage is quite cool.
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The accumulated evidence from the Chelyabinsk meteorite now suggests the risk of large asteroid impacts might be ten times greater than previously estimated.

The accumulated evidence from the Chelyabinsk meteorite now suggests the risk of large asteroid impacts might be ten times greater than previously estimated.

The Chelyabinsk asteroid had approached Earth from a region of the sky that is inaccessible to ground-based telescopes. In the 6 weeks before the impact, it would have been visible above the horizon only during the daytime, when the sky is too bright to see objects of its size, says Borovička.

“The residual impact risk — from asteroids with yet-unknown orbits — is shifting to small-sized objects,” says Peter Brown, a planetary scientist at the University of Western Ontario in London, Canada, and an author on the Nature papers.

Of the millions of estimated near-Earth asteroids 10–20 metres in diameter, only about 500 have been catalogued. Models suggest that an object the size of the Chelyabinsk asteroid hits Earth once every 150 years on average, Brown says. But the number of observed impacts exceeding 1 kiloton of TNT over the past 20 years alone hints at an actual impact risk that may be an order of magnitude larger than previously assumed,

The data also now suggests that the Chelyabinsk asteroid was twice as big as previously thought, and that it had an almost identical orbit to a much larger already known asteroid.

Largest in a century.

More on today’s Russian meteorite: Largest in a century.

My earlier skepticism appears incorrect. This impact actually happened.

Note the article’s sense of outrage and panic that we aren’t looking for these types of rocks:

Although a network of telescopes watches for asteroids that might strike Earth, it is geared towards spotting larger objects — between 100 metres and a kilometre in size. “Objects like that are nearly impossible to see until a day or two before impact,” says Timothy Spahr, Director of the Minor Planet Center in Cambridge, Massachusetts, which tracks asteroids and small bodies. So far as he knows, he says, his centre also failed to spot the approaching rock.

Yet, today’s impact actually illustrates the wisdom of excluding this kind of small asteroid from searches. They aren’t big enough to do serious harm, and trying to find them would hamper searches for larger asteroids that do pose a serious risk.

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